🏗️ Soil Moisture Content

Construction PN-EN ISO 17892-1:

Overview

STATUS (as of 02.11.2026). PN-EN ISO 17892-1:2015-02 — English version (Polish title in the PKN catalogue: “Rozpoznanie i badania geotechniczne — Badania laboratoryjne gruntów — Część 1: Oznaczanie wilgotności naturalnej”), published 27.02.2015, implements EN ISO 17892-1:2014 and ISO 17892-1:2014 [IDT]. Since 04.11.2022 it has been in force together with amendment PN-EN ISO 17892-1:2015-02/A1:2022-11 (English version; implements EN ISO 17892-1:2014/A1:2022 and ISO 17892-1:2014/Amd 1:2022), which replaced subclauses 5.2.6–5.2.8 on cooling and weighing the dried specimen. The cards have no withdrawal note — the standard is current; ISO 17892-1:2014 has been confirmed by ISO (stage 90.93).

SCOPE (clause 1). The standard specifies a laboratory method for determining the water content of soil by oven-drying, within the scope of geotechnical investigations. The water content is required as a guide to the classification of natural soils and as a control criterion in re-compacted soils, and it is measured on samples used for most field and laboratory tests; oven-drying is the definitive procedure in usual laboratory practice. The mass loss on drying to constant mass is assumed to be free water and is referred to the mass of dry solid particles. The standard fulfils the requirements for determining water content in geotechnical investigation and testing according to EN 1997-1 and EN 1997-2.

DEFINITIONS (clause 3). Water content w is the ratio of the mass of free water to the mass of dry soil; fluid content wfl — the ratio of the mass of free water including dissolved solids to the mass of dry soil.

APPARATUS (clause 4). Forced-draft drying oven maintaining a uniform temperature throughout the chamber, where the air circulation must not transport particles; thermometer or thermocouple accurate to 1 °C to check the oven temperature; balance accurate to 0.01 g or 0.1 % of the weighed mass — whichever is greater; containers of a material whose mass does not change on repeated drying (glass, porcelain and corrosion-resistant metals are suitable), one per determination, with sufficient capacity for the specimen but not much heavier than it. For soils absorbing water vapour from the air, or if the air humidity exceeds about 60 %, specimens of less than about 200 g are tested in containers with close-fitting lids. A desiccator, if used, contains a dry self-indicating desiccant such as silica gel; it is not needed with lidded containers. Calibration requirements for the apparatus are given in Annex A.

TEST SPECIMEN (5.1). Samples stored before testing are kept in airtight non-corrodible containers at about 3 °C to 30 °C, away from sunlight, heat sources and drafts; the determination is made as soon as practicable. The specimen is selected according to the purpose of the test, the soil type and the sample type — as a representative portion of thoroughly mixed soil or as separate portions of each soil type; the specimen description is recorded and the selection method reported with the results. Recommended minimum masses of moist specimen (Table 1) depend on the maximum grain size Dmax: 30 g for 0.063 mm, 100 g for 2.0 mm, 500 g for 10.0 mm, 3 000 g for 31.5 mm and 21 000 g for 63.0 mm; a smaller specimen is noted in the report. Fine soil is sliced in half (to check for layering); the specimen should not be less than 30 g.

PROCEDURE (5.2 with amendment A1). The moist specimen is placed in a clean, dry container of known mass mc (with lid, if used) and weighed — mass m1; a container without a lid is weighed immediately after the specimen is placed in it. Large specimens are dried in flat containers with a large surface area, with the lumps broken up. The lid is removed and the container with the specimen is dried in the oven at 105 °C to 110 °C to constant mass or for the minimum time: in most cases 16 h for fine soil and about 4 h for coarse soil in a forced-draft oven. Constant mass is the point at which, after drying for a further period of at least 1 h, the mass of the dry soil changes by less than 0.1 %. Soils containing gypsum or other minerals with a significant amount of chemically bound water, and soils with a significant organic content, are not dried at this temperature but at a lower one, e.g. 50 °C, to constant mass. After removal, a lidded container is closed immediately and cooled to room temperature before weighing; a container without a lid is cooled to room temperature and weighed within 1 h of removal from the oven, or cooled in a desiccator and weighed later — a hot container distorts the weighing through convection currents. The container with lid and dried specimen is weighed — mass m2.

