Field-Erected, Flat-Bottom, LOX and LIN Storage Tanks

Table of Contents

Section                                                        Title                                                                Page

 

Purpose 3
Scope 3
Related Documents 3
Definitions 4
Design Basis 5
Inner and Outer Tank Pressure Control and Relief Devices 14
Foundation 15
Materials and Material Certification 16
Inspection and Testing 16
Cleaning and Drying 17
Painting 18
Fabrication 18
Packing and Shipping 19
Proposal 19
Supplier’s Drawings and Data 19
Records 20
     
Piping Information 21
Supplier Information Required With Proposal 24
     
Tank Schematic, Showing Nozzles 25
Arrangement of Base Insulation 26
  Multiple Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal and Pump Recycle Lines Nozzles (G1, V1, and W1), (G2, V2, and W2), and (G3, V3, and W3) 27
Shroud Plate for Multiple-Line Thermal Barrier in Outer Tank Bottom 28
Single Line Thermal Barrier in Outer Tank Sidewall (Nozzles X1, X2, X3, Y1, Y2, Y3, F, J, K and U) 29
Piping Transition Details (Nozzles E and S) 30
Relief Devices Arrangement – Roof  Manway M/N 31
Notes to Figure 7 32
Ice Catcher Detail for Vent Line 35
Mesh Basket – Protection Against Debris Accumulation 36
Details of Syphon Breaker 37
Nitrogen Purge Arrangement and Wrapper Detail – (Nozzle R) 38
Acceptable Arrangement for Elimination of Outer Tank Bottom 39
     
Minimum Level of Inspection 40
Nondestructive Testing 41
Foundation Loading Data Requirements 43
External Pressure Loading on Storage Tanks, Stiffener Ring Spacing and Sizing 44

 

Section                                                        Title                                                                Page

     
Material Manufacturer Listing 46
Air Products Standard Tank Dimensions, Nozzle Orientations, and Elevations 47
Air Products Standard Tank Arrangement 49
Alternative Line Thermal Barrier  Configurations – Outer Tank Bottom Exit 50
Single Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal 50
Two Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal 51
Three Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal and Pump Recycle Lines Nozzles 52
Four Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal and Pump Recycle Lines Nozzles 53
Four Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal and Pump Recycle Lines Nozzles (G1A, G1B, V1, and W1), (G2A, G2B, V2, and W2), and (G3A, G3B, V3, and W3) 54
Alternative Non-Standard Tank Configuration Thermal Barriers – Outer Tank Sidewall Exit 55
Single Line Thermal Barrier in Outer Tank Sidewall (Nozzles G1, G2, G3, V1, V2, V3, W1, W2, and W3) 55
Multiple Line Thermal Barrier in Outer Tank Sidewall (Nozzles F, G1, G2, G3, J, K, U, V1, V2, V3, W1, W2, W3, X1, X2, X3, Y1, Y2, and Y3) 56
Pressure Testing 57
Schematic of Hydro-Pneumatic Test Alternate # 1 58
Schematic of Hydro-Pneumatic Test Alternate # 2 59
Shop Fabrication 60
Field Fabrication 61
Total Out-of-Plumb 63
Out-of-Plumb of One Shell Course Relative to Another 63
“Peaking” Weld Distortion of a Vertical Seam 64
“Banding” Weld Distortion of a Horizontal Seam 64
Additional Requirements for Liquid Lines Exiting Inner Tank via Bottom 65
Liquid Outlet through Base Insulation 65
Tanks Requiring Internal Emergency Shut-off Valves 66
Tank Certificates 67
Inner Tank Shell Manway MS  (Welded) 68
Acceptable Inner Tank Shell Manway Detail 68
Reduced Stress Design 70
Seismic Design Requirements 72
Annular Spec Piping Analysis and Piping Local Load Assessment 73

 

Note:  Superscripts adjacent to manufacturer’s names or trade names refer to item numbers in Appendix E.

 

 

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1.         PURPOSE

 

1.1       This global engineering specification defines the general requirements for double-wall, flat-bottom, powder-insulated, purged, cryogenic storage tanks.

 

 

2.         SCOPE

 

2.1       This specification applies to the design, field fabrication, testing, inspection, cleaning, insulating, and painting of low-pressure, field-erected, liquid oxygen (LOX) and liquid nitrogen (LIN) storage tanks.

 

2.2       This specification will be accompanied with a project equipment specification (PES) that defines all project specific requirements.

 

2.3       Air Products standard tank sizes are stated in Appendix F. Nozzle locations and orientations are fixed for each nominal capacity tank. Some variations in geometry and capacity are permitted to ensure economic configuration. Unless specifically directed otherwise in the PES, the supplier shall offer an Air Products standard tank.

 

 

3.         RELATED DOCUMENTS

 

3.1       Air Products Engineering Documents

 

4WCM-61001            Electronic Documentation Submittals

4WEQ-1110               Material Qualification

4WEQ-1120               ASU Plant Positive Material Identification (PMI) Requirements

4WEQ-1526               Internal Shutoff Valves for Field-Erected, Flat-Bottom, LOX and LIN Storage Tanks

4WEQ-6804               Painting and Corrosion Protection of New Construction for Design Temperatures to 649C (1200F)

4WGN-10001            Shipment and Packing Specification for Material being Exported

4WGN-20001            Supplier Quality Requirements

4WGN-20002            Material Requirements

4WPI-INS001            Cellular Glass Thermal Insulation System for Cold and Cryogenic Piping and Equipment Material Symbol C

4WPI-INS002            Installation of Multi-Layer Thermal Insulation of Cryogenic Piping with Cellular Glass Symbol C1

4WPI-SW70001         Standard Clean (Class SC) Inspection and Acceptance Requirements

4WPI-SW70002         Process Clean (Class B) Inspection and Acceptance Requirements

4WPI-SW70003         Oxygen Clean (Class AA) Inspection and Acceptance Requirements

4WPI-EW80010         Safety Relief Valves

4WPI-EW80015         Rupture (Bursting) Discs and Holders

VDR                           Vendor Document Requirement

DOC0000095511       Chinese Manufactured Cellular-Glass Insulation for Field-Erected, Flat-Bottom, Cryogenic, LOX and LIN Storage Tanks

DOC0000375163       Chinese Manufactured Oxygen Compatible Cloth for Cryogenic Flat- Bottom Field-Erected, LOX and LIN Storage Tanks

ET000 MECH 0004     10″ Rupture Disk Specification (2 psig Tank)

ET000 MECH 0005     10″ Rupture Disk Specification (5 psig Tank)

ET000 MECH 0006     8″ Rupture Disk Specification (2 psig Tank)

ET000 MECH 0007     6″ Rupture Disk Specification (5 psig Tank)

ET000 MECH 0008     8″ Rupture Disk Specification (5 psig Tank)

ET000 MECH 0012     4×6  Series 9300 Pressure/Vacuum Relief Valve set at 0.138 bar g (2 psig)

ET000 MECH 0013     4×6  Series 9300 Pressure/Vacuum Relief Valve set at 0.345 bar g (5 psig)

ET000 MECH 0014     6×8  Series 9300 Pressure/Vacuum Relief Valve set at 0.138 bar g (2 psig)

ET000 MECH 0015     6×8  Series 9300 Pressure/Vacuum Relief Valve set at 0.345 bar g (5 psig)

ET000 MECH 0016     8×10 Series 9300 Pressure/Vacuum Relief Valve set at 0.138 bar g (2 psig)

ET000 MECH 0017     8×10 Series 9300 Pressure/Vacuum Relief Valve set at 0.345 bar g (5 psig)

ET000 MECH 0018     10×12 Series 9300 Pressure/Vacuum Relief Valve set at 0.138 bar g (2 psig)

ET000 MECH 0019     10×12 Series 9300 Pressure/Vacuum Relief Valve set at 0.345 bar g (5 psig)

 

3.2       American Petroleum Institute (API)

 

620                        Design and Construction of Large, Welded, Low-Pressure Storage Tanks, including Appendix Q.

 

3.3       American Society of Civil Engineers (ASCE)

 

7                            Minimum Design Loads for Buildings and Other Structures

 

3.4       The American Society of Mechanical Engineers (ASME)

 

BPVC, Section II                       Material Specifications

BPVC, Section V                        Nondestructive Examination

BPVC, Section VIII, Division 1   Pressure Vessels

B16.5                                       Pipe Flanges and Flanged Fittings NPS 1/2 through NPS 24

B16.11                                     Forged Fittings, Socket-Welding and Threaded

B31.3                                       Process Piping

 

3.5       British Standards

 

BS 7777        Flat-Bottomed, vertical cylindrical storage tanks for low temperature service

 

3.6       Latest edition and addenda of the above listed documents at the time the purchase order is awarded shall apply as specifically designated.

 

 

  1. DEFINITIONS

 

4.1       Supplier is the organization completing the design and shop fabrication.

 

4.2       Erector is the organization completing the construction on site. [Erector is also referred to as the Manufacturer in the API 620 standard.]

 

4.3       Inspector is the organization responsible for issuing a final certificate of construction (see paragraph 8.6.1).

 

4.4       Purchaser is the owner or the owner’s designated agent, such as an engineering contractor. This shall be Air Products unless stated otherwise.

 

4.5       NPS is Nominal Pipe Size (inches).

 

4.6       PES is the Project Equipment Specification or project-specific equipment data sheet.

 

Note:  When reference is made in this document to the PES, it shall be taken to include all attachments.

 

4.7       Air Products approval shall mean in writing before design or fabrication unless otherwise specified.

 

4.8       Approval Authority is an independent organization required to approve the design if required either by the customer or by the regulations in the country of tank operation.

4.9       Design Pressure is the maximum vapor pressure that has been considered at the top of the inner or outer tanks. It is the pressure that will appear on the nameplate and which the relief systems must ensure is not exceeded.

 

4.10    Calculating Pressure is the pressure used to determine the tank thickness at any particular location.

 

4.11    The units quoted in this document are in the SI system unless otherwise specified; Imperial equivalents are also quoted in parentheses when practicable. Pipe sizes are shown in NPS (inches).

 

 

5.         DESIGN BASIS

 

5.1       General Design Criteria

 

5.1.1   Unless stated otherwise the tank system shall be a single containment type having inner and outer tanks. The inner tank contains the cryogenic product and shall be liquid and vapor tight. The outer tank contains insulation and purge gas and shall be vapor tight.

 

5.1.2   The inner and outer tanks shall be of all-welded construction, designed and constructed according to the design code nominated in the PES, plus any statutory requirements of the country in which the tank is to be installed. If a design code is not nominated in the PES, API 620, Appendix Q shall be assumed.

 

5.1.3   The supplier and erector shall fully comply with the requirements of the PES and this engineering specification and its related documents. When the supplier or erector finds it necessary to deviate from any of these requirements, the deviation shall be specifically defined in the proposal and must be approved by Air Products before inclusion in the design or fabrication of the tank.

 

5.1.4   The design of the tank shall be submitted to Air Products for review and, when specified in the PES, by the Approval Authority before manufacture proceeds.

 

5.1.5   The process design conditions are stated in the PES.

 

5.1.6   Unless otherwise specified, the tank shall be erected on an elevated foundation provided by others.

 

5.1.7   Inner tank anchor straps, outer tank anchor straps or bolts/sleeves, and the thermal barriers’ foundation plates (see Figure 3) shall be provided by the supplier for installation by others.

 

5.1.8   The tank shall be equipped with piping and connections listed in Table 1 and illustrated in general terms in Figure 1. The required nozzle locations and orientations for Air Products standard tanks are stated in Appendix F. For other tanks, the required nozzle locations and orientations will be specified in the PES.

 

5.1.9   The design wind factors for tanks designed to ASCE 7-10 shall be as defined in the notes to Appendix F. When other local codes govern, design wind factors will be defined by Air Products in the PES.

 

5.1.10    Unless local regulations are more onerous, seismic design loads shall be determined according to API 620, Appendix L. API 620, Appendix L employs the methodology of API 650 Appendix E with modifications applying for API 620 Appendix Q tanks. An explanation and clarification of the requirements are given in appendix Q of this specification. The following design factors shall be used unless stated otherwise in the PES.

Importance Factor Ie = 1.0

Site Class = D stiff soil

 

Ss short period (0.2 second) spectral response acceleration

S1 1.0 second spectral response acceleration values are to be used

 

The applicable short period (0.2 second) spectral response acceleration Ss and the 1.0 second spectral response acceleration S1 values will be specified in the PES

 

The sloshing height shall be established using the API 620, Appendix L.

 

5.1.11    Self-supporting Roof designs shall be in accordance with API 620 or approved alternative design code. Alternative tank roof designs using a reinforced membrane design not covered by API 620 are acceptable, subject to Air Products approval of the analysis method at the bid stage. An inner tank reinforced membrane roof design shall not strengthen the shell to roof joint (compression ring), as it is intended for the compression ring to fail in preference to the anchors failing.

 

5.1.12    Supplier quality requirements are given in 4WGN-20001.

 

5.2          Inner Tank and Anchors

 

5.2.1      The inner tank shall be designed and constructed according to the design code, except as modified herein.

 

5.2.2      Design temperature shall be -196° to +65°C (-320 to +150F).

 

5.2.3      Unless otherwise specified, the vapor space design pressure for tanks shall be 0.138 bar g (2 psig) or 0.345 bar g (5 psig), the value being specified in the PES.

 

5.2.4      The shell internal calculating pressure shall be the vapor space design pressure + liquid head at that elevation when the tank is filled to capacity.

 

Density to be used to calculate liquid head shall be:

     
  LOX 1,142 kg/m3 (71.27 lb/ft3)
  LIN    808 kg/m3 (50.46 lb/ft3)

 

It is acceptable to vary the calculating pressure with elevation; in this case, the minimum required thickness of each tank course will be determined by its maximum calculating pressure.

 

5.2.5      The shell external pressure for calculating purposes shall be the summation of the:

 

  • Interspace purge pressure of 5 mbar (2 in H2O)
  • Inner-tank vacuum design pressure of 5 mbar (2 in H2O), Note the vacuum valve set point is nominally 2.5 mbar (1.0 in H2O). The actual value is a function of the valve size and material, but shall be less than 5 mbar (2 in H2O).
  • Perlite compaction pressure

 

5.2.5.1   The supplier shall use the perlite compaction pressure developed over five complete thermal cycles of the inner tank between ‑196 to +15C (-320 to 59F). The supplier shall be prepared to substantiate the adopted value of perlite compaction pressure when required by Air Products or an Approval Authority, but in no case shall a value less than +70 mbar (1.0 psi) be used.

 

5.2.5.2   Unless otherwise specified in the applicable design code, the number and size of stiffening rings required on the tanks shall be calculated using the methods given in Appendix D. A minimum safety factor of 2.0 against critical buckling shall be applied in the design of stiffener spacing and stiffener sizing.

 

5.2.6      The roof external pressure for calculating purposes shall be the summation of:

 

  • Interspace purge pressure of 5 mbar (2 in H2O)
  • Self weight
  • Inner-tank vacuum design pressure of 5 mbar (2 in H2O), Note the vacuum valve set point is nominally 2.5 mbar (1.0 in H2O). The actual value is a function of the valve size and material, but shall be less than 5 mbar (2 in H2O).
  • Hydrostatic head of perlite

 

The density of perlite for calculation shall be specified by the supplier, but in no case shall be less than 56 kg/m3 (3.5 lb/ft3).

