ISO 18400-204:2017 contains guidance on soil gas sampling using

- active sampling (adsorbents, filters, air containers), and

- passive sampling

applied 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 sources

relevant 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.