Restrained spring isolators11/24/2023 ![]() Solution: Increased Edge distance and/or thicker housekeeping pads may be required. ![]() Problem: Addition of inertia base weight must be factored into structural design for dead and seismic forces. Solution: Proper location of equipment relative to column supports can control beam deflection and therefore reduce vibration in structure. Problem: Increased floor spans tend to increase deflections. They also provide discontinuity in metal piping to reduce motor caused vibrations. They Reduce energy at blade passage frequency traveling through water column. Proper selection is required based on pump size and surrounding space considerations.įlexible connectors are required to isolate the connecting piping from the vibration source. ![]() Spring isolators are required to prevent vibration transfer. Solution: Isolate Equipment Inertia base with spring type isolators – The addition of mass to the bottom of the pump helps lower the center of gravity which reduces vibration. Solution: Flexible connectors are required to reduce equipment nozzle loads. Problem: Differential motion up to 2” in a 20’ story height. Solution: IBC 2015 requires ICC-ES approved anchors for cracked concrete and Omega Naught Factor (Horizontal forces multiplied by 2.5). Problem: Poor installation of concrete anchors. Solution: The load path must be accounted for from the center of gravity of the unit to the structure. Problem: Reinforcement and doweling in of the housekeeping pad to the structure is often overlooked. For concrete attachments, this requires ICC-ES certified anchors. Solution: All connections of the restrained spring isolators must be designed for these loads. The resulting overturning moment creates tension and shear forces that can be very large. Problem: Horizontal and vertical seismic forces are applied at the center of gravity of the unit. Solution: Certified anchorage calculations must be submitted to verify loading conditions are met for each piece of equipment. Seismic Requirements Problem: Forces are determined by a number of factors including: project location, site class, risk category, component importance factor and equipment location equipment relative to the overall height of the building. Solution: Proper selection of isolators is required with safety factor to avoid bottoming out springs or not providing adequate deflection. Uneven Weight Distribution Problem: Water and pipe weights increase force on springs under pump side of unit. Proper calculations should be performed for quantity and locations of the hangers.įlexible connectors are required to isolate the connecting piping from the vibration source. Depending on pipe size, this set-up usually requires 3 to 5 hangers on either side. Solution: Isolate Connecting Piping Spring hangers are recommended on the inlet and discharge piping before the drop and until the vibration is dissipated. Proper selection is required based on pump size and surrounding space considerations. Solution: Isolate Equipment Inertia base with spring type isolators – The addition of mass to the bottom of the pump helps lower the center of gravity which reduces vibration. Vibration can travel through the structure as well as through the connecting piping. If this vibration is transferred to the structure, it can create serious noise problems in many different areas. Non-adjustable inserts are recommended for all air conditioning applications under compressors, air handling units, centrifugal fans and most other constant frequency vibration problems.Structure-Borne Vibration Problem: Pumps are a major source of vibration. Semi-circular Neoprene sponge inserts limit movement during start and stop and prevent contact between the projections of the upper and lower semi-steel castings. These inserts are designed for a minimum of damping in all directions to allow the springs to function properly and develop installed efficiencies that are very close to the theoretical. Since the static deflection of the spring element is much greater than that provided by most rubber materials, these units will perform where it is necessary to establish low natural frequencies or to use a mounting that is more yielding than the supporting floor. Type “C” mountings are specifically designed for noise and vibration free application in critical areas on light concrete or wooden floors. TYPE “C” Spring Mountings provide a packaged solution to troublesome vibration problems.
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