SPECIFICATION H

The W30 hanger is satisfactory for duct isolation since ducts vibrate at lower frequencies than piping and there is no high frequency component requiring a full LDS Rubber element. This simple spring hanger retains the 30° capability, but the housing is manufactured so that it may be attached to flat straps rather than rods. If rods are used rather than flat straps, the Type 30 serves the same purpose.

Hangers shall be manufactured with minimum characteristics as in Specification B, but without the LDS Rubber element. Springs are seated in a steel washer reinforced LDS Rubber cup that has a LDS Rubber bushing projecting through the bottom hole to prevent rod to hanger contact. Spring diameters and the lower hole sizes, shall be large enough to allow the hanger rod to swing through a 30° arc from side to side before contacting the cup bushing.

If ducts are suspended by flat strap iron, the hanger assembly shall be modified by the manufacturer with an eye on top of the box and on the bottom of the spring hanger rod to allow for bolting to the hanger straps. Submittals on either of the above hangers shall include a scale drawing of the hanger showing the 30° capability. Hangers for rods shall be Type 30 or for straps W30 as manufactured by Mason Industries, Inc.