RMS-LB 2018 with 12/20 Revisions

ASD (revised 12/20) 28 ANSI/AARST RMS-LB 2018 (with 1220 revisions) Radon Mitigation Standards for Schools and Large Buildings 6.4.14 Protection from the elements 6.4.14.1 Informative advisory —Installation of an ASD system should include efforts to: a) Provide support directly below fan locations and the discharge location that is adequate to ensure structural integrity of the pipe configuration. For example, a physical support should be provided within 3 feet (91 cm) of the point of exhaust or within 18 inches (46 cm) above and below fans located in attics when pipe configurations might otherwise allow lateral or vertical movement of duct piping; b) Locate or configure the exhaust assembly in a manner that avoids blockage or damage to the exhaust piping as a result of snow, ice curl or other forces; and c) Secure and meet code requirements for any piping that extends high enough to require tethering or other means of lateral stability. 6.4.14.2 Icing— Informative advisory The configuration for exhaust airflow should be designed and installed to minimize significant airflow blockages from ice. 6.4.14.3 Rain and Debris— Informative advisory In locations that experience blockage from debris or pervasive torrential rain or high winds each season, rain caps may sometimes be warranted. For concerns of debris or small animals that may enter the piping, the best choice is usually wire mesh described in Section 6.4.14.4 . For torrential rain, a better choice is often a rain diverter as shown in this the diagram. 6.4.14.4 Wire Mesh or Equivalent —Informative advisory Rodent/insect screen (mesh not smaller than 1/2 in. [13 mm]) is permitted and recommended where the contractor or client is concerned that debris or small animals might enter the point of exhaust , or that fan blades might cause injury to occupants. The resulting configuration required by Section 7.3.5 would not substantially diminish whole-system air volume capacity of the ASD system. 6.5 ASD Fan Installation 6.5.1 Fan design Note —Except for this provision 6.5.1, 12/20 revision updates include all of Section 6.5. ASD fans chosen shall be designed or otherwise sealed to reduce the potential for leakage of water or soil gas. ASD fans mounted on the exterior of buildings shall be rated for outdoor use or installed in a weatherproof protective housing that results in a code compliant configuration with protection against electrical shock. ASD fans chosen shall be designed to allow rainwater or condensation from within ASD piping to pass through or around the fan when activated. ASD fans chosen shall be designed to accommodate continuous activation over a durable life span. Note 1— ASD fans should originate from a manufacturer that lists ASD ( radon mitigation ) as one of the fan’s intended uses. Note 2— ASD fans chosen should be designed to minimize objectionable noise.