Spring and Fiberglass Isolation Hanger Model SFH
Model SFH Vibration Isolation Hangers consist of freestanding, large diameter, laterally stabile steel springs in series with a precompressed molded fiberglass insert assembled into a stamped or welded hanger bracket. 1″ and 2″ hangers also feature a patented No-Short spring cap. To assure stability, the spring element has a minimum lateral spring stiffness of 1.0 times the rated vertical stiffness. Hangers will allow support rod misalignment through a 30° arc without short-circuiting. Isolation brackets will carry a 500% overload without failure. Model SFH hangers are superior to hangers which incorporate a spring only, that can transmit noise through the all-metal construction, and hangers incorporating noise stop pads only, that can transmit low frequency vibration which a spring would isolate. Hangers are available in deflections 1.04″ to 2.20″ (26 to 56 mm) and 4.05″ to 4.75″ (104 mm to 112 mm), and in capacities from 35 to 3850 lbs. (16 to 1747 kg). Model SFH combination hangers are recommended for the isolation of vibration produced by suspended mechanical equipment, low speed suspended fans, pumps, ductwork, piping, etc.
Model SFH hangers are recommended for use near critically quiet areas for isolating any suspended source of both audible and inaudible noise and vibration. Suspended mechanical equipment such as in-line fans, cabinet fans, and piping and ductwork in close proximity to mechanical equipment are typical uses of Model SFH hangers.
High sound transmission loss ceiling systems can be effectively isolated by the use of Model SFH hangers in the ceiling suspension system. This hanger model is particularly suitable for use in isolated ceiling systems used to shield spaces from mechanical equipment rooms, flyover aircraft, and similar sound isolation involving predominantly low frequency noise.
The minimum recommendation for the placement of spring hangers is that they be installed on all piping in the equipment room and on the first 50′ (15 m) for piping that extends outside of the equipment room. For typical installations, the three spring hangers closest to the equipment should have equal deflection to the equipment isolators. The remaining spring hangers should have a minimum deflection of 1″ (25 mm). In noise sensitive areas, the pipe hangers selected should have the same deflection as that specified for the equipment isolation and all piping in the building should be isolated.
Standard Model SFH hangers are shipped fully assembled and ready for installation in threaded rod suspension systems.
Model SFH hangers are available in a wide range of load and static deflection selections and can be provided with labor saving accessories for adaption to wire or strap suspension systems, and spring may be preloaded for ease in erecting piping at a fixed elevation.
How the self-centering no short cap works:
Indexed steps in spring cap correspond to standard washer diameters for the appropriate rod diameter. The washer and rod stay centered in the cap. Featured on the 1″ and 2″ SFH Hangers only. Patent No. 5,653,426
Polyester Powder Coated Bracket and Spring Coil
Self-Centering Cap; Patent No. 5,653,426
Vibration isolators for suspended equipment with minimum static deflection requirement exceeding .4″ (10 mm), and where both high and low frequency vibration is to be isolated, shall be hangers consisting of a laterally stable steel spring in series with a precompressed molded fiberglass insert, complete with a load plate and assembled in a stamped or welded steel bracket.
The bracket shall be finished with an polyester powder coating. The manufacturer shall provide independent laboratory testing showing that the bracket with this finish has endured a minimum of 1,000 hours of exposure to salt spray fog testing per ASTM B117 without signs of corrosion.
The fiberglass insert shall be individually coated with a flexible, moisture-impervious elastomeric membrane. The insert shall be molded from glass fibers with fiber diameters not exceeding .00027″ (6.8 microns) and with a modulus of elasticity of 10.5 million PSI (738,223 kg/cm2).
Natural frequency of fiberglass vibration isolators shall be essentially constant for the operating load range of the supported equipment.
The spring element shall have a minimum lateral stiffness of 1.0 times the rated vertical stiffness.
Vibration isolators shall be color coded or otherwise identified to indicate load capacity.
The hanger bracket shall be designed to carry a 500% overload without failure and to allow support rod misalignment through a 30° arc without metal-to-metal contact or other short circuit.
The 1″ and 2″ hanger brackets shall incorporate spring caps with indexed steps which correspond to the washer diameter of appropriately sized hanger rod to keep the rod centered in the spring cap and reduce rod misalignment. The spring caps are protected under U.S. patent number 5,653,426.
Isolation hangers shall be selected by the manufacturer for each specific application to comply with deflection requirements as shown on the Vibration Isolation Schedule or as indicated on the project documents.