 

5.2.7      Capacity and Freeboard

 

  • Capacity

–     The gross capacity shall be the net liquid capacity plus a vapor space of 5%; a minimum of 20% (1% of gross capacity) of which shall be provided in the cylindrical shell.

 

  • Freeboard requirement

–     The minimum freeboard provided in the cylindrical section of the tank shall be the greater of:

 

o    For seismic loads, sufficient freeboard to ensure that liquid does not impact the tank roof during earthquake sloshing,

o    For seismic loads a minimum freeboard of 300mm (1ft)

o    When stated in the PES a minimum volume of liquid

 

–     The freeboard and vapor space in the cylindrical shell requirements are not additive.

 

5.2.8      The design shall be such that during operation the tank always contains sufficient liquid to prevent uplift of the floor when subjected to the set pressure of the inner tank vacuum breaker and the outer tank breather.

 

Note:  This might require the provision of a weir around outlets in the base of the inner tank.

 

5.2.9      When determining the tank size, the volumetric capacity (net liquid capacity) in the cold condition shall be taken as the volume between the maximum liquid level and either the bottom of the product outlet nozzle or the top of a weir if fitted, whichever results in the lower capacity.

 

5.2.10    Materials of construction shall be according to the design code, except that aluminum construction is not permitted.

 

5.2.11    The materials used for attachments, such as clips, rings and supports, shall be the same as those of the tank and shall be suitable for service at a temperature of -196°C (-320°F).

 

5.2.12    The joint between the side wall of the inner tank and the bottom plate shall be a continuous double sided and full-penetration weld, with a fillet capping weld on both sides of the vertical wall.

 

5.2.13    Inner tank shell stiffening rings shall be located on the shell’s outside surface.

 

5.2.14    A “mousehole” shall be provided in the stiffeners at the location of vertical shell seams to avoid welding on the seams of the tank and at each radial joint between stiffening rings sections. The stiffener attachment weld passes shall be continuous through the mouseholes. Radial welds shall be full penetration.

 

5.2.15    For LOX tanks, cleanliness concerns dictate that special attention be paid to reinforcing pads, doubler plates, lap welds, and other attachments to the tank interior. Lap-welded roofs, internal roof support-beam joists, and other reinforcing plates and stiffeners in the vapor space shall be seal welded for cleanliness. Internal shell attachments directly exposed to LOX shall be welded with full-penetration welds to eliminate any crevices, and there shall be no pad-type attachments inside the inner tank below the liquid level.

 

5.2.16    Pad-type attachments below the liquid level in liquid nitrogen service shall be stitch welded to avoid problems with the expansion of trapped liquid.

 

5.2.17    Straps shall be used for the inner tank anchorage. A minimum of sixteen (16) anchor straps shall be provided for the inner tank. The maximum strap spacing shall not exceed 2000 mm (6.5 ft).

 

5.2.18    The entire anchor-strap assemblies, including the base plates embedded in the concrete, shall be fabricated with materials suitable for service at -196°C (-320°F). The material shall be identifiable against mill certificates that indicate chemical composition and mechanical properties.

 

5.2.19    All load-carrying weld joints in the inner tank anchor system shall be 100% nondestructively tested according to Appendix B. Load-carrying fillet welds shall be made with a minimum of two passes.

 

5.2.20    The anchor strap attachment to the shell shall be above the tank distortion region, defined as  from the tank base, where R is the radius of the inner tank shell and T is the thickness of the inner tank bottom shell course. R and T shall both be in millimeters or shall both be in inches. As a minimum, the attachment to the shell shall be 750 mm (30 in) from the tank base.

 

The tank anchor strap joint shall have a reinforcing plate on the inner tank shell. The tank anchor straps shall be welded to the reinforcing after the inner tank has been filled with water to maximum liquid level for the pressure test (overfill nozzle E), but prior to application of the pneumatic test pressure.

 

5.2.21    The compression ring shall be as shown in detail f or g of Figure 5-6 in API 620. The minimum anchorage shall also be designed for three times the internal design pressure. The allowable stress for this loading case shall be 90% of the minimum specified yield strength of the anchorage material.

 

5.2.22    Radial welds in the compression ring shall be full penetration.

 

 

5.2.23    The weld joint between the compression ring and the top shell course shall be continuous double sided and full penetration.

 

5.2.24    All gaskets used on flanges of manways or piping to the inner tank shall be Flexitallic,1 Permanite Sigma 511.

 

5.2.25    When using the shielded metal arc welding (SMAW) process for 304, 304L, 316, and 316L stainless steel, the weld electrodes shall be E316L-15 meeting the requirements of
ASME BPVC, Section II, Part C, SFA-5.4.

 

5.2.26    All shell welds shall be double sided full penetration butt welds.

5.3       Process Piping

 

5.3.1   The storage tank shall be equipped with piping to the inner tank as indicated in Table 1 and Figure 1. Line sizes that are not defined in this specification will be defined in the PES. Nozzle identification letters in Table 1 refer to Figure 1.

 

5.3.2   All piping material and fabrication techniques used to connect the inner and outer tanks shall be according to ASME B31.3. Aluminum piping is not permitted.

 

5.3.3   No flanged joints, bellows, transition joints, or flexible metal hoses shall be used in the annular space between the inner and outer tanks. This restriction does not apply to the connection R, the nitrogen purge (see Figure 11).

 

5.3.4   All joints in the piping in the annular space between the inner and outer tanks shall be full penetration butt-welds. This restriction does not apply to the connection R, the nitrogen purge (see Figure 11).

 

5.3.5   Non-removable backing strips or rings are not permitted. Single-sided piping welds in stainless steel shall use a gas tungsten arc weld (GTAW) root run to ensure full penetration and sound root.

 

5.3.6   Liquid lines connecting to the inner tank below maximum liquid level shall not be less than schedule 40s. All other pipes shall not be less than schedule 10s. All piping, liquid or vapor lines shall be 40s minimum schedule locally at the penetration to the inner tank and the outer tank penetration plate or thermal barrier plate (see figures 3, 5 and 6).

 

5.3.7   Liquid withdrawal (liquid outlet) lines designated G1, G2, and G3 as defined in Table 1 shall be according to the following:

 

Be designed for the maximum combined stress as a result from the following:

 

–     Pressure

–     Dead load

–     Settlement (10 mm/m for the cellular glass base insulation)

–     Thermal loading, transient or steady-state (including appropriate stress-intensification factors)

 

  • The maximum combined stress does not exceed the maximum allowable stress value “S” indicated in ASME BPVC Section VIII, Division 1 and Section II for the material used. The use of an increased basic allowable membrane stress stated in API 620 Q.3.4 shall not be applied. The use of increased allowables such as 2S or 2.5S for stress combinations is not permitted.

 

Have all circumferential welds 100% radiographed. Radiographic examinations shall be performed according to ASME B31.3

 

5.3.8   All piping between the inner and outer tanks shall be provided with sufficient flexibility to permit movement resulting from thermal contraction of the inner tank, outer tank and the pipe. The methodology and acceptance criteria are stated in detail in Appendix R.

 

5.3.9   Unless agreed otherwise, liquid withdrawal lines will exit the inner tank via the side wall and the outer tank through the elevated foundation as shown in Figure 3. The lines shall slope continuously downward toward the outer tank. Whenever possible, the slope shall be 1 in 25 but shall never be less than 1 in 40. Lines may locally be run level at the outer tank penetrations, inner tank penetrations and inside the inner tank. No trapping or upward sloping is permitted. A maximum of three elbows is permitted.

 

5.3.10 All lines shall be adequately supported so that vertical deflections resulting from dead weight do not exceed 13 mm (1/2 in).

 

 

5.3.11    Piping shall not be designed to be pre-stressed.

 

5.3.11.1 [Pre-stressing is the practice of welding a pipe in a deflected position at ambient temperature with the intention of reducing the stress resulting from thermal contraction upon cooldown, this practice is unreliable].

 

5.3.12    Multiple-Line Thermal Barriers:  Each liquid withdrawal line (G) and associated pair of pump recycle lines (V and W) shall terminate in a common Type 304 stainless steel thermal barrier. The thermal barrier shall penetrate the outer tank base and the elevated concrete foundation below the tank annular space. The standard arrangement is shown in Figure 3. Each Multiple-Line Thermal Barrier shall have a shroud plate as detailed in Figure 4.

 

5.3.13    The lines in each thermal barrier share the same number suffix (for example, the first thermal barrier contains G1, V1, and W1).

 

5.3.14    Multiple-Line Thermal Barriers can have horizontal or vertical pumps associated with them. The pumps are not included in the supplier’s scope. When vertical pumps are fitted, two additional pump casing vent lines, X and Y, are required. These lines enter the tank annular space through single-line thermal barriers located in the outer tank sidewall as shown in Figure 5. These additional pump casing vent lines share the same number suffix as the associated liquid outlet (for example, for G1 the additional pump casing vent lines will be X1 and Y1).

 

               Note:  When horizontal pumps are fitted, lines X and Y are not required.

 

5.3.15    The required number of liquid withdrawal lines will be stated in the PES. Normally, tanks will have 1, 2, or 3 liquid withdrawal lines, designated G1, G2, and G3. The PES will also state which recycle lines and pump casing vent lines are to be fitted.

 

5.3.16    Each multiple line thermal barrier shall include a dry air purge system for the gap between the barrier and the concrete foundation. Each purge system shall consist of a drilled pipe ring at the top of the gap and a feed line. Each system shall be fitted as part of the stainless steel thermal barrier. The piping shall be NPS 1/2 with 3 mm (1/8 in) diameter holes on a pitch of 100 mm (4 in) for the ring (see Figure 3).

 

5.3.17    Liquid withdrawal piping shall not be welded outside the thermal distance piece (see
Figures 3 and 5).

 

5.3.18    A typical arrangement for the annular space nitrogen purge pipe (R) is shown in Figure 11. The supplier may offer an alternative arrangement. For outer tanks complete with a floor, the purge piping shall be located near the base of the outer tank. When the outer tank floor is omitted (see paragraph 5.4.18), the purge pipe shall be located at the top of the outer tank cylindrical section within 500 mm (20 in) of the curb to facilitate a downward purge.

 

5.3.19    The pipe supports shall be stainless steel, except for the annular space purge line R supports, which may be carbon steel if they are attached to the outer tank wall.

 

5.3.20    Piping connections to the inner tank shall made by full penetration welds, only connection types g, h, m, o, as shown in API 620 figure 5-8 panels are acceptable.

 

5.3.21    Piping local load assessment is required to be carried out for each line, the piping loads on the inner and outer tanks shall be analyzed as detailed in appendix R.

 

5.3.22    The line pressure considered in the piping analysis shall include the liquid static head plus the gas design pressure, alternatively a maximum piping design pressure of 3.45 bar g may be adopted.

 

5.4             Outer Tank

 

5.4.1         The outer tank shall be designed and constructed according to the design code except as modified herein.

5.4.2      Design temperature shall be as required by the design and construction code unless otherwise specified in the PES.

 

5.4.3      Internal design pressure shall be 5 mbar (2 in H2O) the interspace purge pressure. The internal calculating pressure shall be the internal design pressure, plus perlite compaction pressure as defined for the inner tank.

 

5.4.4      The external design pressure shall be 5.0 mbar (2.0 in H2O).  Note this is greater than the vacuum valve set point which is 2.5 mbar (1.0 in H2O). The external calculating pressure shall be the external design pressure plus external loads such as roof platforms, wind, and snow.

 

5.4.5      There shall be no corrosion allowance.

 

5.4.6      Unless agreed otherwise, the outer tank size shall be an Air Products standard tank according to Appendix F. The outer tank size for non-Air Products standard tanks shall be determined by the supplier unless otherwise specified. Size shall be such as to provide an insulation space that will limit the heat gain as specified in the PES. If this information is not specified in the PES, the conditions outlined in paragraph 5.5 shall be used.

 

5.4.7      A minimum of eight anchor straps or bolts shall be provided for the outer tank. The maximum strap or bolt spacing shall not exceed 5000 mm (16 ft).

 

5.4.8      When outer tank anchor bolts are fitted, they shall have a positive locking mechanism for the nut on the bolt, such as a locking nut.

 

5.4.9      Snow deflectors (tank roof edge toe plates) with a minimum height of 150 mm (6 in) shall be provided around the tank roof perimeter if specified in the PES. A drainage gap shall be provided at the base of the snow deflectors.

 

5.4.10    The tank shall be equipped with a work area at the center of the roof, a ladder or spiral stairway, and a walkway that joins the work area to the ladder or stairway. The supplier shall offer the less expensive option of ladders or stairway. Either option shall include a maintenance davit to permit the raising and lowering of tools and relief valves weighing up to 225 kg (500 lb).

 

5.4.11    The work area shall be complete with handrails and toe plates. The work area in the center of the tank does not require a platform when the slope does not exceed 1:5 ratio and provision is made to seal the gap between the inner perimeter of any annular platform and the tank roof to prevent passage of small items and tools.

 

5.4.12    If a platform is omitted, a nonslip paint surface shall be provided. Silver sand shall be placed on the first of the “final” paint coats while still damp, with excess sand removed when dry. The surface shall then be finish painted.

 

5.4.13    Safety valves, vent line valves, and access for valve operation and maintenance shall be within the platform area (see Figure 7).

 

5.4.14    All platforms, walkways, stairways, ladders, handrails, and toe plates may be according to the supplier’s standards. All handrails shall be made from angles, flats, or solid sections (tubular products shall not be used). The design and installation shall be according to all local and national regulations.

 

5.4.15    All connections to the tank shell or roof, such as stairway treads, shall be completely seal-welded.

 

5.4.16    The required orientations of stairs and ladders will be specified by Air Products.

 

5.4.17    When floor grating is used, the back face of flanges or nozzles penetrating the platform shall be a minimum of 100 mm (4 in) above the toe board of the platform. Manways may be flanged below the platform level if removable gratings are supplied.

5.4.18    Unless agreed otherwise, the perimeter of the outer tank base shall be flat. Water flow under the tank base plate shall be prevented by the use of a ring of mastic sealant under the plate perimeter. This sealant shall be provided and applied by the erector.

 

5.4.19    The supplier may offer an outer tank without a floor if a suitable sealing arrangement can be demonstrated. An acceptable arrangement is shown in Figure 12.

 

5.4.20    For tanks provided to Air Products in Europe, the outer tank shall have four grounding/earthing bosses, 24 mm diameter by 40 mm long, tapped M10 for a minimum depth of 25 mm. Tanks supplied to Air Products in America need not be provided with bosses.

              

5.4.21    If wind girders are required for the outer tank shell, they shall be located on the inside surface.

 

5.5          Heat Gain and Insulation

 

5.5.1      Unless otherwise specified, the total heat gain through the insulation space, piping, supports, and other connections shall be such that the loss of product per day does not exceed 0.22% for a LOX tank or 0.30% for a LIN tank when the tank has been filled to rated capacity with the liquid for which it is designed and allowed to reach equilibrium. Heat gain shall be based on ambient conditions of
26.7C (80°F) and 1.0135 bar a (14.7 psia).

Note:  These are average ambient conditions for 24 hours.

 

5.5.2      Since loss of product is an important consideration for tanks, the supplier shall quote supplier’s best guaranteed heat gain if it is less than the heat gain specified. The supplier’s guaranteed heat gain will be considered in evaluating bids. Supplier’s calculated heat gain shall be submitted with the quotation (along with the guaranteed heat gain).

