RMS-LB 2018 with 12/20 Revisions

Sealing (revised 12/20) 32 ANSI/AARST RMS-LB 2018 (with 1220 revisions) Radon Mitigation Standards for Schools and Large Buildings Informative advisory —It is recommended that sump covers are designed to allow visual access to permit observations of conditions in the sump by way of a lid window, transparent lid or similar method. 7.5.1.2 Labeling Required ( sump covers) Sump lid labels shall be provided in compliance with Section 8.4.6 a . 7.5.3 Sump pump water discharge If flexible rather than rigid water discharge piping is found, the contractor shall recommend in writing that rigid pipe for water discharge from permanent sump pumps be installed. Sump pumps or piping configurations for water discharge from the sump pump shall have a backflow prevention valve as typically provided to protect against pump failures. Should there be a need for the contractor to alter the destination of discharged sump water, the destination shall meet requirements of local authorities. 7.5.2 Surface water relief (slabs) An alternative drainage system shall be provided and installed in accordance with guidance in Section 7.8.1 when sealing a sump or other slab opening that is the only drain relief for excess water on the slab surface. 7.6 Membranes Over Exposed Soil Informative advisory —To break the connection between soil gas and indoor air, soil and other fill material in accessible crawl spaces should be covered with concrete or a soil gas retarder membrane. 7.6.1 Soil gas retarder material (membranes general) Soil gas retarders shall meet ASTM E1745 class A, B or C. Note—These specifications include permeance, tensile strength and puncture resistance. Informative advisory —Thicker sheeting or other means to protect the membrane are recommended where crawl spaces are used for storage or frequently entered for maintenance of utilities or equipment. 7.6.2 Seams (membranes general) Seams where membrane materials are joined shall be sealed in accordance with Section 7.7.1 when sub- membrane depressurization (SMD) is employed. Otherwise, seams between adjacent membrane sheets shall be overlapped not less than 12 inches (30 cm). 7.6.3 Repairs Tears or punctures in the membrane shall be sealed by one or more of the following methods: a) A tape recommended by the membrane manufacturer; or b) An additional sheet of the membrane material that covers and overlaps the tear or puncture not less than 6 inches (15 cm) on all sides and that is sealed with a caulk complying with ASTM C920 class 25 or greater or an equivalent method. 7.6.4 Label membranes or access ports Membranes or the crawl space access port shall be labeled in accordance with Section 8.4.6 b. 7.6.5 Surface water relief (membranes) Informative advisory —When observing indications that water is likely to collect on the surface of a membrane, it is best to inform the client of observations, and to include any maintenance recommendations in OM&M documentation. Recommended solutions to consider include installing drainage for surface water in the lowest location in accordance with guidance in Section 7.8.1. 7.6.6 Securing the membrane The membrane shall be durably secured to the walls or other surfaces for crawl spaces or portions of a crawl space that are expected to be regularly accessed for maintenance, storage or other purposes.