RESULT. From the definition of water content and the masses in 5.2: w = (m1 − m2) / (m2 − mc) · 100 %.

WHAT WE DO NOT GIVE HERE. The rounding of the result and the content of the test report (clauses 6–7), subclauses 5.2.4–5.2.5 and the calibration requirements of Annex A — the available text of the 2014 standard ends at 5.2.3, and amendment A1 concerns only subclauses 5.2.6–5.2.8. We also do not give assessments of soil suitability or a division of soils into states by water content — the description has no source for them in this standard.

Method principle

The moist soil specimen is weighed in a container of known mass, dried in a forced-draft oven at 105 °C to 110 °C to constant mass (a change of less than 0.1 % of the dry soil mass after a further period of at least one hour) or for the minimum time, cooled and weighed again. The mass loss is taken as free water: w = (m1 − m2) / (m2 − mc) · 100 %, where mc is the mass of the container (with lid), m1 — container with moist specimen, m2 — container with dried specimen.

Applications

• Classification of natural soils in geotechnical investigation — water content as a guide (scope of the standard)
• Control criterion for re-compacted soils
• Determination accompanying most field and laboratory soil tests
• Geotechnical investigation according to EN 1997-1 and EN 1997-2 — the standard fulfils their requirements for water content determination
• Soils containing gypsum or with a high organic content — drying at a lower temperature, e.g. 50 °C

Key parameters

Standard

Standard number

PN-EN ISO 17892-1:2015-02 + A1:2022-11

Title (PL)

Rozpoznanie i badania geotechniczne — Badania laboratoryjne gruntów — Część 1: Oznaczanie wilgotności naturalnej

Title (EN)

Geotechnical investigation and testing — Laboratory testing of soil — Part 1: Determination of water content

Step-by-step procedure

1. Storage of the sample

   Until testing, keep the sample in an airtight non-corrodible container at about 3 °C to 30 °C, away from sunlight, heat sources and drafts; carry out the determination as soon as practicable (5.1.1–5.1.2).

2. Selection of the specimen

   Select a representative portion of thoroughly mixed soil or separate portions of each soil type; mass of moist specimen according to Table 1 (e.g. 30 g for Dmax 0.063 mm, 100 g for 2.0 mm, 3 000 g for 31.5 mm). Slice fine soil in half to check for layering; not less than 30 g. Describe the specimen (5.1.3–5.1.5).

3. Weighing the moist specimen

   Place the specimen in a clean, dry container of known mass mc (with lid, if used) and weigh — mass m1; weigh a container without a lid immediately. Spread large specimens in a flat container and break up the lumps (5.2.1).

4. Drying

   Remove the lid and dry at 105 °C to 110 °C to constant mass or for the minimum time — in most cases 16 h for fine soil, about 4 h for coarse soil in a forced-draft oven. Dry soils containing gypsum or with a high organic content at a lower temperature, e.g. 50 °C, to constant mass (5.2.2–5.2.3).

   🌡 Temperature: 105–110 °C

5. Checking constant mass

   Constant mass: after further drying for at least 1 h the mass of the dry soil changes by less than 0.1 % (5.2.2).

6. Cooling and weighing the dry specimen

   Close a lidded container immediately and cool it to room temperature before weighing; cool a container without a lid to room temperature and weigh it within 1 h of removal, or cool it in a desiccator and weigh later. Weigh the container with lid and dry specimen — mass m2 (5.2.6–5.2.8 as worded by amendment A1).

7. Calculating the water content

   w = (m1 − m2) / (m2 − mc) · 100 % — from the definition of water content (clause 3) and the masses in 5.2. Note with the result a specimen smaller than in Table 1 and any large grains excluded from it (5.1.4).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The available text of the standard contains no safety requirements — rules for working with the oven and hot containers are set by the laboratory on the basis of a risk assessment

Frequently asked questions