Restrained Spring Isolator

Restrained Spring Isolator


Kinetics Model FLS vibration isolators consist of free-standing, large diameter, laterally stable steel springs assembled into welded steel housing assemblies fabricated to limit vertical movement of the isolated equipment if equipment loads are reduced, or if the equipment is subjected to large vertical external forces. The housings also provide a constant free and operating height to facilitate installation. Spring elements are complete with internal noise isolation pads and have an adjusting and leveling bolt as a part of the top load plate assembly. Springs are polyester powder coated, with a 1000-hour salt spray rating per ASTM B-117. Holes are provided in all isolators for bolting to the structure and to the supported equipment. The isolator can be welded to the structure as well. To assure stability, the springs have lateral spring stiffness greater than 1.2 times the rated vertical stiffness, and are designed to provide a minimum of 50% overload capacity. FLS Springs are available with deflections to 4" (102 mm) and with load capacities to 23,200 lbs. (10,524 kg) as standard products. Custom isolators with higher deflection and greater load capabilities are available. Kinetics Model FLS spring isolators are recommended for the isolation of vibration producing equipment carrying a large fluid load which may be drained, such as boilers, cooling towers and chillers, and for the isolation of outdoor components such as cooling towers, air-cooled condensers, etc., where wind loads are minimal.


Kinetics Model FLS vertically restrained spring isolation mounts are recommended as a noise and vibration isolator for mechanical equipment located near critically quiet areas, when the equipment to be isolated has significant changes of weight during maintenance operations, and for equipment subjected to moderate external forces or wind loads.

Operating static deflections are available up to 4" (102 mm) to compensate for long span flexible floor structures and maintain a high degree of noise and vibration isolation.


Vibration isolators for equipment which is subject to load variations and large external or torquing forces shall consist of large diameter laterally stabile steel springs assembled into welded steel housing assemblies designed to limit vertical movement of the supported equipment.

Housing assemblies shall be fabricated steel members and shall consist of a top load plate complete with adjusting and leveling bolts, vertical restraints, isolation washers and a bottom plate with internal non-skid noise isolation pads. Housing shall be electrozinc plated or hot dip galvanized for corrosion resistance. Housing should be designed to provide a constant free and operating height within 1/8" (0.06 mm).

Spring elements shall have a lateral stiffness greater than 1.2 times the rated vertical stiffness and shall be designed to provide a minimum of 50% overload capacity. Non-welded spring elements shall be polyester powder coated, and shall have a 1000 hr rating when tested in accordance with ASTM B-117.

Springs shall be selected to provide static deflections shown on the Vibration Isolation Schedule or as indicated on the project documents. Springs shall be color coded or otherwise identified to indicate load capacity. Vibration isolators shall be Model FLS, as manufactured by Kinetics Noise Control, Inc.

Mechanical Systems

Vibration Isolation Seismic & Wind Noise Control