 

5.5.3      Annular space insulation shall be expanded perlite ore, except for nozzle transitions, at which mineral wool (ceramic fiber), 96 kg/m3 (6 lb/ft3) density shall be used.

 

Acceptable mineral wool products are listed below:

 

  Product/Grade Supplier  
  Rockwool Rockwool10  
  Kaowool Kaowool4  

 

The manufacturer and grade of perlite to be used shall be specified by the supplier. The manufacturer, grade, and density of perlite are subject to approval by Air Products.

 

5.5.4      Bottom insulation between the inner and outer tanks bases shall be cellular glass blocks and shall be installed by the erector. Unless otherwise agreed, the thickness of the cellular glass shall be 750 mm (2 ft 6 in) minimum. This insulation shall extend not less than 300 mm (12 in) beyond the outside of the inner tank (see Figure 2).

 

Approved grades and suppliers are listed below:

 

  Product/Grade Supplier Value to be used for “Published strength” 
  HLB 800 Foamglas Pittsburgh Corning3 8.0 bar (116 psi)
  ZES -1000 Zhenshen & Zhenhua22

 

8.0 bar (116 psi)
  HLB 1000 Foamglas Pittsburgh Corning3 10.0 bar (145 psi)
  HLB 1200 Foamglas Pittsburgh Corning3 12.0 bar (174 psi)

Notes:

 

ZES -1000 has a published strength of 10 bar; however, based on the results of Air Products approval testing, it has been down rated to 8 bar for this high load bearing application.

 

HLB 800, HLB 1000, and HLB 1200 Foamglas undergo in-production batch testing, including compressive strength crush testing. This testing is included in and required by the manufacturer’s quality plans. ZES -1000 does not undergo in-production batch testing. Therefore, to verify the crush strength of the batch(s) of ZES -1000 cellular glass supplied, Air Products requires that they are tested to the requirements stated in DOC000095511.

 

5.5.5   The cellular glass base insulation system shall have a minimum safety factor of 2.5 against compressive collapse under normal design conditions and a safety factor of 2.0 against compressive collapse under seismic loading.

 

5.5.6   The compressive strength and amount of crushing of the cellular glass system depends on the capping and interleaving material used between the layers of cellular glass. The published compressive strength values are determined by using an ASTM test that uses bitumen as the capping material. The use of bitumen is not acceptable in oxygen tanks. Tests have shown that approximately 75% of the published compressive strength value can be achieved by using a combination of dry, inorganic powder to fill the open-cell structure on the top and bottom of each cellular glass block and by using an oxygen-compatible glass cloth to separate layers of cellular glass blocks, see Figure 2.

 

Acceptable inorganic powders are:

 

  Product/Grade Supplier
  PC85 Pittsburgh Corning3
  Hydrocal B11 Pittsburgh Corning3

 

Acceptable oxygen-compatible glass cloth products are:

 

  Product/Grade Supplier
  Interglas 92200 Interglas15
  Marglas  – Style 327 finish loom state Marglas12
  JPS Glass Tex – Style 2025 finish 9383 JPS17
  JPS Glass Tex Style 2035,finish 9383 JPS17

 

  2025 to DOC0000375163 Shanghai Acmetx23

 

5.5.7      When the above system of powder and cloth is used, 75% of the published average compressive strength value of the cellular glass may be used to determine the allowable design loading. Therefore, the allowable Design Compressive Loading = [0.75 / (2 or 2.5 as appropriate)] x cellular glass block supplier’s published compressive strength value.

 

5.5.8      The supplier may propose an alternative interlayer system and design loads if test data is available to justify the design. The grade of cellular glass proposed must always be included in the bid submission.

 

5.5.9      Air Products’ preferred method of laying the cellular glass blocks, inorganic powder, and interleaving material is indicated in Figure 2; however, the supplier may propose any alternative scheme that offers an advantage, if the claim can be substantiated.

 

5.5.10    The cellular glass blocks in each layer shall be laid side-by-side in rows without overlapping, but successive layers shall be staggered in two directions (see Figure 2). The use of pieces with plan dimensions less than half a block shall be avoided; this is particularly important at the edge of the cellular glass layer, which is the region with the highest loads (see Figure 2).

 

5.5.11    Any channels made in the cellular glass base insulation for anchor straps shall be filled with mineral wool insulation (ceramic fiber). Such channels shall be sized and positioned to accommodate thermal movement of the inner tank that occurs upon cooldown.

 

5.5.12    The inner tank bottom and sidewall shall not rest directly on the cellular glass, but shall have a concrete footing/leveling layer on top of the cellular glass blocks to spread the load and protect the foamglass during floor construction. In some cases, a concrete ring beam may be required under the sidewall. Any reinforcing bars in the concrete ring beam shall be stainless steel. Carbon steel reinforcing bars may be used in the concrete leveling layers above and below the cellular glass base insulation.

 

5.5.13    The inner tank base insulation shall be installed under dry conditions. Generally, this will be within the completed outer tank. The supplier may offer the option of an alternative arrangement that will be subject to Air Products approval. During construction, the outer perimeter of the base insulation shall be protected from damage.

 

5.5.14    The vent line (B) shall be insulated with cellular insulation according to 4WPI-INS001 and
4WPI-INS002. The thickness of insulation shall be as follows:

 

  Line B Size DN (NPS) Insulation Thickness (mm)
                  80  (3) 127
                 100  (4) 152
                 150  (6) 178
                 200   (8) 178

 

5.5.15    All insulation materials used in LOX tanks shall be approved by Air Products for oxygen service.

 

 

  1. INNER AND OUTER TANK PRESSURE CONTROL AND RELIEF DEVICES

 

6.1          Inner Tank Relief Devices

 

6.1.1      Inner Tank Combined Pressure and Vacuum Relief Valve—Pilot-operated with remote pressure pickup extending into inner tank vapor space. The manufacture, model number, and size options, are stated in Note 1 of Figure 7. The required size and set pressures are stated in the PES. The general requirements for relief valves are given in engineering specification 4WPI-EW80010.

 

6.1.2      Inner Tank Rupture Disc—The manufacture and size options are stated in Note 9 of Figure 7. The actual requirements will be according to Air Products project-specific documentation. The rupture disc size shall never be less than that of the relief valves specified. The general requirements for rupture (bursting) discs and holders are given in engineering specification 4WPI-EW80015.

6.1.3   A PIC-controlled valve is required to control the pressure in the inner tank. The type options, size options, manufacture and model number combinations, are stated in Note 8 of Figure 7. The size and type of the PIC-controlled valve will be stated by Air Products in the PES.

 

6.2       Outer Tank Relief Devices

 

6.2.1   Outer Tank Combined Pressure/Vacuum Breather Valve—Set points are 5 mbar (2 in H2O) pressure and 2.5 mbar (1.0 in H2O) vacuum. The device size shall be a minimum of 4″. Tank supplier will size. See nozzle “Q” in Table 1.

 

The over pressure for the vacuum case shall be limited to 5 mbar (2in H2O).

 

A 15 (1/2″) branch from nozzle with bleed valve, Herose7 0135.0400.7906 globe valve, 15 (1/2″) FNPT (Air Products valve designator WXBNGL030TFHE01) is required.

 

Approved models and suppliers are listed below:

 

  Product Model Supplier  
  94020 Shand and Jurs6  
  1200A Groth18  
  4020A Whessoe11  
  CNC380 Motherwell14  
  121 AG Marvac19  
  54SWF Lupi24  

 

6.2.2   Outer Tank Emergency Vent—A 500 mm (20″) emergency vent. Set to relieve at 7.5 mbar (3 in H2O). This shall be mounted on 500 mm (20″) manway, see Nozzle “P1”, Table 1.

 

Approved models and suppliers are listed below:

 

  Product Model Supplier  
  94210 Shand and Jurs6  
  2000A Groth18  
  4210A Whessoe11  
  CNC121 Motherwell14  
  785 AG Marvac19  
  104STD Lupi24  

 

 

  1. FOUNDATION

 

7.1       Unless otherwise specified, the tank shall be erected on an elevated, piled-concrete slab foundation provided by Air Products that is between 500 mm (20 in) and 1000 mm (40 in) thick. The top of the slab will be approximately 4000 mm (13 ft) above the plant datum and will be level within 6 mm (1/4 in) at points 6000 mm (20 ft) apart, measured from a common datum. The top will be flat without any steps or slopes at the edge.

 

7.2       The erector shall check the foundation before accepting it from Air Products.

 

7.3       The tank supplier shall provide Air Products with an anchor-strap/bolt setting plan that shall include the required tolerances on location. The supplier shall provide inner tank straps, outer tank straps or bolts/sleeves, and multiple-line, thermal-sleeve, attachment plates (if applicable, see Figure 3), to be cast into the concrete by Air Products.

  1. MATERIALS AND MATERIAL CERTIFICATION

 

8.1       All pressure containing material forming the stainless steel inner tank, piping (including elbows and fittings) any material welded to the tank or piping shall be ASME material and/or material dual certified as ASME material. With prior agreement alternative material may be used for the outer tank.

 

8.2       All material used for pressure and/or structural load carrying shall comply with 4WGN-20002 and when applicable 4WEQ-1110.

 

8.3       Material certification shall be as follows:

 

  Material Country of Origin Required Certification  
  Metallic material originating in the USA Mill Certification  
  Metallic material originating in an AP “Qualified” country EN 10204 Type 3.1 Inspection Certification  
  Metallic material originating in an AP “Unqualified” country Material approved by re-testing in accordance with 4WEQ-1110.  

 

9.         INSPECTION AND TESTING

 

9.1       Nondestructive Testing

 

9.1.1   Nondestructive testing shall be executed according to the applicable design code. This shall not be less than specified in Appendix B.

 

9.1.2   Radiography and interpretation shall be according to the requirements of ASME BPVC, Section V and Section VIII, Division 1, as a minimum. The minimum length of spot radiographs shall be 380 mm (15 in).

 

9.1.3   Radiographs shall be presented to the Inspector for approval, throughout the tank construction.

 

9.1.4   Any welded areas at which the interpretation of a dye-penetrant indication is in doubt shall be ground, rewelded, and reinspected.

 

9.1.5   When any materials for the inner tank and interspace piping, originates from ‘unqualified countries’ as defined in 4WGN-20002, 100% PMI shall be carried out by the site fabrication contractor as detailed in 4WEQ-1120.

 

9.2       Pressure Testing

 

9.2.1   The pressure testing requirements are stated in Appendix I.

 

9.3       Heat Gain Test:  A test of the total heat gain into the tank might be conducted by Air Products or the Air Products customer after the tank has been placed in service, at a time and according to a procedure agreed to by the supplier and Air Products.

 

9.4       Air Products Inspection

 

9.4.1   In addition to the Inspector, Air Products shall be at liberty to perform its own inspection at any stage of manufacture and erection.

 

9.4.2   Air Products reserves the right to perform final inspection in the supplier’s shop/works of the following:

 

Block valves

Rupture/bursting disc tests

Relief devices

 

9.5       Supplier Inspection

 

9.5.1   The tank Supplier shall provide inspection (the Inspector) for the prefabrication (shop fabrication) scope of supply to ensure the requirements of the rules have been satisfied so that he can sign the Supplier’s partial tank certificate attesting that the tank has been constructed to the rules of the API 620 standard, this specification, and the PES. (See Appendix N for partial Tank Certificate format.)

 

9.5.2   This inspection may be executed by the supplier’s qualified QA representative.

 

9.6       Manufacturer (Erector) Inspection

 

9.6.1   The tank manufacturer shall provide inspection (the Inspector) to ensure the requirements of the rules have been satisfied so that he can sign the  manufacturer’s tank certificate attesting that the tank has been constructed to the rules of the API 620 standard, this specification, and the PES. See Appendix N for Manufacturer’s Tank Certificate format.

 

9.6.2   This inspection may be executed by the supplier’s or the manufacturer’s qualified QA representative.

 

9.6.3   In cases where the tank manufacturer (Erector) is also the tank supplier, the requirements of paragraphs 9.5 and 9.6 may be combined.

 

9.7       Independent Inspection (Purchasers Inspector)

 

9.7.1   As required by API 620 the tank Purchaser shall employ an independent inspector. This independent inspector shall perform all inspections required by API 620 and this specification. The independent inspector shall also sign the Supplier’s partial tank certificate and the Manufacturer’s tank certificate attesting that the tank has been constructed to the rules of the API 620 standard, this specification, and the PES. In cases where the manufacturer is different from the supplier, Purchasers Inspector function may be performed by a representative of the tank supplier under contract to the purchaser.

 

 

9.7.2   The inspection of the inner tank and piping will include, as a minimum, those items in Appendix A.

 

9.7.3   Unless otherwise specified in the PES, design approval will be by Air Products.

 

9.8       Inspection Qualification

 

Both the tank supplier’s and the tank manufacturer’s own internal inspectors and the independent inspector shall meet API 620 minimum training/experience requirements. For example:

 

  • A Minimum of 5 years’ experience in design, construction, maintenance/repair or construction supervision of pressure vessels or tanks of which:

 

–     At least one year in construction of pressure vessels or tanks by fusion welding.

–     Suitable training courses may be used to replace up to 3 of the 5 years’ experience, and up to 6 months of the 1 year fusion welding experience.

 

 

  1. CLEANING AND DRYING

 

10.1    General

 

10.1.1 The methods to be used to clean and inspect all surfaces shall be submitted by the supplier in the bid. These methods shall be subject to approval by Air Products.

 

10.2       Inner Tank Cleaning Requirements

 

10.2.1    For LIN tanks, the internal surfaces of the inner tank and the piping shall be cleaned to meet Class B acceptance criteria as defined by 4WPI-SW70002.

 

10.2.2    For LOX tanks, the internal surfaces of the inner tank and the piping shall be cleaned to meet Class AA acceptance criteria as defined by 4WPI-SW70003.

 

10.2.3    For both LOX and LIN tanks, all components of the inner-tank relief devices shall have their internal surfaces cleaned to meet Class AA acceptance criteria as defined by 4WPI‑SW70003.

 

10.2.4    Normally, Air Products inspection of the inner tank surface will be performed on a random basis. However, the supplier shall provide special staging or scaffolding for inspection of the entire surface of the inner tank if the Air Products representative deems it necessary.

 

10.2.5    Air Products does not require suppliers to pickle and passivate stainless steel cold-formed parts in the supplier’s fabrication shop; however, any hot-formed parts or cold-formed and subsequently heated-treated parts shall be pickled and passivated.

 

10.3       Annular-Space Cleaning

 

10.3.1    The external surface of the inner tank and piping and the inner surfaces of the outer tank shall be cleaned to meet Class SC acceptance criteria as defined by 4WPI‑SW70001.

 

10.3.2    In addition, all hydrocarbons visible to the naked eye in bright, white light shall be removed. The presence of contamination will be cause for additional local cleaning at no additional cost to Air Products.

 

10.4       Drying:  Following testing and cleaning, the inner tank and the annular space and its insulation shall be dried with oil-free, dry nitrogen gas until the effluent purge gas at every line reaches a dew point of -20°C (-4F) for inner tank and -10°C (14F) for the annular space as indicated by an Alnor5 dew pointer or equal apparatus. All inner tank covers shall be sealed with clean gaskets. The inner tank and the outer tank shall be sealed with positive gaseous nitrogen pressure within the safe limits of the tank design.

