RMS-LB 2018 with 12/20 Revisions

ASD (revised 12/20) 19 ANSI/AARST RMS-LB 2018 (with 1220 revisions) Radon Mitigation Standards for Schools and Large Buildings Exception 1: Alternative pipe materials Alternative materials specified in codes for “Above-Ground Drainage and Vent Pipe” 8 are permitted. Alternative pipe materials that include iron, steel and copper piping shall be joined in accordance with the pipe manufacturer’s instructions and as required by code. For buildings classified as single family structures that contain not more than four attached dwelling units on a contiguous foundation, other pipe products are permitted for use where deemed acceptable by: a) Local state licensing/certifying programs that provide written acceptability for the product; or b) Local code authorities for locations that have no state licensing/certifying program. Exception 2: Downspout material on exteriors Downspout and other light-duty rigid materials of appropriate durability are permitted for duct piping use if all of the following requirements are met: a) The material shall be installed only at exterior locations at the pressure side of the ASD system; b) Duct size shall be in accordance with Section 6.3.7 ; c) Materials shall be no less than equal to the commercial durability of existing downspout materials used for such buildings where the system is being installed. Exception: Where the building is a designated heritage preservation site or operates under similar covenants, the materials used for exterior ducting are permitted to vary according to the historic preservation guidelines or other covenant requirements; d) Use of the specific material shall be acceptable to the client and, if applicable, state licensing or certifying authorities; and e) Joined connections for downspout materials and joints shall be welded to achieve a watertight seal or sealed and mechanically fastened at each joined connection using hardware fasteners that are weather-rated for outdoor use. When joined connections are sealed and mechanically fastened : 1. Sealants shall be applied to the inner junction between joined downspout materials in a manner to both establish a complete seal and protect sealants at the bonded location from degradation. Sealants shall be durable and suitable for use on gutter materials; and 2. Where pre-formed or modified flange connections are used to join sections of duct material, the upper portion of duct material at each connection shall be flanged inward and inserted downward into the lower portion of duct material to allow water and condensate to fully drain downward without collecting water and ice at joint connections. 6.2.6 Flexible couplings Flexible coupling disconnects that comply with ASTM D5926, ASTM C1173 are permitted as an alternative for joining two portions of ASD duct piping if they establish a secure watertight connection. Equivalent watertight methods are also permitted, such as threaded pipe or union disconnect. Flexible coupling disconnects or equivalent methods are permitted for situations that include: a) where piping disassembly may be required in the future for maintenance purposes, such as required at sumps and where connecting an ASD fan; b) where joining duct piping materials that are incompatible for solvent welding; c) where physical constraints inhibit the ability to join duct pipe materials by means of a solvent weld; d) where intended to minimize noise by breaking the direct transfer of fan vibration to duct piping; and 8 As point of reference for alternative piping, see the International Residential Code (IRC) Section 3002.1(1) or the International Plumbing Code (IPC) as published by the International Code Council.