Grouting of Equipment and Structures


1.         PURPOSE


1.1       This global engineering standard defines the philosophy, types, and application of grouting materials used for the grouting of equipment and structures.



2.         SCOPE


2.1       This standard shall be followed for the grouting of equipment and structures.





3.1       Air Products Engineering Documents


American:     4ACS-640106      Grouting of Equipment and Structural Steel

European:     4ECE-M13           Grouting of Equipment and Structures



4.         PHILOSOPHY


4.1       It is important to recognize that proper preparation, placement, and curing of grout are critical to its integrity as a uniform load-bearing base. Any nonshrink grouting must conform to the preparation specifications and installation instructions of the manufacturer.


4.2       Shims and jacking screws that are used for alignment shall be removed after the grout has cured and before the anchor bolts are tightened. Voids shall be re-grouted with the same material.


4.3       Because removal of shims and wedges after grouting can be difficult, use of jack bolts for leveling and alignment is recommended where applicable.


4.4       A grout schedule with related grouting details is typically prepared to assist in defining the scope of required grouting for the equipment installation contractor. It will define the type of grout to use in an application as well as provide some conceptual details. Specific details provided on equipment manufacturer’s drawings should be referenced on the grout schedule and provided to the equipment installation contractor. Those portions of the grout schedule and details that are specific to support the installation of machinery shall be reviewed by the machinery engineer.



5.         Types


5.1       Sand/Cement grout is a mixture of Portland cement, sand, and water that is mixed to the proportions listed in the engineering specifications.


5.2       Cement-based nonshrink grout is defined as a pre-mixed, inorganic, nonmetallic aggregate and mortar that contains shrinkage compensating agents and plasticizing agents. It can be mixed to various consistencies depending on the complexity of the base being grouted.


5.3       Epoxy-based nonshrink grout is a chemical composition of resin, hardener, and aggregate that cannot tolerate carelessness in handling and installation. Epoxy grout is only placed as a flowable material. Successful preparation and curing of epoxy-based nonshrink grout demands meticulous attention to detail. It is highly recommended that a representative of the manufacturer be in attendance and oversee any epoxy grout installation.



6.         Application


6.1       General


6.1.1   Mixing and placement of sand/cement grout might not always produce a cost-effective and predictable performance. This type of material will experience some shrinkage as it cures and might not provide a complete bearing surface to transfer loading from the supporting base to the foundation. It shall not be used when 100 percent bearing of the base is required. It may be used for grouting lightly loaded equipment and structures if this type of material is known to provide a predictable and economical system for the geographical location of the facility. This type of grout should be used as a secondary grout when required for filling skid frames.


6.1.2   Cast-in-place anchor bolts will often be provided with sleeves to facilitate some adjustment of the bolt and/or to allow for bolt stretch. Bolt sleeves shall be grouted in applications where bolt stretch is not required. Bolt sleeves for cold boxes shall always be grouted.


6.2       Items Not to be Grouted


6.2.1   All stairs, ladders, transformers, switch gear, and control and electrical panels shall not be grouted.


6.2.2   Flat-bottom storage tanks shall not be grouted unless the details shown on the tank drawings indicate grouting is required.


6.2.3   Pre-engineered metal buildings shall not be grouted. If grouting is required because of poor foundation construction, grouting shall be performed by the building erector.


6.2.4   Anchor bolt sleeves for compressor and compressor motor anchor bolt applications shall not be grouted.


6.2.5   The depressed portion of the crankcase under a reciprocating Sulzer or similarly designed compressor frame shall not be grouted. This space is kept open to help dissipate the heat generated by the machine.


6.3       Items Requiring Grout


6.3.1   Cement-based nonshrink grout shall typically be used for centrifugal compressors, gear cases, motors without sole plates, and other items as indicated in grout type and thickness table in paragraph 6.4.1. Cement-based nonshrink grout is used when uniform contact of the base plate with the foundation is important but the dynamic load qualities of epoxy-based nonshrink grout are not required. Cement-based nonshrink grout can be placed as dry packed, pumped, or poured. The accessibility to the base plate and complexity of the installation will dictate the method used. A flowable mixture shall be used when the configuration of the base makes the application of dry-pack methods ineffective. Grout must be installed with strict adherence to the manufacturer’s mixing, placing, and curing instructions to ensure an effective and durable installation.