 

 

11.          PAINTING

 

11.1       Unless stated otherwise in the PES, the outside of the outer tank shall be prepared and painted according to Air Products specification 4WEQ-6804. The required paint code is C093-U3. The shop fabricated outer tank parts shall be prime painted prior for transportation to the erection site, the extent of the prime painting is stated in appendix J.

 

11.2       Painting of weld seams shall not be executed until testing of the outer tank is complete. Each coat of paint shall be tinted to differentiate it from the previous coat.

 

11.3       If steel surfaces are primer-coated in the shop, the primer application shall be stopped 50 mm (2 in) from all edges that are to be welded after priming.

11.4       Platforms, walkways, ladders, stairs, and lifting davit shall be hot dip galvanized.

 

12.          FABRICATION

 

12.1       Shop Fabrication – See Appendix J.

12.2       Field Fabrication – See Appendix K.

 

 

  1. PACKING AND SHIPPING

 

13.1    Packing and shipping requirement are given in 4WGN-10001

 

 

14.       PROPOSAL

 

14.1    The proposal shall contain, but not be limited to, the following:

 

  • Completed data sheet (see Table 2)
  • Exceptions to this specification
  • Complete description of offering
  • Any additional information requested in the PES

 

15.       sUPPLIER’S DRAWINGS AND data

 

15.1    The supplier shall provide the drawings, data, procedures, and calculations strictly according to Air Products VDR, which accompanies the inquiry for quotation and the purchase order. Drawings shall specify all materials, including weld metal, in terms of thickness, specification and grade, and shall include weld-procedure numbers and weld preparations. Drawings shall cite design conditions and the relevant design code.

 

15.2    The general arrangement drawing shall contain the following information as a minimum:

 

  • Inner-tank height to curb
  • Inner-tank inside diameter
  • Inner-tank roof inside radius
  • Inner-tank overall height/elevation
  • Inner-tank plate thicknesses, floor, shell, and roof
  • Maximum liquid level (Nozzle E)
  • Height of product that cannot be released from the tank (see paragraph 5.2.9)
  • Tank freeboard
  • Outer-tank height to curb
  • Outer-tank inside diameter
  • Outer-tank roof inside radius
  • Outer-tank overall height
  • Outer-tank plate thicknesses, floor, shell, and roof
  • Stairway or ladder location (including top and bottom orientations)
  • Platform elevation
  • Relief device arrangement and orientation (in roof work area)
  • A table that contains the following nozzle information:  service, type, size, rating (schedule), end preparation, location, and projection including vents, drains, and manways
  • A table that contains the following information:

–     Design code

–     Design pressure and temperature inner and outer tanks

–     Internal and external calculating pressures for inner and outer tanks

–     Operating pressure and temperature inner and outer tanks

–     Test pressure and temperature inner and outer tanks

–     Tank capacity (releasable)

–     Wind design code

–     Wind design conditions

–     Seismic design code

–     Seismic design conditions

–     Materials of construction

–     Relief device tags, manufacturers, type and model, sizes, set pressures and tolerances

–     Control valve, tags, manufacturers, type and model, sizes

–     Manual valve tags, manufacturers, type and model

 

15.3    Inner tank anchor-strap and outer tank anchor-strap/bolt setting plan that includes the required tolerances on location shall be provided to facilitate the foundation design.

 

15.4    All fabrication drawings shall indicate site welds with a flag symbol.

 

15.5    Deviations from the approved drawings and specifications shall not be permitted unless prior written authority has been obtained from Air Products and the Inspector.

 

15.6    Approval of documents such as drawings and specifications by Air Products shall not relieve the supplier of responsibility for accuracy of dimensions, code requirements, or warranty.

 

15.7    Unless agreed otherwise, all correspondence and documentation shall be in the English language and SI units, with pressures expressed in mbar g. Other languages may be used if a 1:1 English translation is provided.

 

15.8    Unless agreed otherwise, all documents shall have a 100 mm wide x 80 mm deep “clear” area above the title block for Air Products Supplier Data Tracking System (SDTS) bar code and review status stamp. For small documents (that is, A4 or “letter” size), a cover sheet shall be provided.

 

15.9    An internationally recognized weld symbolic representation shall be used on fabrication drawings.  ISO 2553 or AWS A2-4 are acceptable. Weld procedures shall either be stated at each weld symbol or a separate weld map may be used, provided sufficient detail is given and that the weld map is referenced by number on each fabrication drawing.

 

15.10  Documentation shall be submitted to Air Products by the methods and in the format stated in 4WCM-61001.

 

15.11  Design drawings shall configured such that sufficient information is provided in the minimum number of drawings. Sufficient dimensional information for parts on a drawing shall be included on that drawing to enable drawing review to be completed without need to review numerous parts drawings.

 

15.12  Calculations shall be adequately annotated with sketches and code section references and equation references. When a calculation uses multiple codes such as seismic design calculations (API 620, API 650 and ASME VIII Div 1), it shall reference the code section or equation.

 

 

16.       RECORDS

 

16.1    The supplier shall maintain records throughout manufacture and erection and shall make them available to the Air Products representative and to the Inspector on request.

 

16.2    The supplier shall provide “Vessel Dossiers.” The required contents and format of the information will be detailed in the “Vessel Dossier Requirements” form or the “Final Documentation Requirements” document. That form will be part of the requisition.

 

 

 

 

                                                                                                                     Table 1                                                                                                                                    

 

Piping Information

 

 

 

 

NOZZLE

IDENTIFICATION

LETTER

 

SERVICE

(LIQUID/VAPOR)

 

DN (NPS)

(Inches) & Schedule

END

PREP (Schedule)

 

 

LOCATION

 

 

REMARKS

             
 

 

 

A1 Primary Relief Vacuum Breaker

(Vapor)

*   At center on outer tank roof, branching from inner tank manway. Inside the central work area. * Size specified in PES, but not less than NPS 6 (see Figure 7).
             
 

 

 

A2 Secondary Relief Vacuum Breaker

(Vapor)

*   At center on outer tank roof, branching from inner tank manway. Inside the central work area. * Size specified in PES, but not less than NPS 6 (see Figure 7).
             
 

 

 

 

B Vent

(Vapor)

80 (3)

Min

(See PES)

  At center of outer tank roof, branching from inner tank inner tank manway. The line shall extend 5000 mm beyond the roof area hand rail. See Figure 7. Insulation requirements are stated in para. 5.5.14.

 

 

             
 

 

C Rupture Disc

(Vapor)

150 (6)

Min

  At center of outer tank roof, branching from inner tank inner manway. See Figure 7. Line size shall be equal or greater than for lines A1 and A2.
             
 

 

 

D

 

PBU Pressure controller

(Vapor)

15 (1/2) FNPT coupling From inner tank manway neck. See Figure 7.
             
 

 

 

E Overfill

(Liquid)

50 (2)

Sch 10S

Min.

 

Sch 10S

At maximum liquid level of inner tank and lower part of outer tank. Line shall enter inner tank shell just below the maximum liquid level and project upwards inside the tank to the maximum liquid level (see Figure 1). Line shall be continuously sloped toward the outer tank penetration with a minimum slope of 1 in 4. External termination shall be as shown in Figure 6. The line may locally be run level in the radial direction at the inner and outer tank penetrations.  Line shall be 40S schedule minimum locally at penetration to the inner tank and outer tank.
             
  F Pump Suction Vent 80 (3) Min

Sch 10S

Min.

 

Sch 10S

At top of inner tank. Line shall leave outer tank near bottom of outer shell. See Figures 5.
             
             
 

 

 

G1 Liquid Outlet

(Liquid)

150 (6)

Sch 40S

Min.

 

Sch 40S

At lower part of inner tank sidewall. Line shall leave the outer tank through the outer tank bottom. Line shall be continuously sloped toward the outer tank penetration (see Figure 3).
             
 

 

 

G2 Liquid Outlet

(Liquid)

150 (6)

Sch 40S

Min.

 

Sch 40S

At lower part of inner tank sidewall. Line shall leave the outer tank through the outer tank bottom. Line shall be continuously sloped toward the outer tank penetration (see Figure 3).
             
 

 

 

G3

 

Liquid Outlet

(Liquid)

150 (6)

Sch 40S

Min.

 

Sch 40S

At lower part of inner tank sidewall. Line shall leave the outer tank through the outer tank bottom. Line shall be continuously sloped toward the outer tank penetration (see Figures 3).
             

 

Table 1 (continued)

 

 

 

 

NOZZLE

IDENTIFICATION

LETTER

 

SERVICE

(LIQUID/VAPOR)

 

DN (NPS)

(Inches) & Schedule

END

PREP (Schedule)

 

 

LOCATION

 

 

REMARKS

             
 

 

 

J Fill

(Liquid)

100 (4) or 150 (6)

Sch 10S min.

(See PES for line size)

 

Sch 10S

Through inner shell roof and near bottom of outer shell. Line shall enter inner tank above maximum liquid level and shall extend downward to near tank bottom.

 

Line shall be designed so fill point in inner tank will be at least the greater of 45 degrees or 5 meters from liquid outlets (Nozzles G1, G2, and G3) in the inner tank. This may be accomplished by entering inner tank   at a minimum of the greater of 45 degrees or 5 meters from Nozzles G1, G2, and G3 or by extending the fill line inside the tank to provide an equivalent clearance. This requirement shall be adhered to even if Air Products locates both nozzles adjacent to each other on outer tank. A method of preventing syphon effect shall be provided for the top of the fill line as shown in Figure 10. The fill line shall not impinge directly on the inner tank floor. Line shall be 40S schedule minimum locally at penetration to the inner tank and outer tank penetration plate.
             
  K Trailer Unloading

(Liquid)

40 (1.5)

Sch 10S

min

Sch 10S Through inner shell roof and near bottom of outer shell. Line shall enter inner tank above maximum liquid level. Only required when specified on the PES. See Figure 5.
             
 

 

 

 

M Outer Roof Manway

(Vapor)

**   At top center of outer roof. ** Size by supplier.

Concentric with inner roof manway.

DIN flanges are acceptable.

(See Figure 7).

             
 

 

 

 

N Inner Roof Manway

(Vapor)

800 (32) min   At top center of inner roof. ** Size by supplier.

Concentric with outer roof manway.

(See Figure 7).

             
 

 

 

P Perlite Fill Ports/Emergency Vent ***   On outer roof. *** Quantity and size as required by supplier. One port “P1″ shall be a 20″ manway, equipped with a 20” emergency vent. Set to relieve at 7.5 mbar (3 in H2O). (See Section 6.2 for approved emergency vent models and suppliers.)

 

             
 

 

 

Q Breather Valve 100 (4) min.   On outer roof. Shall be equipped with a breather valve. Setting is 5 mbar (2 in H2O) pressure and 2.5 mbar (1.0 in H2O) vacuum, the over pressure for the vacuum case shall be limited to 5 mbar (2in H2O). (See Section 6.2 for approved emergency vent models and suppliers.)  Tank supplier will size. Also 15 (1/2″) branch from nozzle with bleed valve, Herose7 0135.0400.7906 globe valve, 15 (1/2″) FNPT (Air Products valve designator WXBNGL030TFHE01), or approved equivalent.

 

 

             
  R Annular Space

Purge Inlet

50 (2) min.   Circular perforated header shall run the entire periphery of the annular space. Termination shall be plain end (see Figure 11).
             

 

Table 1 (continued)

 

 

 

 

NOZZLE

IDENTIFICATION

LETTER

 

SERVICE

(LIQUID/VAPOR)

 

DN (NPS

(Inches) & Schedule

END

PREP (Schedule)

 

 

LOCATION

 

 

REMARKS

 
                 
    S Lower Liquid Level

(Liquid)

15 (1/2)

Sch 40S

Min.

 

Sch 40S

From lower part of inner tank sidewall. Line shall leave the outer tank sidewall at approximately the same elevation that it exits the inner tank wall.

 

The line shall include a vertical seal loop in the annular space. The distance of the seal loop from the inner tank wall is to be maximized. External termination shall be as shown in Figure 6.  
                 
    T Upper Liquid Level/PIC Vent Controller (Vapor) 15 (1/2) FNPT coupling From inner tank manway neck. See Figure 7.  
                 
   

 

 

U

 

Vapor Return/P.B. Coil Return

(Vapor)

80 (3)

Sch 10S

Min.

 

Sch 10S

At top of inner tank. Line shall leave outer tank near bottom of outer shell. See Figures 5.  
                 
   

 

 

V1, W1

 

 

Pump Recycle

Associated with G1

(Liquid)

80 (3)

Sch 10S

Min.

 

Sch 10S

At top of inner tank. Lines shall leave outer tank via a multiple-line thermal barrier through the outer tank bottom. See Figure 3. At inner tank nozzles shall be at least the greater of 45 degrees or 5 meters away from Fill Nozzle J. Locally the line schedule to be minimum of 40S where welded to the inner tank and the outer tank multiple line thermal barrier base plate.  
                 
   

 

 

V2, W2

 

 

Pump Recycles

Associated with G2

(Liquid)

80 (3)

Sch 10S

Min.

 

Sch 10S

At top of inner tank. Lines shall leave outer tank via a multiple-line thermal barrier through the outer tank bottom. See Figure 3. At inner tank nozzles shall be at least the greater of 45 degrees or 5 meters away from Fill Nozzle J. Locally the line schedule to be minimum of 40S where welded to the inner tank and the outer tank multiple line thermal barrier base plate.  
                 
   

 

 

V3, W3

 

Pump Recycles

Associated with G3

(Liquid)

80 (3)

Sch 10S

Min.

 

Sch 10S

At top of inner tank. Lines shall leave outer tank via a multiple-line thermal barrier through the outer tank bottom. See Figure 3. At inner tank nozzles shall be at least the greater of 45 degrees or 5 meters away from Fill Nozzle J. Locally the line schedule to be minimum of 40S where welded to the inner tank and the outer tank multiple line thermal barrier base plate.  
                 
   

 

 

X1, Y1

(Only when vertical pump option specified in PES)

Pump Casing Vents

Associated with G1 for vertical pump option only

(Vapor)

50 (2)

Sch 10S

Min.

 

Sch 10S

At top of inner tank. Line shall leave outer tank near bottom of outer shell. See Figures 5. At inner tank nozzles shall be at least the greater of 45 degrees or 5 meters away from Fill Nozzle J. Line shall be 40S schedule minimum locally at penetration to the inner and outer tank penetration plate.  
                 
   

 

 

X2, Y2

(Only when vertical pump option specified in PES)

Pump Casing Vents

Associated with G2 for vertical pump option only

(Vapor)

50 (2)

Sch 10S

Min.

 

Sch 10S

At top of inner tank. Line shall leave outer tank near bottom of outer shell. See Figures 5. At inner tank nozzles shall be at least the greater of 45 degrees or 5 meters away from Fill Nozzle J. Line shall be 40S schedule minimum locally at penetration to the inner and outer tank penetration plate.  
                 
   

 

 

X3, Y3

(Only when vertical pump option specified in PES)

Pump Casing Vents

Associated with G3 for vertical pump option only

(Vapor)

50 (2)

Sch 10S

Min.

