Asolid foundation is a proven way to increase the mean time between planned maintenance for most types of rotating equipment. Pump bases and foundations constructed of polymer concrete provide many benefits over their cast and fabricated metal counterparts. Often referred to as a poly, granite, or mineral cast baseplate, this material is a special combination of well-defined grain size aggregates bound to a thermoset epoxy or vinyl ester resin. Manufactured in a controlled environment during a transfer molding process, these materials can be cast to precision tolerances while offering the high mechanical properties suitable for most industrial applications.
The polymeric matrix of the material provides damping ratios 20-30 times greater per identical geometry than steel or cast iron materials. Rotating equipment is often associated with its stability under the influence of various disturbances and polymer bases can effectively minimize vibrations without the need to increase the mass size of the component.
Cast mounting surfaces are typically flat within 0.002 inches per feet, which reduces soft-foot and speeds alignment. Threaded insert holes are typically cast in place or located with a CNC machine to insure precise location and perpendicularity, which eliminates bolt bound conditions often occurring with inexpensive metal bases. Difficult to machine features can easily be cast in place. Thermal expansion rates of most polymer concrete formulations are considerably less than cast iron and maintain the consistent alignment of equipment in a wider range of operating conditions.
Advanced resin systems along with inert natural aggregates provide excellent protection from many fluids that would otherwise require an expensive alloy or corrode standard cast iron or steel. Polymer concrete systems eliminate the need for additional protective coatings or periodic upkeep and maintenance activities.
Polymer concrete baseplates will not twist, bend, or diaphragm like most metal designs. This eliminates the need for time-consuming field adjustment during installation. Most designs also incorporate threaded leveling inserts along with a bottom surface ready for adhesion to grouting material without modification or special preparation. Bases can either be stilt mounted or grouted in place like a conventional hollow design.
Grouting a polymer concrete baseplate requires considerably less labor and material. Grout volumes are greatly reduced resulting in less material and labor to pour. Greater skill is often required in grouting a hollow steel frame to insure all voids are eliminated as grout is intended to be in 100 percent contact with the underside surface for proper performance and vibration damping. Since the solid pre-cast polymer concrete base will maintain structural integrity without requiring grout, many potential installation errors can be easily avoided. Stilt mounting a polymer concrete assembly takes advantage of the structural stability of the mounting surface while allowing the equipment to react to the forces and moments of the piping system.
In addition, polymer concrete materials offer low levels of heat conduction, act as an excellent electrical insulator, are non-magnetic, and resist water absorption. Mechanical properties are suitable for most indoor-outdoor environments found in the process industries.
The proven reliability of polymer concrete baseplates for rotating equipment is rapidly expanding as the features above continue to add benefit for applications of most every shape and size. By combining a consistently flat, vibration damping structure that is easy to install and maintain, polymer concrete baseplates will continue to be the choice of Reliability Personnel worldwide. ◆
Scott Sapita is co-founder and managing partner of BaseTek, LLC in Middlefield, Ohio. Scott has over twenty-eight years of experience in the rotating equipment market including product design, product management and industrial sales. He carries a BS in marketing from the University of Dayton. Contact him at

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