ISO 18400-204:2017 土壌の質 — サンプリング — Part 204: 土壌ガスのサンプリングに関するガイダンス | ページ 6

3.1

active soil gas sampling

sampling by extracting a certain volume of soil gas

3.2

breakthrough

detection of an adsorbent control section of one or more compounds having a mass greater than 5 % of the mass quantified on the measuring section

3.3

dead volume

volume which is present between the suction opening of the soil gas probe and the sampling vial, including the volume of the sampling vial or of the adsorption tube

3.4

dense non aqueous phase liquid

DNAPL

liquid of a group of organic substances which is relatively insoluble in the water and denser than the water

3.5

direct method

direct measuring method

method of analysis where the soil gas sample (aliquot) is directly introduced into a suitable equipment without first being concentrated and subjected to analysis

3.6

direct-reading detecting tube

glass tube filled with reagents which, after drawing through certain gaseous compounds, show concentration-dependent chromophoric reactions and which are thus used for qualitative and semi-quantitative analyses as well

Note 1 to entry: It is important that attention be paid to cross‑sensitivities.

3.7

gas migration

movement of gas from the source through the ground to the adjoining strata or to emit to atmosphere

Note 1 to entry: Examples of sources include e.g. wastes within a landfill or spill of hydrocarbons.

3.8

gas monitoring well

standpipe suitably installed inside a borehole from which gas samples can be taken to measure soil gas concentrations and to monitor changes in composition of soil gas or soil gas migration (3.7)

3.9

gas sampling

collection of a volume of soil gas contained in the pore space of the soil

3.10

landfill

deposition of waste into or onto the land as a means of disposal

3.11

landfill gas

mixture of permanent gases (main components), dominated by methane and carbon dioxide, formed by the decomposition of degradable wastes within landfill sites

Note 1 to entry: It can also include a large number of VOCs (trace components).

3.12.1

lower explosive limit

LEL

lowest percentage (volume fraction) of a mixture of flammable gas with air which will propagate an explosion in a confined space at 25 °C and atmospheric pressure

3.12.2

upper explosive limit

UEL

uppermost percentage (volume fraction) of a mixture of flammable gas with air which will propagate an explosion in a confined space at 25 °C and atmospheric pressure

3.13

light non aqueous phase liquid

LNAPL

liquid of a group of organic substances which is relatively insoluble in the water and less dense than the water

3.14

method by adsorption

method in which substances to be determined are concentrated adsorptively on an adsorbent, subsequently desorbed and analysed

Note 1 to entry: The adsorbent can be e.g. activated charcoal or XAD‑4 resin.

3.15

monitoring installation

permanent or temporary device used for soil gas sampling

3.16

non aqueous phase liquid

NAPL

liquid of a group of organic substances which is relatively insoluble in the water

3.17

one‑stage soil gas sampling

sampling of soil gas directly from a soil gas probe placed in soil, without pre‑drilling

3.18

passive soil gas sampling

sampling based on the adsorption of gases of the ground on an adsorbent placed in the ground, without using artificially reduced pressure

3.19

permanent gas

element or compound that is a gas at all ambient temperatures likely to be encountered on the surface of the earth

Note 1 to entry: Permanent gas can also be defined as “element or compound that is a gas at all ambient temperatures likely to be encountered on the surface of the earth”; see ISO 11074:2015, 3.6.11.

3.20

soil gas

gas and vapour in the pore spaces of soils

3.21

soil gas monitoring device

borehole finished with suitable material for stabilisation of the borehole wall and/or for limiting the sampling area

Note 1 to entry: Depending on the type and stability of fitting, a distinction is made between temporary (for single or short‑term repeated soil sampling) and stationary and semi‑permanent or permanent soil gas monitoring points (for long-term observation).

3.22

soil gas probe

soil gas sampling probe

probe, generally a tube, which is installed directly into soil (one-stage soil gas sampling), or in a borehole (two‑stage soil gas sampling) to take soil gas samples

Note 1 to entry: By applying a negative pressure to the upper end of the soil gas probe (head), the soil gas at the lower end (tip) is drawn through the suction opening(s) and transferred to a gas collecting equipment and online measurement equipment (direct measuring method) or to an absorbent (concentration method), which are installed either in or at the head of the soil gas probe or subsequently used.

3.23

soil gas sample volume

volume of soil gas taken to form the sample

3.24

continuous soil gas sampling

sampling from a monitoring well over a controlled longer period of time (mostly several hours up to days) to observe the variations over time of the gas concentrations and of the pressure distribution in the soil

3.25

sub‑slab

soil gas sampling location just below the foundation slab of a building, within the unsaturated zone

3.26

subsoil

layer of soil beneath the surface soil and overlying the bedrock (called also “undersoil”)

3.27

two‑stage soil gas sampling

sampling done firstly through installation of a borehole with the aid of a drilling instrument or by small boring, and secondly by sampling of soil gas from a soil gas probe installed in the borehole

3.28

volatile organic compound

VOC

organic compound that is volatile under normal environmental/atmospheric conditions, although it can be found in the ground in the solid, liquid and dissolved phase form as well as in gaseous phase

Note 1 to entry: VOC can also be defined as “organic compound” which is liquid at room temperature (20 °C), which generally has a boiling point below 180 °C"; see ISO 11074:2015, 6.1.24.

Note 2 to entry: Examples include single‑ring aromatic hydrocarbons and other low boiling halogenated hydrocarbons, which are used as solvents or fuels, and some degradation products.