 

Sch 10S

At top of inner tank. Line shall leave outer tank near bottom of outer shell. See Figures 5. At inner tank nozzles shall be at least the greater of 45 degrees or 5 meters away from Fill Nozzle J. Line shall be 40S schedule minimum locally at penetration to the inner and outer tank penetration plate.  
               

 

                                                                     Table 2                                                                    

 

Supplier Information Required With Proposal

 

Inner Tank Outer Tank Annular Space Piping
         
General Shell diameter Shell diameter Material  
  Shell height Shell height Schedule  
  Roof shape/radius Roof shape/radius    
  Liquid level N/A    
  Slosh height N/A    
  Material of construction Material of    
    construction    
         
      Cellular glass  
Thickness Roof Roof    
  Shell Shell Type  
  Floor Floor Height  
  Annular plate N/A Interleaving material  
  Compression bar size N/A Volume m3 including required spare  
    Take-out price if cellular glass, supply and delivery is by others. Interleaving material still by tank supplier.

Take-out prices for cellular glass, glass cloth, and inorganic powder. Interleaving material if supply and delivery is by others.

 
Anchors Type Type    
  Quantity Quantity Heat Leak  
  Size Size    
      Calculated value  
Shell Quantity Quantity Guaranteed value

 

 
Stiffeners Size Size Coefficients of thermal  
      conductivity (K) used for all  
Weld Roof Roof insulation materials under  
Joints Shell Shell steady-state conditions  
  Corner Corner Miscellaneous  
  Extent of radiography      
      Ladders or stairway  
         
Relief Devices Type Type    
  Size Size    
  Set pressures Set pressures    
         
Valves Type Type    
  Size Size Other Documentation  
      Overall schedule  
      Preliminary general arrangement  
      List of subcontractors  
      Insulation specification  
      Quality plan (typical)  
      Preliminary manufacturing and erection procedure  
      Assumptions  
      Statement of compliance with Air Products requirement  
      Statement of any exclusions  

 

Figure 1

Tank Schematic, Showing Nozzles

Notes:

 

  1. Nozzles are defined in Table 1.

                                                           Figure 2                                                              

 

Arrangement of Base Insulation

Notes:

 

  1. The use of pieces of cellular glass blocks with plan dimensions less than half a block shall be avoided and never be used at the outside edge.

Figure 3                                                            

 

 

Multiple Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal and Pump Recycle Lines Nozzles (G1, V1, and W1), (G2, V2, and W2),

and (G3, V3, and W3)

Notes:

  1. Foundation slab concrete to have a maximum thickness of 1000 mm.

 

Thermal-barrier foundation plates by tank supplier for installation by others.

 

Dimensions are in millimeters (1 in = 25.4 mm).

Lines V and W to be 40s minimum schedule locally where welded to the penetration base plate (Line G is 40s minimum),

Length of lines G, V and W within thermal sleeve are to be included in the prefabrication scope see Appendix J

                                                                       Figure 4                                                              

 

 

Shroud Plate for Multiple-Line Thermal Barrier in Outer Tank Bottom

 

 

Notes:

 

  1. See Figure 3 for position of attachment to Multiple-Line Thermal Barrier in Outer Tank Bottom.

 

  1. Dimensions are in millimeters (1 in = 25.4 mm).

 

  1. Plate is not symmetrical in the radial direction.

 

 

 

 

 

                                                                        Figure 5                                                            

 

Single Line Thermal Barrier in Outer Tank Sidewall

(Nozzles X1, X2, X3, Y1, Y2, Y3, F, J, K and U)

   

 

Nozzle

Nozzle

Size DN (NPS)

(inches)

Sleeve

Size DN (NPS)

(inches)


“A” Outside Diameter of plate (mm)
  K 40 (1.5) 200 (8) 350
  X1, X2, X3, Y1, Y2, and Y3 50 (2) 200 (8) 350
  F, U 80 (3) 250 (10) 450
  J 100 (4) 300 (12) 450
  J 150 (6) 300 (14) 500

 

Note:  Elevation “E” is specified in Appendix F.

 

Unless indicated otherwise, dimensions are in millimeters (1 in = 25.4 mm).

 

Lines X1, X2, X3, Y1, Y2, and Y3 are omitted when horizontal pump option is specified.

 

All lines to be 40s minimum schedule locally where welded to the penetration plate.

                                                                       Figure 6                                                               

 

Piping Transition Details (Nozzles E and S)

 

 

 

 

 

 

 

Note:

 

  1. Dimensions A and B for Air Products standard tank are stated in Appendix F (Table F1 and Figure F). If required, alternative dimensions A and B would be stated in the PES.

 

  1. All lines to be 40s minimum schedule locally where welded to the penetration plate.

 

                                                                    Figure 7                                                                 

 

Relief Devices Arrangement – Roof Manway M/N

Notes: 

 

  1. Item numbers refer to paragraph numbers in “Notes to Figure 7.”
  2. Dimensions are in millimeters (1 in = 25.4 mm).
  3. Tail pipes for nozzles A1, A2, and C shall be fitted with a mesh basket as shown in Figure 9.
  4. The diameter of the manway is a minimum and may need to be increased to accommodate large size relief devices .

                                                           Notes to Figure 7                                                          

 

  1. All components shall be cleaned according to 4WPI-SW70003.

 

  1. Nozzle A1 shall be fitted with the components* listed below and arranged as shown on Figure 7.

Anderson, Greenwood and Company,** 2 Combined Pressure and Vacuum Relief Valve, pilot-operated with remote pressure pickup extending into inner tank, aluminum body with RF flanges on inlet and FF flanges on outlet, Class 150 drilling according to ASME B16.5 and field-test connection (three way valve). The size of the relief valve will be stated by Air Products in the PES. The model numbers and applicable Air Products specification for the possible sizes of relief valves are as follows:

 

 

  Valve Size Model Number Design  Pressure Specification
  DN (NPS)   bar g (psig)  
  100 (4) x 150 (6) 9390C04ALTAC/SPL 0.138 (2) ET000 MECH 0012
      0.345 (5) ET000 MECH 0013
  150 (6) x 200 (8) 9390C06ALTAC/SPL 0.138 (2) ET000 MECH 0014
      0.345 (5) ET000 MECH 0015
  200 (8) x 250 (10) 9390C08ALVAC/SPL 0.138 (2) ET000 MECH 0016
      0.345 (5) ET000 MECH 0017
  250 (10) x 300 (12) 9390C10ALVAC/SPL 0.138 (2) ET000 MECH 0018
  0.345 (5) ET000 MECH 0019

 

 

 

SPL = “A ½” SS union fitting installed in the sense line, between the field-test connection valve, and, the pilot”.

 

The set pressures of valve shall be the inner tank design pressure as specified in the PES for internal pressure. The actual set pressure for vacuum case will vary between 2.0 bar (0.8 in H2O) and 2.5 mbar (1.0 in H2O) vacuum depending upon valve size and material selection. The actual set pressure values are given in the applicable specification referenced in the above table.

Spool piece, two aluminum or stainless steel, Class 150 RF flanges, with dimensions according to ASME B16.5, welded back-to-back. A 15 (1/2″) FNPT hole shall be drilled and tapped into one flange for bleed valve . A reducer will also be required if an NPS 4 relief valve is specified.

Bleed valves, Herose7 0135.0400.7906. globe valve, 15 (1/2″) FNPT (Air Products valve designator WXBNGL030TFHE01). Line after bleed valve to be run to safe location (a position to avoid operator’s eyes).

Block valve, Neles-Jamesbury8 stainless steel K815W-18-3600HBAS-LEVER (or K818W-18-3600HBAS-LEVER if CE marking is required) or Robinet Danais16 TBT equivalent. The block valves for A1, A2, and C shall be fitted with Smith Flow Control13 locking devices to lock the valve in the fully open position (locking device is not required for B). The Smith Flow Control13 locking devices shall be QL type and use the same key. The key shall be removable only when the valve is locked in the fully open position. This is essential to ensure that only one relief device can be isolated at one time. A total of two keys per tank shall be provided; only one of these will be held at site. The block valves shall have a mechanism to ensure the lever is positively located when moved to the closed position.

Aluminum or stainless steel vent pipes (sized to suit relief valve and rupture disc discharge) with 5‑degree downward slope at end (vents extend over the handrail).

Flange, aluminum or stainless steel, Class 150 RF flange, with dimensions according to ASME B16.5.

 

Notes to Figure 7 (continued)

Stainless steel expansion bellows assembly with stainless steel flange, blind or flat cover connection to the manway pipe.

 

PIC-controlled valve – Butterfly Neles-Jamesbury8  / Globe Samson Controls21. The size and type of the PIC-controlled valve will be stated by Air Products in the PES. The actuator size shall be determined by the control valve supplier. Sizing shall be based on the instrument air supply pressure as stated by Air Products in the PES and the maximum shutoff-differential pressure of 3.45 bar. The positioner input signal will be 4–20 mA. The control valve supplier shall determine the positioner, pilot valve size. Tubing shall be copper and fittings shall be brass Swagelok.

 

  Valve Valve Valve Model Actuator Positioner
  Type Size   Model  
    DN (NPS)      
  Globe 80 (3) Type 3.248, CLASS 150

Body A351 CF8 BWE10S

Extension  21″ Plain Cryo

Characteristic Eq%, Cv 95

Plug/Seat mtl WN 1.4571

Packing PTFE

3277 (FO) 3730-000
    100 (4) Type 3.248, CLASS 150

Body A351 CF8 BWE10S

Extension  22″ Plain Cryo

Characteristic Eq%, Cv 190

Plug/Seat mtl WN 1.4571

Packing PTFE

3277 (FO) 3730-000
    150 (6) Type 3.248, CLASS 150

Body A351 CF8 BWE10S

Extension  27″ Plain Cryo

Characteristic Eq%, Cv 300

Plug / Seat mtl WN 1.4571

Packing PTFE

3277 (FO) 3730-000
           
  Butterfly 80   (3) 3″K815WO-14-36HBAS QPX Series (SO) NE720S/S1A-K
    100 (4) 4″K815WO-16-36HBAS QPX Series (SO) NE720S/S1A-K
  150 (6) 6″K815WO-18-36HBAS QPX Series (SO) NE720S/S1A-K
    200 (8) 8″K815WO-18-36HBAS QPX Series (SO) NE720S/S1A-K

 

Continental9 rupture disc for the size and design pressure stated in the PES to the specification listed below

 

  Size Model Number Design Pressure Specification
  DN (NPS)   bar g (psig)  
  150 (6) 6” R-C-CDC-V (FS) 0.345 (5) ET000 MECH 0007
  200 (8) 8” R-C-CDC-V (FS) 0.138 (2) ET000 MECH 0006
  200 (8) 8” R-C-CDC-V (FS) 0.345 (5) ET000 MECH 0008
  250 (10) 10” R-C-CDC-V (FS) 0.138 (2) ET000 MECH 0004
  250 (10) 10” R-C-CDC-V (FS) 0.345 (5) ET000 MECH 0005

 

The rupture disc size shall never be less than that of the relief valve size specified.

Minimum disc size for design pressure 0.138 bar g (2 psig) shall be 200 (8″).

Aluminum or stainless steel reducer, if required.

 

Flange, aluminum or stainless steel, Class 150 FF flange, with dimensions according to ASME B16.5. A 15 (1/2″) FNPT hole shall be drilled and tapped into the flange for bleed valve ; this may be in if fitted.

Baffle plate from above Nozzle B and extending into inner tank. The baffle isolates a segment of the manway for flow to Nozzle B. This may take the form of a flat plate or channel section. The baffle plate shall be continuously welded to the inside of the manway and fitted with a welded top cap. The cross section enclosed by the baffle plate shall be equal or greater in area than that of Nozzle B.

 

Pilot line – ½” Stainless steel tubing with tubing adapters (double ferrule compression by MNPT) at each end

 

  1. The relief device arrangement shall be orientated such that no platforms or walkways are located within 3 meters (10 ft) of a radial line from any relief device to the edge of the outer tank.

 

Notes:  *   Paragraph numbers within circles under “B” refer to item numbers in Figure 7.

            ** Superscript numbers refer to manufacturer’s listing in Appendix E.

 

 

Figure 8

Ice Catcher Detail for Vent Line

 

 

 

 

Note:

 

  1. Size and clearances are minimum dimensions.

Figure 9

Mesh Basket-Protection Against Debris Accumulation

 

 

 

 

 

 

 

 

 

 

 

Notes:

 

  1. To be fitted to tail pipes of nozzle A1, A2, and C.
  2. Not to be fitted to tail pipe of nozzle B.
  3. All materials shall be stainless steel.
  4. Tether length shall permit removal mesh basket from vent pipe.

 

 

 

Figure 10

Details of Syphon Breaker

 

  Nozzle J Size A

DN (NPS)

B

DN (NPS)

C

DN (NPS)

  100 (4) 150 (6) 350 (14)
  150 (6) 200 (8) 400 (16)

 

Note:

  1. The fill line shall not impinge directly on the inner tank floor.

                                                                       Figure 11                                                           

 

Nitrogen Purge Arrangement and Wrapper Detail – (Nozzle R)

Note:

  1. Dimensions are in millimeters (1 in = 25.4 mm).

                                                                    

Figure 12                                                             

 

Acceptable Arrangement for Elimination of Outer Tank Bottom

                                                                     Appendix A                                                                 

 

Minimum Level of Inspection

 

Inspection will include the following for the inner tank and piping:

 

A1.       Examine all pressure part materials. Check certificates against identification marking on materials. Ensure that material is free from defects and that thicknesses are according to the design requirements.

 

A2.       Ensure that the certified material properties are according to the requirements of the specification and any additional requirements imposed by the design code or purchase order.

 

A3.       Approve weld procedures to be used during fabrication. Witness weld procedure qualification tests for weld procedures to be used that Air Products have not previously approved. The witness shall include impact testing.

 

A4.       Review welder performance qualification certificates. Witness new tests if the welder performance qualification certificates are out of date or are not applicable or have not been witnessed by an acceptable authority.

 

A5.       Examine shell and roof plates after forming for damage and fit-up.

 

A6.       Examine edges of openings in shell and roof plates for nozzles; ensure that these are free from laminations and other defects.

 

A7.       Ensure correct weld-seam setups before welding including edge preparation, alignment of plates, alignment of pipe welds, nozzle-to-shell setups and the weld setups of the significant structural components (for example, support attachments).

 

A8.       Check that dimensional accuracy is according to code requirements and Appendix K.

 

A9.       Check compliance of nondestructive examination procedures with ASME BPVC, Section V.

 

A10.    Visually examine all welds and interpret radiographs.

 

A11.    Witness vacuum box testing.

 

A12.    Witness dye-penetrant crack detection.

 

A13.    Inspect installation of base insulation system.

 

A14.    Check clearance between piping and platform steelwork.

 

A15.    Examine installation of bellows units at the top of the tank (inner tank manway with nozzles A1, A2, B, C, and nozzles for internal shutoff actuators if fitted).

 

A16.    When internal shutoff valves are fitted, inspect the installation and check for smooth operation of the shutoff valves, cables, and actuators.

 

A17.    Witness the hydro-pneumatic and associated tests in the inner tank according to design code.

 

A18.    Measure tank settlement (at a minimum of 12 equally spaced locations around the tank circumference) during the hydro-pneumatic test. The report shall be forwarded to the Air Products specifying engineer.

 

A19.    Witness pressure and leak tests on the interspace piping.

