RMS-LB 2018 with 12/20 Revisions

Sealing (revised 12/20) 34 ANSI/AARST RMS-LB 2018 (with 1220 revisions) Radon Mitigation Standards for Schools and Large Buildings 7.8.2 Utility drains to soil Openings in the slab or at sumps that serve for mechanical systemwater drainage and are likely to draw soil air into a building shall be modified to stop this airflow. The modification shall retain drainage capability, such as the use of a one-way flow valve, re-routing the drain line into a condensate pump or floor drain, or a trap in the drain that provides a minimum of 6 inches (15 cm) or greater. 7.8.3 Drains to daylight Informative advisory —A one-way flow valve or other mechanical means should be installed when a mitigation system is designed to draw soil gas from drain tiles (internal or external) that discharge water to daylight. This prevents outside air from entering the ASD systemwhile allowing an unobstructed flow of drain water to drain out of the water control system. 7.9 Sealed Isolation Assemblies Sealed isolation assemblies are not to be regarded as a permanent, stand-alone mitigation method. Note— Sealed isolation assemblies are sometimes employed to help break the connection between soil air and living spaces in order to isolate an airspace for depressurization or pressurization . A sealed isolation assembly might be the entire building shell when whole-building pressurization is applied, or an isolated airspace such as a crawl space ; false floor, wall or ceiling; or other room below or adjacent to occupied spaces. Sealing can include sealants or gaskets on hatches or doors; sealed partitionwalls, floors or ceilings; and other configurations that resist air migration across a partition or any component of the isolation assembly. Sealed isolation assemblies can sometimes prevent adverse effects on combustion appliances located in an adjoining airspace. Sealed isolation assemblies are critical for appropriate implementation of crawl space depressurization (CSD). 7.9.1 Sealing (isolation assemblies) When applying depressurization or pressurization to air within a sealed isolation assembly , any accessible openings between the isolated space and areas surrounding the isolated space shall be sealed to resist air movement between the isolated airspace and both indoor air and outdoor air. Access doors or hatches that are not to be permanently sealed shall be fitted with airtight gaskets and a means of positive closure. 7.9.2 Labeling required (isolation assemblies): Access ports into sealed isolation assemblies shall be labeled in accordance with Section 8.4.6 c.