6.3.2      For designs in accordance with American specification 4ACS-640106, cement-based nonshrink grout shall be used for shop-assembled cold boxes, structural columns, and anchor bolts. (This includes under the main beams in the base of a column box.) It has been proven to be a more reliable and cost-effective material than sand/cement-type grout for that region.


6.3.3      For designs in accordance with European specification 4ECE-M13, sand/cement grout shall be used for shop-assembled cold boxes, structural columns, and anchor bolts. (This includes under the main support beams in the base of the column box.) If the bearing pressure exceeds 5 N/mm2 (725 psi), epoxy grout shall be used.


6.3.4      Epoxy-based nonshrink grout shall be used for all reciprocating compressors, associated motors, and other items as indicated in grout type and thickness table in paragraph 6.4.1. Reciprocating compressors have bearing surfaces that experience impact and dynamic loads. Epoxy-based nonshrink grout combines toughness and resiliency to withstand impact and dynamic loads which might crack the cement-based grouts. It should also be used where bearing pressures exceed the capacity of cement-based nonshrink grout.   Any auxiliary skids within 5 m (15 ft) of a reciprocating compressor above 375 kw (500HP) shall also use epoxy grout. This is because of the high cyclic forces on the foundations that are transmitted out from the compressor. Smaller reciprocating compressors (less than 375 kw) should be looked at on an individual basis; the 5 m distance can be reduced.   The first two pipe supports from all pulsation bottles shall be grouted with epoxy.   If there is high temperature buildup above 49C (120F) in any piece of machinery (like discharge pulsation bottle supports) that is in contact with the grout, a high temperature epoxy should be used.


6.3.5      It is also critical in epoxy grout installations that the extent of the grout placed beyond the particular equipment base area being grouted be limited to a maximum overhang to grout thickness ratio of 2 to 1. For example, a grout thickness of 50 mm (2 in) should have a maximum overhang of 100 mm (4 in). If the extent of the grout pour is too far beyond the equipment base, where the material is loaded in compression, the grout edges will have a tendency to curl up as it cures and can damage the foundation.


6.3.6      The thickness of the grout may also need to be increased when the length/distance that the grout needs to flow from the pour point is greater than 1.8 m (6 ft). The grout manufacturer should provide specific recommendations for their product to ensure a proper installation.


6.3.7      Epoxy-based nonshrink grout shall be used for the insulation containment structure erected around free-standing distillation columns (that is, cold can or field-erected box). The grout provides a more reliable seal between the base and the foundation, thus preventing leakage of purge gas.



6.4       Grout Type and Thicknesses


6.4.1   The following table summarizes the recommended minimum grout material thickness to be used for many common applications:














When Required

    Compressors 50 mm (2.0 in)
    Skid Frames and Castings Full Depth 40 mm (1.5 in)
    In-line Snubbers 40 mm (1.5 in)
    Pumps 40 mm (1.5 in)
    Motors (Drives) 50 mm (2.0 in)
    Auxiliary Skids within 5 m (15 ft) 40 mm (1.5 in)
    First Two Pipe Supports after Pulsation Bottles 40 mm (1.5 in)
    Centrifugal Compressor (2) 25 mm (1.0 in)
    Centrifugal Pumps (2) 25 mm (1.0 in)
    Skid Frames and Castings (2) Full Depth 25 mm (1.0 in)
    ID and FD Fans 40 mm (1.5 in)
    Steam Turbines 50 mm (2.0 in)
    Motors with Sole Plates/Rails 50 mm (2.0 in)
    Motors without Sole Plates/Rails (2) 25 mm (1.0 in)
    Heat Exchangers 25 mm (1.0 in)
    Truck Scales 25 mm (1.0 in)
    Lube Oil Consoles 25 mm (1.0 in)
    Shop-Assembled Cold Boxes 40 mm (1.5 in)
    Field-Erected Cold Boxes 40 mm (1.5 in)
    Insulation Containment Can 40 mm (1.5 in)
    Building Columns (if required) 25 mm (1.0 in)
    Pipe Rack Column 25 mm (1.0 in)
    Miscellaneous Equipment Supports 25 mm (1.0 in)
    Miscellaneous Pipe Supports 25 mm (1.0 in)
    Skid Frames Full Depth 25 mm (1.0 in)



(1)  Projects performed using 4ECE-M13 may substitute sand/cement grout for cement-based nonshrink grout if appropriate.

(2)  Epoxy grout may be substituted at the discretion of the machinery engineer when the complexities of the equipment base and grout details make the effective placement of cement-based nonshrink grout very difficult.



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