 

A20.    Check provision and stamping of nameplate.

 

A21.    Check that log-book documentation is complete and issue final certificate of construction.

 

Appendix B

 

Nondestructive Testing

 

B1.  Inner Tank    
     
        Anchor strap attachments to shell to reinforcing pad and reinforcing pad to shell   Dye penetration crack detection before and after hydro-pneumatic test.
     
        Bottom annular plate butt-welds   Radiography as required by code. Vacuum box before and after hydro-pneumatic test.
     
        Butt-welds in stiffening rings, and compression ring welds   As required by code.
     
        Compression ring to shell-welds   Dye-penetration crack detection inside and outside.
     
        Lap joints in bottom plates   Vacuum box before and after hydro-pneumatic test.
     
        Lap joints in roof plates   Vacuum box. For LOX tanks, before welding second side.
     
        Nozzle-to-shell welds, stiffening rings, and other attachments   Dye-penetration crack detection.
     
        Shell-to-bottom corner joint   Dye-penetration crack detection inside and outside as required by code.
     
        Shell butt-welds   As required by code.
     
B2.  Outer Tank    
     
        Lap joints in bottom plates (if fitted)   Vacuum box.
     
        Lap joints in roof plates, shell butt-welds, shell-to-bottom corner joint   Vacuum box, or leak test using soap solution executed during pneumatic test.
     
        Penetrations, roof-to-shell joint   Leak test using soap solution executed during pneumatic test.
     
B3.  Interspace Liquid Piping (Table 1 defines liquid/vapor lines)    
     
        Circumferential joints   100% radiography.
     
        Thermal barrier base/end plate to pipe weld   Internal visual inspection for burn through by boroscope
     
B4.  Interspace Vapor Piping (Table 1 defines liquid/vapor lines)    
     
        Circumferential joints – Prefabricated pipe spools, shop pressure tested   30% of joints shall be 100% radiography+

 

     
        Circumferential joints – Field   30% of joints shall be 100% radiography+
     
        Thermal barrier base/end plate to pipe weld   Internal visual inspection for burn through by boroscope
     
 

 

   
B5.  Anchor Straps    
     
        Any load-carrying butt-welded joints   100% radiography.
     
        Any load-carrying fillet-welds   100% dye penetrant crack detection.

 

+ 100% of welds on oxygen tank pipework shall be visually examined to ensure that the internal root profile is smooth, free from overpenetration, irregular profile, weld splatter, excessive oxide formations, or other imperfections. If the root pass cannot be visually examined, that weld shall be subjected to 100% radiographic examination.
Appendix C                                                            

 

Foundation Loading Data Requirements

 
Load       Loading Condition
No. Description Units Direction Erection Test (Full) Design (Full)
1 Inner Tank Dead Weight N/m Down      
2 Outer Tank Dead Weight N/m Down      
3 Live Load (Snow, etc.) N/m Down      
4 Uplift-Outer Tank Pressure N/m Up      
5 Wind (Outer Shell Only) N/m Up & Down      
6 Wind (Roof Only) N/m Up      
7 Earthquake Load Per Anchor (Inner Tank) kN Up      
8 Inner Tank Bottom Plate Weight kN/m2 Down      
9 Outer Tank Bottom Plate Weight kN/m2 Down      
10 Insulation Between Bottoms kN/m2 Down      
11 Perlite (Annular Space) kN/m2 Down      
12 Liquid Pressure kN/m2 Down      
13 Gas Pressure (Inner) kN/m2 Down      
14 Annular Space Pressure kN/m2 Down      
15 Wind Moment Nm      
16 Wind Shear kN Horizontal      
17 Earthquake Moment (Inner Tank) Nm      
18 Earthquake Moment (Outer Tank) Nm      
19 Earthquake Shear (Inner Tank) kN Horizontal      
20 Earthquake Shear (Outer Tank) kN Horizontal      
21 * Inner Tank Load Per Anchor kN Up      
22 * Outer Tank Load Per Anchor kN Up      
23 Perlite (Inner Tank Roof) N/m Down      
24 Uplift-Inner Tank Pressure N/m Up      
25 Earthquake Load Per Anchor (Outer Tank) kN Up      

* Excluding Earthquake Loads

 

Where:  N = Newtons

kN = kilo Newtons

m = meter

                                                                 Appendix D                                                               

 

External Pressure Loading on Storage Tanks,

Stiffener Ring Spacing, and Sizing

 

D1.      Notation

 

Do   =    Outside diameter of tank, mm (in)

Ro   =    Outside radius of tank, mm (in)

E     =    Modulus of elasticity, N/mm2 (psi)

F     =    Factor of Safety = 2

Fa    =    Allowable stress, N/mm2 (psi)

h     =    Height of tank between end stiffeners, mm (in)

N     =    Number of complete waves into which stiffener ring will buckle

t1    =    Weighted average thickness of shell between end stiffeners, mm (in)

t      =    Minimum thickness of cylindrical plate; or for determining stiffener spacing, average thickness of unsupported shell between stiffeners; or for short spans, thickness of middle quarter of span, mm (in)

P     =    External pressure, N/mm2 (psi)

Ls    =    Half distance from center of stiffener to next stiffener or line of support on one side plus half distance to next stiffener or line of support on other side mm (in)

Is    =    Moment of inertia of combined ring-shell section about its neutral axis parallel to cylinder axis, mm4 (in4)

As   =    Cross-sectional area of stiffener, mm2, (in2)

=    Poisson’s ratio = 0.3

 

 

D2.      Stiffener Rings

Required Spacing of Stiffener Rings

 

(1)

 

 

Formula (1) does not apply if the resulting spacing Ls is less than . The circumferential stress in the shell alone, not including the stiffeners, shall not exceed the allowable working stress in compression.

 

The external pressure varies from a lower value at an upper point on the shell to a maximum at the shell-to-bottom junction. For this triangular radial loading, determination of the first lower unsupported span Ls1 shall be based on the pressure at the bottom. This locates the first stiffener above the bottom. Then the next span procedure Ls2 shall be based on the pressure at the first stiffener. This procedure shall be repeated up the shell. For each span, the thickness shall be assumed as the thickness of the middle quarter of the span or the average thickness of the plates in the span.

 

Appendix D (continued)

 

 

The moment of inertia for the stiffeners shall be at least:

                                                                                                                       (2)

 

 

In equation (2), computation of Is provided may include a portion of the shell equivalent to the lesser of

1.1 or the area of the stiffener.

 

 

where

(3)

 

 

The stiffeners must also satisfy the following requirement for minimum cross-sectional area:

 

 

(4)

 

 

Where Fa shall be taken as the allowable design stress from tank design code.

In determination of As, a width equal to 0.78  of the available shell each side of the stiffener shall be included in the composite area. To ensure a normal-size stiffener, in no case shall the area of the stiffener alone be less than half the required area.

 

                                                                    Appendix E                                                            

 

Material Manufacturer Listing

 

            The following is a listing of acceptable material manufacturers. The Supplier may propose alternate manufacturers for Air Products approval.

 

  1. Flexitallic Inc., 6915, Highway 225, Deer Park, TX 77536

 

  1. Anderson, Greenwood & Company, P.O. Box 1097-TR, Bellaire, TX 77401

 

  1. Foamglas – Pittsburgh Corning Corp., 800 Presque Drive, Pittsburgh, PA 15239

 

  1. Kaowool – Babcock & Wilcox Co., A McDermott Company, 2102 Old Savannah Road, Augusta, GA 30093

 

  1. Alnor Instrument Co., 7555-T N. Linder Ave., Skokie, IL 60077

 

  1. L and J Technologies (Shand & Jurs), 5911 Butterfield Road, Hillside, IL 60162

 

  1. Herose GMBH, ArmaturenUnd Metalle, Elly-heuss-Knapp-Str.12, D-23843 Bad Oldesloe, Postfach: 1561, Germany.

 

  1. Neles-Jamesbury, Inc., 640 Lincoln Street, Worcester, MA 01615

 

  1. Continental Disc Corp., 4103 Riverside N.W., Kansas City, MO 64150

 

  1. Rockwool Ltd., Pencoed, Bridgend, Mid Glamorgan, CF35 6NY. UK

 

  1. Whessoe Varec Ltd., Heighington Lane, Newton Aycliffe, Co Durham, DL5 6XZ. UK

 

  1. Marglass Ltd., Westbury, Sherbourne, DT9 3RB. UK

 

  1. Smith Flow Control Limited, 6 Waterside Business Park, Eastways industrial Estate, Witham, Essex CM8 3YQ. UK

 

  1. Motherwell Control Systems Ltd., Neils Road, St. Helens, Mersey, WA9 4TH. UK

 

  1. Interglas Ltd., Westbury, Sherbourne, DT9 3RB. UK

 

  1. AMRI (Robinet Danais), 96, rue des Alpes, SILIC 594, 94663 RUNGIS CEDEX, FRANCE

 

  1. JPS Glass Fabric, PO Box 260, Slater, SC 29683

 

  1. Groth Corporation, 1202 Hahlo, P.O. Box 15293, Houston, TX 77220-5293

  1. A G Marvac Ltd., 24-25 Melford Court, Hardwick Grange, Woolstone, Warrington WA1 4RZ. UK

 

  1. Cell-U-Foam, P.O. Box 99, 810F/M 521, Fresno, TX 77545

21.       Samson Controls (London) Ltd, Perrywood Business Park, Redhill, Surrey RH1 5JQ. UK

 

  1. Zhejiang Zhenshen Cold Insulation Technology Co., Ltd (ZES)., Wangdian Town, Xiuzhou Area, Jiaxing City, Zhejiang, PRC

 

  1. Shanghai Acmetex Co., Ltd. Room101, No.88, Branch Lane 2, Lane 1028, XiuYan Road, Shanghai, China XiuYan Road, Shanghai, 201315, PRC

 

  1. Lupi Petrotecna Avda. Filipinas, 38 – 28003 Madrid Spain

                                                        Appendix F                                                            

 

Air Products Standard Tank Dimensions, Nozzle Orientations, and Elevations

 

            Suppliers are encouraged to submit designs which have been pre-engineered or built. If the supplier does not have a tank design with the volume as required by the PES, the following shall be followed.

 

F1.       This appendix defines a range of standard tanks that Air Products intends to use on the majority of projects.

 

F2.       Standard tanks will be specified by using the PES that will define the tank nominal capacity, product, any options such as relief device sizes, required number of liquid outlet lines, and pump configuration (see paragraph 5.3.12) or variations to the main body of this specification.

 

F3.       Any items not specified in this appendix or the PES shall be according to the main body of this specification.

 

F4.       Table F1 and Figure F1 define the interface points of the tanks.

 

F5.       Heat leak calculations for standard tanks shall be executed at standard ambient conditions as specified in paragraph 5.5.1 and demonstrate that the required maximum percentage daily loss of product stated in paragraph 5.5.1 is not exceeded. The supplier might be asked to calculate the heat leak for specific ambient conditions for a particular project, but not required to achieve the required maximum percentage daily loss of product stated in paragraph 5.5.1.

 

Table F1

 

Standard Tank Interface Points

   

Nominal Tank Capacity

 

A

Outer Tank Inside Diameter

 

B

Liquid Outlet Nozzles Radial Location

C

Side Exit Nozzles E, J, R, U, X, Y Standout

 

D

Side Exit Nozzle S

Standout

  M3 Min. Max. Min. Max. (A/2 max + 700) (A/2 max + 150)  
          700 11 500 12 000 5 250 5 625         6 700          6 150  
          900 11 900 12 600 5 400 5 925         7 000          6 450  
       1 350 13 050 14 750 6 100 7 000         8 075          7 525  
       1 800 14 800 16 400 7 000 7 825         8 900          8 350  
       2 250 16 350 17 150 7 500 8 200         9 275          8 725  
       2 700 17 450 17 850 8 150 8 550         9 625          9 075  
       3 150 18 700 19 450 8 800 9 350       10 425          9 875  
       3 600 20 000 22 000 9 450 10 625       11 700        11 150  
       4 500 21 700 23 000 10 300 11 125       12 200        11 650  
       5 400 22 500 23 500 10 700 11 375       12 450        11 900  
       6 300 23 800 24 800 11 350 12 025       13 100        12 550  

 

Notes:

 

  1. All linear dimensions are in mm.

 

  1. The angle q of the relief-device arrangement relative to 0 degrees in the tank coordinate system (see Figure F1) will be specified in the PES.

 

  1. Nominal tank capacity is the minimum releasable volume to satisfy the requirements of paragraphs 5.2.7 and 5.2.9 for the worst seismic design condition, Seismic Zone 4. The tank capacity shall be increased for lower seismic requirement by moving the position of the tank overfill (E).

Appendix F (continued)

 

  1. For each tank nominal capacity, a range for dimensions A and B is allowed. This enables suppliers to configure tanks to suit an economic shell plate arrangement. Once a tank supplier has provided a tank, dimensions A and B will be fixed for all future tanks of that nominal capacity purchased from that supplier.

 

  1. Dimensions C and D are fixed.

 

  1. Suppliers may offer tanks of capacities up to 110% of the nominal capacity.

 

  1. The supplier shall select dimensions A and B to enable the multiple-line thermal barriers to be positioned in the annular space, while meeting the minimum cellular glass extension beyond the inner-tank, annular-plate requirements for Figure 2 and paragraph 5.5.4. The cellular glass shall not cover the thermal-barrier opening, but may be located above the hole in the concrete.

 

  1. Dimensions A and B must be selected to permit the thermal-barrier plates to be located as shown in Figure 3. The outer tank wall must not be located above the hole in the concrete.

 

  1. The tanks up to and including 4 500 m3 nominal capacity shall be geometrically identical for LOX and LIN. Tanks with nominal capacity greater than 4 500 m3 shall be used for only LIN storage; therefore, LOX need not be considered when setting these tank geometries.

 

  1. All tank geometries including sloshing allowance shall be suitable for Design Spectral Response Accelerations SS = 1.5(g) and S1 = 0.6(g) using the method stated in Appendix Q of this specification.

 

When paragraph 5.2.7 requires a greater volume of freeboard than for seismic sloshing, a standard tank, but with a reduced releasable capacity may be offered.

 

 

  1. All tanks shall be designed for a design wind velocity of 54 m/s (120 mph) [3 second gust]. Design loads shall be developed by methods outlined in the latest edition of ASCE 7 using an Importance Factor of 1.0, Risk Category II, an Exposure Factor “C,” and a Gust Effect Factor “G” of 0.85.

 

  1. Internal shutoff valves are not fitted as standard. When positioning liquid-line penetrations to the inner tank, consideration shall be given to the possibility that internal shutoff valves might be required (see Appendix M paragraph M1). Therefore all standard tanks shall be according to the requirement of paragraph M2.

 

  1. Suppliers must consider all possible options listed in PES when engineering the tank configuration and layout for the first time. This shall be executed for all lines fitted, and any size options shall be maximized. The layout must not be option dependent. This will minimize any rework for repeat orders with different options specified.

 

  1. Supplier’s documentation shall be presented in a manner that minimizes work that results from the possible options listed in the PES.

 

  1. The liquid fill line J will be DN 100 (NPS 4) for LIN tanks, but may be DN 100 (NPS 4) or DN 150 (NPS 6) for LOX tanks. The required fill line size will be stated in the PES.

