Alcance
                            ISO 18400-204:2017 contains guidance on soil gas sampling using-      active sampling (adsorbents, filters, air containers), and-      passive samplingapplied at permanent or temporary monitoring wells or other installations in soils or underneath buildings (sub-slab).It provides guidance on:-      development of a sampling plan;-      construction of monitoring installations;-      transport, packaging and storage soil gas samples;-      quality assurance.ISO 18400-204:2017 also gives basic information about-      soil gas dynamics, and-  identification of soil gas sourcesrelevant to permanent or temporary boreholes in soils or underneath buildings (sub‑slab).The compounds covered by this document are:.      volatile organic compounds (VOCs);.      inorganic volatile compounds (e.g. mercury, HCN);.      permanent gases (i.e. CO2, N2, O2, CH4).ISO 18400-204:2017 does not give guidance on:-      risk evaluation and characterization;-      selection and design of protective measures;-      the verification of protective measures, although the site investigation methodologies described can be used when appropriate;-      the sampling of atmospheric or indoor gases;-      the measurement of gases from the soil entering into the atmosphere;-      monitoring and sampling for radon.