Fire Pump Foundation

Fire Pumps Foundations

NFPA 20 (2013 edition) Section 6.4.3 states that centrifugal pumps shall be securely attached to a solid foundation in such a way that proper pump shaft and driver shaft alignment is ensured.

Foundation shall be sufficiently substantial to form a permanent and rigid support for the base plate (6.4.4). A substantial foundation is important to form a permanent and rigid support for the base plate. The foundation, preferably made of reinforced concrete, needs to be designed to adequately carry the loading of the pump, driver, and other equipment (A.6.4.4)

The pump need to be anchored to the foundation with foundation bolts to form a single structural unit.

After the pump has been properly secured to the foundation and proper alignment has been verified, the pump may then be grouted to the foundation. The base plate should be completely filled with grout, and it is desirable to grout the leveling pieces, shims, or wedges in place. Foundation bolts should not be fully tightened until the grout is hardened, usually about 48 hours after pouring.

Manufacturer Recommendations and Notes:

Aurora Pumps:

The foundation should have a level surface and have sufficient mass to prevent vibration and form a permanent rigid support for the unit. The most satisfactory foundations are concrete with anchor bolts of adequate size embedded in the foundation in pipe sleeves with an inside diameter 2½ times larger than the bolt diameter. This will allow final accurate positioning of the unit

Armstrong Pumps:

Foundation should be sufficiently substantial to absorb any vibration and to form a permanent, rigid support for the base plate. Foundation bolts of suitable size should be embedded in the concrete located by a drawing or template. Place pumping unit on foundation with wedges under base plate leaving approximately 3/4” space for grouting. Carefully level the unit by adjusting the wedges until shafts of pump and driver are leveled, recreating factory alignment.  Check coupling faces as well as suction and discharge flanges of pump for horizontal or vertical position with a level.  Slight misalignment at this point may be corrected by adjusting the wedges

Xylem Pumps:

A pump should have adequate space for operation, maintenance, and inspection.  Sub Base mounted pumps are normally grouted on a concrete foundation, which has been poured on a solid footing. The foundation must be able to absorb any vibration and to form a permanent, rigid support for the pumping unit.  The foundation must be of adequate strength to support the complete weight of the pump, plus the weight of the liquid passing through it. A typical installation will have bolts with a pipe sleeve 21/2 times the bolt diameter embedded in the concrete, sized and located in accordance with the dimensions given on the Pump Certified Outline Drawing, if provided. The pipe sleeve allows movement for final positioning of the foundation bolts to conform to the holes in the Sub Base flange. 

Remove water and/or debris from anchor bolt holes/sleeves prior to grouting. If the sleeve type bolts are being used, fill the sleeves with packing or rags to prevent grout from entering. Carefully lower the Sub Base onto the foundation bolts. Hand tighten the bolt nuts. Leveling the Sub Base may be done by several methods.

When the pump is mounted directly on a structural steel frame, pumps shall be located directly over, or as near as possible to the main building members, beams, or walls. be bolted to the support to avoid distortion, prevent vibration, and retain proper alignment. If a Sub Base is being bolted to a structural steel foundation, or the Sub Base is not grouted to the concrete foundation, use shims for leveling the plate

SPP Pumps:

A foundation plinth should be constructed to support each pumpset on a floor area free from expansion joints. These foundation plinths should be sufficiently substantial to absorb vibrations and rigid enough to avoid any twisting or misalignment. As a rough guide, they should be at least 12 inches wider than the pumpset on all sides and weigh between 1 and 1.5 times the weight of the pumpset. Plinths for fire pumps are recommended to have a minimum height of 300mm but height should be sufficient to achieve the necessary weight and to accommodate the pockets for fixing bolts. Foundation height may be calculated thus:

Use a suitable concrete mixture by volume is 1:2:3 (Cement : Sand : Aggregate) with a maximum 4.00 inches slump, and a 28 day compressive strength of 1,750 tonf/in2

The foundation should be reinforced with layers of 6.00 inche square No.8 gauge steel wire fabric, or equivalent, horizontally placed 6.00 inches apart. Foundation concrete should be poured without interruption to within 1.00 inch of the finished height.

The top surface should be well scored and grooved before the concrete sets to provide a bonding surface for the grout. The foundation should be allowed to cure for several days before installation of the baseframe.

Foundation Bolts: Two types of foundation bolts are normally used; either rag bolts set into pre cast pockets in the plinth or, chemical anchor bolts for which pockets are drilled into the plinth after casting

Patterson Pumps:

The foundation should be sufficiently substantial to absorb vibration and to form a permanent rigid support for the pump. Concrete is most widely used for foundations. Before pouring a foundation, locate anchor bolts per the outline drawing. Anchor bolts should be installed in sleeves twice the anchor bolt diameter to allow for alignment with the holes in the soleplate or discharge head. Allow for 3/4 inch to 1-1/2 inches of grout between foundation and discharge head or soleplate. The top surface of the foundation should be roughened to provide a good bond for the gro

LEVELING THE UNIT:  Position the unit so the anchor bolts are aligned in the middle of the mounting holes in the base. Place metal shims or metal wedges directly under the part of the base carrying the greatest weight, and space them close enough to give uniform support and stability. Adjust the metal shims or wedges until the top flange of the discharge head is level. Tighten the foundation bolts snugly, but not too firmly, and recheck the alignment before grouting.

Conclusions.

The best way to ensure the proper foundation of the fire pump (skid mounted horizontal, end suction, turbine or in line style) is with the assistance of the structural civil engineer. Taking care all the equipment and slabs conditions.

In general, a pump should be mounted on a required baseplate supported by a reinforced concrete foundation. It is also necessary to properly connect the pump to the system by accurately aligning it to the piping system, as well as the driving motor. 

The concrete foundation must be substantial enough to absorb any vibration and form a permanent rigid support for the baseplate. A frequently used rule of thumb is that the foundation should be about two to three times the weight of the pump/motor assembly and approximately 6″ longer and wider than the skid baseplate.