 

  1. The height of the syphon breaker (top of reducer shown in Figure 10) shall be set at the maximum liquid level for seismic zone 0 (no seismic requirement). This position shall not vary with seismic zone.

 

  1. The line pressure considered in the piping analysis shall 3.45 bar g this includes the liquid static head plus the gas design pressure.

 

 

Figure F1                                                            

 

Air Products Standard Tank Arrangement

       Note:  For dimensions see Table F1.

Appendix G    

Alternative Line Thermal Barrier Configurations – Outer Tank Bottom Exit

 

When indicated in the PES, alternative single or multiple line thermal barriers in outer tank bottom shall be used. The required line/nozzle designation, line sizes, line service, and line spacing will be stated in the PES.

Figure G1

Single Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal

 

 

 

Figure G2

Two Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal

Figure G3

Three Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal and

Pump Recycle Lines Nozzles

 

Figure G4

Four Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal and

Pump Recycle Lines Nozzles

 

The shroud plate for multiple-line thermal barrier shown in Figure 4 is required.

Figure G5

Four Line Thermal Barrier in Outer Tank Bottom Liquid Withdrawal and

Pump Recycle Lines Nozzles (G1A, G1B, V1, and W1), (G2A, G2B, V2, and W2),

and (G3A, G3B, V3, and W3)

 

 

 

The details shown in Figure G5 replace the details shown in Figure 3. The liquid withdrawal line being modified to include A and B suffixes (for example, G1 is replaced by line G1A and G1B.)

 

The shroud plate for multiple-line thermal barrier shown in Figure 4 is required.

 

 

Appendix H

Alternative Non-Standard Tank Configuration

Thermal Barriers – Outer Tank Sidewall Exit

 

H1.      When stated in the PES, liquid outlet lines (G1, G2, and G3) and pump recycle lines (V1, V2, V3, W1, W2, W3) will require to pass through the outer tank shell instead of through outer tank bottom and elevated foundation base. The required alternative thermal barrier arrangement will be stated in the PES and shall either be single line penetration as shown in Figure H1 or multiple line penetration as shown in Figure H2.

 

Figure H1

Single Line Thermal Barrier in Outer Tank Sidewall

(Nozzles G1, G2, G3, V1, V2, V3, W1, W2, W3)

   

 

Nozzle

Nozzle

Size DN (NPS)

(inches)

Sleeve

Size DN (NPS)

(inches)


“A” Outside Diameter of plate (mm)
  G1, G2, and G3 150 (6) 300 (12) 450
  V1, V2, V3, W1, W2, and W3 80 (3) 250 (10) 450

 

Note:  Elevation “E” will be specified by Air Products at a later date (for Air Products’ standard tank, see Appendix F).

 

           Unless indicated otherwise, dimensions are in millimeters (1 in = 25.4 mm).

 

Figure H2

Multiple Line Thermal Barrier in Outer Tank Sidewall

(Nozzles F, G1, G2, G3, F, J, K, U, V1, V2, V3, W1, W2, W3, X1, X2, X3, Y1, Y2, and Y3)

 

 

 

 

 

 

Notes:

 

  1. Air Products will advise the supplier of line elevations and final cut line standouts at a later date.

 

  1. Dimensions are in millimeters (1 in = 25.4 mm).

 

  1. Lines X1, X2, X3, Y1, Y2, and Y3 are omitted when horizontal pump option is specified.

 

 

 

 

Appendix I

Pressure Testing

 

I1.       Pressure testing of the inner tank shall be according to the design code. Additionally a foundation uplift and anchorage check shall be made by applying air pressure equal to the design pressure to the empty tank.

 

I2.       During pressure testing, the inner tank must be protected by an automatic overpressure safety device. Two acceptable arrangements are shown in Figures I1 and I2. The supplier shall state the specific test setup in the proposal. Any deviation from these test requirements requires Air Products approval before it is used.

 

I3.       During pneumatic pressure testing, a minimum clearance of 10 m (30 ft) shall be roped off around the tank for personnel protection.

 

I4.       The erector shall provide the supplier with the analysis of the water available at the site for testing. If the erector proposes to add chemicals to the test water, the erector must accept responsibility for the disposal of the test water and provide a procedure for this. The pH of the test water shall be between 6 and 7, and its chloride content shall not exceed 50 parts per million (ppm) by volume. All residual water containing more than 25 ppm chlorides shall be mopped up after the equipment is drained. When this is not possible, the equipment shall be flushed with cold condensate or demineralized water until the residual chloride level is less than 25 ppm.

 

I5.       The erector shall ensure that air used in the hydro-pneumatic test is free of hydrocarbons, grease, and any foreign particles.

 

I6.       When piping welds are concealed in the cellular glass under the tank floor, the erector shall either test these welds before installing the line or offer an alternative procedure for checking the leak tightness of these welds. The number of welds concealed in the cellular glass shall be kept to a minimum.

 

I7.       After satisfactory completion of testing, no welding shall be permitted on the tank or piping without obtaining the written approval of Air Products before any work is done.

 

I8.       Once the outer tank is closed off and sealed, the breather valve must be operational at all times to protect against damage to the tank resulting from atmospheric pressure changes.

 

I9.       The operation of inner tank combined pressure/vacuum relief valves (nozzle A1 and A2) shall be checked

 

I10.     Pressure testing of the outer tank shall be according to the design code

 

I11.     The operation of outer tank combined pressure/vacuum relief valve (nozzle Q) shall be checked

 

           

 

 

                                                                     Figure I1                                                             

 

Schematic of Hydro-Pneumatic Test Alternate #1

 

 

 

 

 

 

 

Notes:

 

  1. Install a water column as an automatic pressure relief device. The height of the water column shall correspond to a pressure of 35 mbar (1/2 psi) above test pressure. The vent size shall be DN 100 (NPS 4) minimum and shall be connected to nozzle “J.”

 

  1. Monitor the tank pressure via a manometer at nozzle “U.” The size of this connection is DN 80 (NPS 3). Two pressure gauges may be substituted for the manometer; a single pressure gauge is not acceptable.

 

  1. Compressor discharge shall be connected to nozzle “E” with a provision for emergency shutoff. The size of nozzle “E” is DN 50 (NPS 2). Air shall be brought in through a line size no larger than DN 50 (NPS 2).

 

                                                                    Figure I2                                                               

 

Schematic of Hydro-Pneumatic Test Alternate #2

 

 

 

 

Notes:

 

  1. Install a rupture disc or a pressure relief valve on nozzle “A2.” The size of safety device shall be DN 100 (NPS 4) minimum, and the set pressure shall be 70 mbar (1 psi) above test pressure.

 

  1. Monitor the tank pressure via a manometer at nozzle “U.” The size of this connection is DN 80 (NPS 3). Two pressure gauges may be substituted for the manometer; a single pressure gauge is not acceptable.

 

  1. Compressor discharge shall be connected to nozzle “E” with a provision for emergency shutoff. The size of nozzle “E” is DN 50 (NPS 2). Air shall be brought in through a line size no larger than DN 50 (NPS 2).

Appendix J

Shop Fabrication

J1.       The prefabrication work shall comprise the following:

 

Nozzle assemblies for the inner tank with flexible connections, stiffener rings for inner and outer tanks in segments with edges prepared for welding, piping spools for annular space piping fully inspected and pressure tested, cleaned, and capped to retain the cleanliness.

 

Tank-bottom-penetration, stainless steel thermal barriers, including dry-air-purge systems. This shall include the lengths of pipe within the thermal barriers.

 

The welding of the pipe spools within the thermal barriers to the thermal barrier bottom/end plates. (The pressure test of those piping spools shall be carried out after welding to the bottom/end plates.)

 

Shell plates cut to shape, rolled, and pressed for the inner and outer tank with edges prepared for welding.

 

Carbon steel, outer-tank shell plates, roof plates and floor plates sandblasted and primed painted on both surfaces, except at edges.

 

Annular plates for inner-tank-bottom cut to shape and edges prepared for welding.

 

Anchor-strap assemblies for the inner tank, including keeper brackets and holding bars. Straps may be single piece or two pieces and have weld preparations as required.

 

Roof plates cut to size and pressed.

 

Any special tooling or jacking equipment required for tank erection. This equipment is included in the supplier’s scope even if the supplier is not the tank erector.

 

Stairs, ladders, walkway, and platforms shall be prefabricated in transportable assemblies. Bracing may be provided loose and field cut to suit.

 

J2.       All prefabricated pieces shall be matched, marked, and packaged to follow erection sequence.

Appendix K

Field Fabrication

 

K1.       Field fabrication shall be performed according to the PES and the purchase order.

 

K2.       Inner-Tank-Fabrication Tolerances:  As a minimum, inner-tank-fabrication tolerances shall as follows:

 

K3.       Cylindrical Sidewalls:  See API 620, paragraphs 6.5 and Q.3.9.3.

 

               Plumbness:  The maximum out-of-plumbness between the top and bottom of the shell shall not exceed 1/200 of the total tank height. Out-of-plumb between adjacent shell courses shall not exceed 1/200 (see Figures K1 and K2).

 

               Diameter:  The difference between maximum and minimum diameters, measured at any section shall not exceed 1% of the average diameter or 305 mm (12 in), whichever is less.

 

               Radius:  The maximum tolerance on shell radius, measured at 305 mm (12 in) above the shell-to-floor corner joint, shall not exceed 19 mm (3/4 in) (see API 620, Table Q.6).

 

               Local Deviations:  Peaking, banding, flat spots, and weld distortion.

 

   Using a horizontal sweep board 1000 mm (36 in) long shaped to the tank radius, the peaking at weld joints shall not exceed 13 mm (1/2 in). A sweep board is required for each different tank radius (see Figure K3).

 

   Using a 1000 mm (36 in) long straight edge, the banding at weld joints shall not exceed 13 mm (1/2 in) (see Figure K4).

 

K4.       Double Curvature Roofs:  Each roof will require its own templates (sweep board) for both directions of curvature. The finished surface shall not deviate outside the correct shape by more than 1.25% of the diameter, nor more than 0.625% of the diameter inside the correct shape. The reference diameter is the inside diameter of the roof (see API 620, paragraph 6.5.8).

 

K5.       Flat Floors:  Generally, the floors shall be in contact with the support surface below. High points in the lower plate of 2-plate lap joints and within 100 mm (4 in) of these joints shall not be more than 13 mm (1/2 in) above the support surface below. Similarly high points in the upper plate joints shall not be more than 25 mm (1 in) above the support surface below. Similarly high points in the upper plate of 3-plate lap joints and within 100 mm (4 in) of these joints shall not be more than 25 mm (1 in) above the support surface below. This is not specifically addressed by API 620. Welding of the tank floors shall be sequenced to minimize distortion.

 

K6.       Alignment of Plates:  The edges of all plates up to 6.35 mm (1/4 in) may have a maximum offset of 1.6 mm (1/16 in). For plates over 6.35 mm (1/4 in), maximum offset of edges shall be 3.18 mm (1/8 in) or 25% of plate thickness, whichever is smaller (see API 620, paragraph 6.14).

 

K7.       Weld Reinforcement:  All butt-welds may be built up to ensure full penetration and filling. The maximum extra weld metal thickness shall not exceed 2.4 mm (3/32 in) on vertical joints and 3.2 mm (1/8 in) on horizontal joints (see API 620, paragraph 6.12 and table 6-3).

 

K8.       Weld Finish:  All welds shall merge smoothly into the plate. The maximum permissible undercut is 0.4 mm (1/64 in) on vertical joints and 0.8 mm (1/32 in) on horizontal joints (see API 620, paragraph 6.13).

 

K9.       The supplier shall provide an erection procedure.

 

K10.    The erector shall provide all labor, materials, and services necessary and incidental to the completion of the work.

K11.    The proposed lay-down area will be shown by Air Products in the PES.

 

K12.    The erector shall provide Air Products with the résumé/curriculum vitae of the proposed site superintendent three months before starting construction at site.

 

K13.    The erector shall advise, at the bid stage, the element of the work to be subcontracted.

 

K14.    The erector’s operation shall not interfere with any other construction work that might be going on around the tank. If the tank is to be erected inside an existing operating facility, a safety checklist shall be agreed between erector and Air Products before work begins.

 

K15.    During site erection, the erector shall ensure that the partially completed tank is stable at the design wind speed.

 

K16.    Any leveling, shimming, or grouting of the tank base shall be executed by the erector.

 

K17.    The erector shall seal the edge of the outer tank base with mastic (silicon sealant). The erector shall supply the mastic.

K18.    The tank supplier shall ensure that adequate precautions are taken to prevent overpressurization of the tank annular space during perlite filling. A perlite installation procedure shall be provided that includes those precautions. That document shall be used by the party executing perlite filling.

 

K19.    The outer tank breather valve on Nozzle Q must be replaced with an open gooseneck pipe during perlite filling. The emergency vent P1 must be operational during perlite filling. The tank supplier may also consider pressurizing the inner tank with nitrogen and maintaining it at 0.069 bar g (1 psig) during perlite filling.

Figure K1

Total Out-of-Plumb

Maximum t = h/200

 

 

 

 

 

 

 

 

                                                                      Figure K2                                                         

 

Out-of-Plumb of One Shell Course

Relative to Another,

Maximum = hs / 200

                                                                  Figure K3                                                                

 

“Peaking” Weld Distortion of a

Vertical Seam – Can Be In or Out

 

Shell Plan

 

 

                                                                      Figure K4                                                         

 

“Banding” Weld Distortion of a

Horizontal Seam – Can Be In or Out

 

Shell Elevation

Appendix L

Additional Requirements for Liquid Lines Exiting Inner Tank via Bottom

 

L1.           This appendix may only be used with Air Products prior agreement

 

L2.           This appendix is only applicable for liquid withdrawal lines that exit the inner tank bottom.

 

L3.           Lines shall exit the outer tank base as near to the outer tank sidewall as possible, but not in the annular plate.

 

L4.           The liquid withdrawal lines shall be run through the cellular glass base insulation as high as possible to minimize thermal movement of the vertical pipe section.

 

L5.           Horizontal channels for pipework shall run inside stainless steel box sections designed to fully support the inner tank floor loading (see Figure L1). The pipe shall be centralized in the stainless steel box sections to permit thermal movement.

 

L6.           The height of the stainless steel box sections should equal an exact number of layers of cellular glass blocks.

 

L7.           Mineral Wool (ceramic fiber) insulation shall be installed as indicated in Figure L1. The mineral wool insulation shall be loose packed to permit pipe movement.

 

L8.           A pressure test of the section of liquid line that will be run in cellular glass base insulation needs to be completed before installation.

 

L9.           Vortex breakers shall be fitted to lines that exit via the tank bottom.

 

L10.         The number of welds concealed in the cellular glass shall be kept to a minimum.

 

Figure L1 

Liquid Outlet Through Base Insulation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appendix M

Tanks Requiring Internal Emergency Shut-off Valves

 

 

M1.      When stated in the PES, internal shutoff valves and actuators shall be provided according to 4WEQ-1526. Possible reasons for requiring are internal shutoff valves are:

 

  • Local regulations
  • Codes
  • The approval authority
  • Liquid withdrawal lines G1, G2, and G3 exit through the outer tank side wall

 

M2.      The minimum distance between internal shutoff valves shall be 3000 mm (10 ft).

 

M3.      Access to roof mounted actuators shall be provided.

 

 

 

Appendix N

Tank Certificates

 

A certificate shall be completed for each tank.

