Acknowledgement This standard was developed through the efforts and deliberations of the consensus body for Performance Specifications for Instrumentation Systems Designed to Measure Radon Gas in Air (MS-PC), representing a cross-section of stakeholder interests and vantage points. Deep appreciation is both expressed and deserved for years of contributions in time and wisdom provided by the following consensus body members and staff: Chair: Dr Phil Jenkins (OH) Co-Chair: Melinda Ronca-Battista Stakeholder Group Delegate (Educators) Jim Burkhart (CO) RADON Measurements Lab (Educators Alternate ) Trudy Smith (MO) Spruce Environmental (Proficiency Program) Shawn Price (NC) National Radon Proficiency Program (NRPP) (Federal EPA) Jani Palmer (DC) U.S. Environmental Protection Agency (EPA) (Measurement prof.) David Wilson (TN) Technical and Science Committee (AARST-NRPP) (Mitigation prof.) Leo Moorman (CO) Professional Service Provider (Home Inspectors) Martin Smith (VA) Professional Service Provider (Scientist) Tom Voss (NM) Los Alamos National Laboratory, Voss Associates (Manufacturer) Rick Straub (OH) femto-TECH, Inc (Manufacturer Alternate ) Dave Kapturowski (MA) Spruce Environmental Assistance Team: Gary Hodgden with appreciation extended to all Assistance Team members over the years to include: Mert Oktem, BethAnne Purvis, Kelsey Wallace, Katie Breidenbach, Rhea Patel, Nanci Hemberger, Viviane Callier, Jennifer Lee, Michael Schultz and Stephany De Scisciolo Cavallo.