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

1.         PURPOSE


1.1       This worldwide engineering specification defines the requirements for internal shutoff valves for field erected, flat-bottom, LOX and LIN storage tanks.



2.         scope


2.1       This specification applies when the project equipment specification (PES) requires that liquid withdrawal line connections be fitted with internal shutoff valves. Internal shutoff valves are not required unless specifically requested.


2.2       This specification shall be used in conjunction with 4WEQ-1516.



3.         related documents


3.1       Air Products Engineering Documents


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

4WEQ-1516                  Field-Erected, Flat-Bottom, LOX and LIN Storage Tanks


3.2       National Fire Protection Association (NFPA)


70        National Electrical Code





4.1       When required by the PES, the storage tank liquid withdrawal line connections shall be fitted with internal shutoff valves.


4.2       The tank supplier shall provide a complete system including internal valves, operating cables, valve actuators, control cabinet, instrument air supply lines, electrical cabling, including mechanical protection, and junction box.


4.3       The internal shutoff valves are required on all liquid withdrawal lines. Typically, LOX tanks will have liquid withdrawal line nozzles such as G1 and G2. LIN tanks will have an additional nozzle G3. Valve operators shall be mounted on roof nozzles such as GG1 and GG2 and for LIN tanks GG3 (see Figures 1 and 2).


4.4       Maintenance platforms, with walkways to these platforms, shall be provided to service the internal shutoff valve actuators.


4.5       Each actuator shall operate pneumatically, be equipped with a position indicator, and fail the valve in the closed position. An additional cable and operating mechanism shall be provided to enable the valve to be opened manually. This system shall be provided with means of lifting the valve open and must be easy for one man to operate quickly; the manual force required to open the valve shall not exceed 350 Newtons (79 pounds).


4.6       The actuator shall be leaktight in the open or closed position.


4.7       Assembly/installation/operating/testing instructions are required.


4.8       A price for spares shall be included in the tank supplier’s bid.


4.9       All materials in the actuator shall be oxygen compatible.


4.10    Cables must be removable for actuator replacement while the tank is in service, but depressurized.


4.11    Internal shutoff valves shall be 6 inch diameter, be one of the following models, and be cleaned to satisfy the requirements of 4WPI-SW70003.


4.11.1 For liquid withdrawal lines that exit the through the inner tank bottom:


  • Anderson, Greenwood and Company,1 Part Number 04-6250-511 (1987 modified version:  Gravity Close), furnished with stainless steel disc, Inconel2 alloy springs, and Teflon3 seat. Orifice plate material shall be of the same material as the inner tank


  • Protego4 NB/AP 150.


4.11.2 For liquid withdrawal lines that exit the through the inner tank side wall:


  • BOC5 flap valve model 7776002.


  • BSL7


4.12    Valve actuators shall be shall be one of the following:


  • Anderson, Greenwood and Company,1 Part Number 04-6225-531, pneumatic type, with manual open for emergencies. Operators shall be furnished with stainless steel components and Viton6 fluoroelastomer seals, and 1/8 inch diameter stainless steel cables. Operator housings shall be equipped with a position indicator and weather-shield assembly, Part Number 04-6249-001.


  • Protego4 NB/AP 150.


  • BSL7


4.13    The tank supplier shall provide a 1 1/2 inch NPS instrument air line (AA) for each pair of actuators. The electrical cabling for the solenoid valve and actuator position indicator may be run from the bottom of the outer tank in a 3/4 inch electrical conduit (EE) or, if armored cables are to be used, these may be fixed to the instrument air line(s). The instrument air line(s) shall terminate with a check valve(s) at the bottom of the outer tank and the electrical cabling shall terminate at a junction box near the bottom of the outer tank (see Figure 3). Air Products will supply a single 24 Vdc power cable to the junction box.


4.14    The air supply pressure will be specified in the PES. The tank supplier shall provide a regulator, if required.

Figure 1


Tank Schematic








Note:  Additional nozzles G3 and GG3 for LIN tanks only.






Figure 2                                                                    


Nozzles GG1 and GG2 (and GG3 for LIN Tanks only)














Note:  Supplier shall size the nozzle to ensure that cables cannot rub the nozzle bore in the cold condition.


Figure 3


Instrument Schematic of Inner Tank Valves







Notes to Figures 3


  1. The layout shown is for one valve actuator. Tanks will have two or more valve actuators.


  1. Inner tank valve instrument shall consist of the components listed below and be arranged as shown on the figures.


Internal shutoff valve (see paragraph 4.11)

Valve Actuator (see paragraph 4.12)

Globe valve, 3-way, bronze, 3/8 inch

Solenoid valve, 3-way, single, 3/8 inch, Asco8 Type EF8320G184, 24Vdc

Control panel:


Control panel enclosure shall be weatherproof to IP65 or Type 4, in accordance with


Weatherproof enclosure shall be attached to the handrail of the platform and shall be located close to the inner tank valve actuators; the length of air line between the solenoid valve and the actuator shall be kept to a minimum. The tank supplier may choose to have a separate control panel for each actuator or have a shared control panel for each pair of valve actuators.


Check valve, 1 1/2 inch, brass, Circle Seal9 249B-4PP or equivalent

Junction box with terminal strip, manufacturer’s standard, or equivalent. Components consist of an IP65 or NEMA 4 watertight junction box with barrier terminal assembly Hoffman10 Catalog Number A-1008NF JIC box; including Catalog Number A-8JTMA bracket assembly; Catalog Number A-10JBNS 12 block terminal strip; and Myers11 Catalog Number ST-2 gasketed conduit hubs (2), or approved equivalent (one per tank).


  1. The supplier shall provide supports for all piping and electrical cabling. The cable shall have suitable mechanical protection. The mechanical protection may be armored cables or electrical conduit. Armored cables may be run fixed to the air lines by using tie wraps. Electrical conduit shall be rigid galvanized steel and shall be installed by using electrical conduit fittings equal to Crouse Hinds12Form 8 fittings. Conduit shall be installed and supported in accordance with
    NFPA 70, Article 346.


  1. All instrument air line(s) shall be galvanized carbon steel with threaded connections.


  1. Instrument air lines shall be pressure tested and soap bubble checked.


  1. Each instrument air line may be used to supply two actuator valves.






Table 1


Material Manufacturer Listing


(USA suppliers unless stated otherwise)




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


  1. Inconel – Huntington Alloys, Inco Alloys International, Inc., Huntington, WV 25720


  1. Teflon – E. I. Du Pont de Nemours & Co., Inc., 1000-T Market St., Wilmington, DE 19898


  1. Braunscherweigher Flammenfilter (Protego) – Industriestr. 11, 38110 Branunschweig, Germany


  1. British Oxygen Company (BOC) – Deer Park Road, London SW19 UK.


  1. Viton – E. I. Du Pont de Nemours & Co., Inc., 1000-T Market St., Wilmington, DE 19898


  1. BSL Industries – 108 Route de Reims 02207, Soissons, Cedex, France


  1. Asco Sintering Co., 2760-T Garfield Avenue, Commerce, CA 90040


  1. Circle Seal Controls, Brunswick Corp., P.O. Box 3666-T, Anaheim, CA 92803


  1. Hoffman Engineering Co., 900-T Ehlev Drive, Anoka, MN 55303


  1. Myers Electric Products, Inc., P.O. Box 22086, Los Angeles, CA 90022


  1. Crouse-Hinds Co., P.O. Box 4999, Syracuse, NY 13221




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