Manufacturer’s (Erector) Tank Certificate

 

LP Storage Tank Tag Number ________________________

 

Project                                          ________________________

 

WE CERTIFY that the design, materials, construction, and workmanship of this low-pressure tank conforms to the requirements of:

API 620 (state editions and addendum), Design and Construction of Large, Welded, Low-pressure Storage Tanks

4WEQ-1516 (state revision) Field-Erected, Flat-Bottom, LOX and LIN Storage Tanks including Appendix Q and Appendix L.

Project Equipment Specification (State document number and revision)

 

Date___________________ Signed _________________________ by  _________________

(Signed by the Erector/Manufacturer)

                                                  Erector / Manufacturer name and address

 

I have inspected the tank described in the Manufacturer’s report (XXXXXXX), and state that to the best of my knowledge, the Manufacturer has constructed this tank in accordance with the applicable sections of API 620.

The tank was inspected and subjected to a test of ____________  mbar gauge.

 

 

Date___________________ Signed _________________________ by  _________________

(Signed by the Inspector)

Inspection body name and address

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If the tank Manufacturer (Erector) is not also the Supplier and prefabricator of the tank, the Supplier and the Inspector shall complete the following certificate.

 

Tank Supplier’s Certificate (for shop prefabrication is separate from erector)

 

LP Storage Tank Tag Number  ________________________

 

Project                                          ________________________

 

WE CERTIFY that, design, materials, prefabrication, and workmanship of this low-pressure tank conforms to the requirements of:

API 620 (state editions and Addendum), Design and constructions of Large, Welded, Low-pressure Storage Tanks

4WEQ-1516 (state revision) Field-Erected, Flat-Bottom, LOX and LIN Storage Tanks including Appendix Q and Appendix L

Project Equipment Specification (State document number and revision)

 

Date___________________ Signed _________________________ by  _________________

(Signed by the Supplier)

                                                  Suppliers name and address

 

I have inspected the tank described in the Supplier’s partial report (XXXXXXX), and state that to the best of my knowledge, the Supplier has constructed this tank in accordance with the applicable sections of API 620.

 

 

Date___________________ Signed _________________________ by  _________________

(Signed by the Inspector)

Inspection body name and address

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appendix O

Inner Tank Shell Manway MS (Welded)

 

Inner tank shell manway shall not be fitted as standard. They may only be used with Air Products prior agreement. The manway shall be fully welded; a free draining backing strip may be used for both LOX and LIN Tanks. The detail below is an acceptable arrangement.

 

Figure O1 

Acceptable Inner Tank Shell Manway Detail

Figure O Notes:

 

  1. The manway neck longitudinal weld Joint 1, shall be shop fabricated to be 100%PT and 100% X ray examined per ASME BPVC Section V.
  2. All field welds shall be GTAW
  3. Fillet welds shall be made with a minimum of 2 passes inspected by 100%PT per ASME BPV, section V
  4. After completion of hydro-pneumatic test, cut the manway neck (using a saw)
  5. Carry out final internal inspection of the tank
  6. Make edge preparation (groove) on manway neck.
  7. Tack weld backing strip into manway neck with drainage slot at the bottom
  8. Locate dished head
  9. Make closure butt weld – Joint 2
  10. Closure weld to be 100% PT and 100% X ray examined per ASME BPVC Section V. The liquid penetrant examination is required on the root pass and on the finished weld surface
  11. The final closure weld shall be vacuum box leak tested
  12. Reinforcing pad shall have a M6 tapped hole. The integrity of the manway to shell welds shall be tested by monitoring for leakage via the tell-tale hole during the tank pressure/leak test.
  13. Reinforcing pad shall be made from a single plate. The reinforcing pad outer diameter shall be twice the manway nominal diameter, The reinforcing pad thickness shall be the same as the inner tank shell at that location

 

Appendix P

Reduced Stress Design

 

This appendix is only applicable when specified in the PES.

 

The table lists the revised or additional criteria to API 620 code and specification 4WEQ-1516 to achieve a Reduced Stress Design for the inner tank and its anchor straps. The table includes some other requirements that need to be specified to ensure that interrelated API 620 requirements are not relaxed in exchange for the selective strengthening requirements.

 

The required Allowable Stress Reduction Factor W will stated in the PES.

  Tank Area Sub Area Requirement for Reduced Stress Design Note  
  Inner Tank Inner Tank Shell

 

Use a reduced allowable tensile stress of W times the API 620 (Q.3.3) allowable tensile stress value for required shell plate thickness calculation. Reduce Stress Design Requirement  
      All shell plate joints (double sided butts) shall be subject to  with full radiography (100% X-Ray) examination on both longitudinal and circumferential welds Reduce Stress Design Requirement  
      For design loadings combined with earthquake loading the use a reduced allowable tensile stress is NOT required. The API 620 (Q.3.3.6) allowable of 90% of the minimum yield strength may be applied. Clarification. No change to API 620 / AP 4WEQ-1516 stated requirement  
    Annular Ring Plate Annular ring plate thickness shall NOT be reduced as a result of the any increase in the required lower shell strake thickness for Reduced Stress Design API 620 Code minimum requirement is 6.35 mm.  
    Inner Tank Bottom Plates (floor) Inner tank bottom plates are already considered to be a lower level stress design.  It is NOT required to increase the thickness of the bottom plates beyond that required by API-620 / 4WEQ-1516. Clarification. No change to API 620 / 4WEQ-1516 existing requirements  
    Compression Ring

(Junction of shell and roof)

The required area of the compression ring, Ac (see equation 27 of API 620) is NOT required to be increased for this Reduced Stress Design. Do not increase the strength of the roof or roof to shell joint  beyond the existing 4WEQ-1516 requirements  
    Inner Shell External Pressure Case Reduced allowable stresses are NOT required for the external pressure loading case.  If shell thickness have been increased as a result of reduced stress design for internal pressure case, the increased shell thickness may be used in the external pressure loading case (4WEQ-1516 appendix D). This may allow a reduction in the stiffener spacing and/or the stiffener moment of inertia and area. Clarification. No change to API 620 / 4WEQ-1516 existing requirements for external pressure loading  

 

  Tank Area Sub Area Requirement for Reduced Stress Design Note  
  Inner Tank (continued) Inner Tank Roof External Pressure A Reduced Stress Design is NOT required for the inner tank roof subject to external pressure. Clarification, No change to API 620 / 4WEQ-1516 existing requirements for external loading  
    Inner Tank Anchor Straps Use a reduced allowable tensile stress of Wtimes the API 620 (Q.3.3) allowable tensile stress value for the anchor strap strength calculation. Reduce Stress Design Requirement  
      The allowable shear stress for the anchorage/pad/shell attachment welds shall not exceed 80% of the reduced allowable stress (80% of Wtimes the API 620 (Q.3.3) allowable tensile stress value). Reduce Stress Design Requirement  
      When a thickened section of the top shell course is used in as part of the required compression ring area, see details f and g of figure 5.6 the requirement of API 620 Q.3.7.4.2 applies. In this case the minimum anchorage shall also be designed for three times the internal design pressure (gas pressure). The allowable stress shall be reduced to Wtimes 90% of the minimum yield strength of the anchorage material. Reduce Stress Design Requirement  
           
  Outer Tank   Load combinations and allowable stresses stated in AP specification 4WEQ-1516 are acceptable. Clarification. No change to API 620 / 4WEQ-1516 existing requirements  
           
  Cellular Glass Base Insulation   Load combinations and allowable stresses stated in AP specification  4WEQ-1516 are acceptable Clarification. No change to API 620 / 4WEQ-1516 existing requirements  
           
  Testing   No additional requirements apply. No reduction in allowable stress is required for the testing of the tank. Clarification. No change to API 620 / 4WEQ-1516 existing requirements  
           
  Seismic Design   No additional loading is required to be considered.  Reduced allowable stresses or increased safety factors are NOT required for the seismic analysis Clarification. No change to API 620 / 4WEQ-1516 existing requirements  

 

 

 

 

Appendix Q

Seismic Design Requirements

 

Q1.      Unless local regulations are more onerous, the seismic design loads shall be determined according to API 620, Appendix L – “Seismic Design of API 620 Storage Tanks”. This uses the methodology of API 650 Appendix E with modifications applying for API 620 Appendix Q tanks.  Those requirements represent an accepted practice for tanks supported at grade and application to tanks supported on a framework above grade is beyond the scope of API 620 appendix L.  Air Products storage tanks are located on elevated reinforced concrete support structure.

 

Q2.      Conditional upon realistic spectral response accelerations for the tank on the elevated foundation being available this appendix gives an acceptable methodology for the seismic design of Air Products tanks.

 

Q3.      The applicable earthquake level considered shall be – Contingency Level Earthquake (CLE).

 

Q4.      For a CLE, the primary liquid container (inner tank) will survive and contain the liquid (with only minor leaks permitted) to protect the public but extensive damage may occur and the tank system may not be repairable after this event. This is assumed to be a singular event in the design life of the tank system.

 

The provisions are based on the ASCE 7 method with some modifications:

 

Ss = Short period (0.2 second) spectral response acceleration

S=  1.0 second spectral response acceleration values are to be used

Importance factor I = 1.0

Site Class “D” stiff soil.

 

Q5.      Design Accelerations

 

Q5.1    Impulsive Spectral Acceleration Ai, this has an API 620 Appendix L, L.4.4.2 modification to API 650 Equation E.4.6.1-1

 

Q5.2    Convective Spectral Acceleration Ac this has an API 620 Appendix L, L.4.4.2 modification to API 650 Equation E.4.6.1-4 and Equation E.4.6.1-5

 

Q6.      Freeboard

 

Q6.1    A minimum freeboard dS equal to the sloshing height of the liquid shall be provided

 

dS=0.42DAf       ref API 650 E.7.2 modified by API 620 L.4.4.3 (and L.4.3.9)

 

Q7.      Seismic Design

 

Q7.1    The seismic design of the tank shall be in accordance with API 650 Appendix E section E6 and E7 as modified by API 620 Appendix L section L.4.4.2 for a CLE.

 

Q7.2    The sliding resistance requirements stated in API  650 Appendix E section E.7.6 are modified by API 620 L.4.4.4 however a maximum coefficient of friction  m =  for steel on concrete shall be 0.4.

 

Q7.3    The coefficient of friction  m  used for the base insulation system used by the supplier must be justified by test (with test report submitted for Air Products approval).

 

Q7.4    The coefficient of friction at the following interfaces shall be considered

 

Q7.5    Cellular glass + inorganic powder + glass cloth / concrete

 

Q7.6    Cellular glass + inorganic powder + glass cloth / inorganic powder + glass cloth + cellular glass

 

Appendix R

Annular Space Piping Analysis and Piping Local Load Assessment

 

R1.       Annular Space Piping Analysis

 

R1.1    All piping between the inner and outer tanks shall be provided with sufficient flexibility to permit movement resulting from thermal contraction of the inner tank, outer tank and the pipe. Lines shall be considered fixed in the translational and torsional directions at both inner and outer tanks. It is permissible to consider the tank wall bending flexibility in two planes at the connection with the shell.

 

R1.2    Design cases to be considered covering normal operation, cooldown, and defrost are the following:

 

  Design Case Inner Tank

Temperature

Line

Temperature

Outer Tank

Temperature (Note 1)

  1 Warm +65°C (+149°F) Cold -196°C (-320°F) Warm +65°C (+149°F)
  2 Warm +65°C (+149°F) Cold -196°C (-320°F) Cold -20°C (-4°F)
  3 Cold -196°C (-320°F) Warm +65°C (+149°F) Warm +65°C (+149°F)
  4 Cold -196°C (-320°F) Warm +65°C (+149°F) Cold -20°C (-4°F)
  5 Cold -196°C (-320°F) Cold -196°C (-320°F) Warm +65°C (+149°F)
  6 Cold -196°C (-320°F) Cold -196°C (-320°F) Cold -20°C (-4°F)

 

Notes

1            Different maximum and minimum jacket metal design temperature may be required if specified in the PES.

2            All thermal expansion and contractions shall be calculated against a reference temperature of +20°C (+68°F).

3            The line pressure considered in the piping analysis shall include the liquid static head plus the gas design pressure, alternatively a maximum piping design pressure of 3.45 bar g may be adopted.

 

R1.3    An internationally recognized piping design tool shall be used to carry out the piping flexibility analysis and assessment to ASME B31.3, finite element analysis shall not be used.

 

R1.4    The following limitations apply to the allowable stresses applied in the analysis:

 

Line Type Basic Allowable Stress “S” to be used Maximum Allowable Stress for  Stress due to Sustained Loads, SL Maximum Allowable Stress Range SA for  Sustained + Displacement (Thermal) Stress Range SE
Liquid Line ASME BPVC Section VIII, Division 1 and Section II S SA = S   (Note 1)

(Note 2)

Vapor Line API 620 Table Q-3 S SA = 1.8S (Note 2)

 

 

 

 

 

 

 

 

 

 

 

 

Notes

  1. The use of higher allowables for stress combinations is not permitted.
  2. When calculating the Maximum Allowable Stress Range SA due to Sustained Loads + Displacement Strains (302.3.5 ASME B31.3), Sc shall taken to be equal to Sh. Enhanced cold properties shall not be considered. A stress range factor of f=1.2 shall be used.

 

 

R2.       Piping Local Load Assessment

 

R2.1    The piping loads on the inner and outer tanks shall be analyzed for each line.

 

R2.2    Unless when the analysis method guarantees that a correct and consistent combination of load and moment “signs” is considered, the most unfavorable combination of load and moment “signs” shall be considered regardless of load and moment sign produced by the attached piping.

 

R2.3    For liquid line nozzles on the inner tank, radial load is to be taken first as acting radially outwards with internal pressure applied (tank filled to maximum liquid level); then the radial load is to be considered as acting radially inwards with zero pressure (liquid at minimum level).

 

R2.4    Loading on nozzles shall be assessed using recognized, published methods within their scope of application (for example WRC107 may not be used for nozzle in cylinders as this is excluded from its scope of application). Extrapolation outside the defined scope or range of application of the method used is not permitted unless technically justified. The assessment shall include pressure stresses arising from the stress-raising effect of the opening’s geometry, and also from the pressure thrust exerted by the piping on the nozzle.

 

R2.5    In the analysis, only stresses due to differential thermal expansion shall be considered to be Secondary. All stresses due mechanical loads shall be taken to be Primary.

 

R2.6    Allowable Stresses for Local Loads

 

R2.6.1 Inner Tank Shell and Roof Nozzles

 

  Stress Category Primary Secondary
  General Local Membrane Bending Membrane + Bending
  Symbol Pm PL Pb Q
  Allowable for Load Combination S 1.5S  
    3S

 

 

Where S = Basic code allowable tensile stress.

 

The above is a conservative interpretation of ASME VIII Div 2 section 5.2.4, but is a requirement of all Air Products storage tanks.

 

R2.7    Outer Tank Shell and Nozzles Penetrating Elevated Foundation

 

R2.7.1 At outer tank penetrations loads are applied from the internal pipes and the external pipes. Unless project specific pipe loadings are provided by Air Products, the stress from each shall be limited to one half of the normally allowed stress limit. Therefore unless project specific pipe loadings are provided by Air Products the allowable stresses in the outer tank due to local load from the annular space piping only, shall be limited to 50% of the values stated in R.2.6.1.


 

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