🏗️ Identification and description of soils for engineering purposes by visual and manual techniques in the field and in the laboratory — division into very coarse, coarse and fine soils, primary, secondary and tertiary fractions, particle size fractions according to Table 1 (large boulders > 630 mm, boulders, cobbles, gravel, sand, silt, clay ≤ 0,002 mm), fine soils identified by plasticity, organic, carbonate and volcanic soils, loess, glacial soils, anthropogenic soils, description of bedding and discontinuities, PN-EN ISO 14688-1

Construction PN-EN ISO 14688-1

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-EN ISO 14688-1:2018-05 (Polish version), in full (our translation): “This document, which specifies the basic rules for the identification and description of soils, is intended to be used together with ISO 14688-2, which establishes the basis for classifying soils on the basis of those characteristics most commonly used in engineering practice. The characteristics may vary for particular projects or materials, so more detailed subdivisions of description and classification may be useful. This document specifies procedures for the identification and description of soils based on a flexible system for use by experienced personnel, covering the assessment of material and mass characteristics by visual and macroscopic assessment. Details of the description of individual characteristics for identifying soils and the commonly used terminology are given, including that related to the results of basic macroscopic tests carried out in the field as part of the soil identification process. This document is to be used for engineering purposes for describing soils formed by natural processes, by human activity and containing synthetic materials. NOTE 1 The identification and description of rocks are covered by ISO 14689-1. Identification and description of materials intermediate between soils and rocks are carried out using the procedures in this document, ISO 14688-2 and ISO 14689-1 as appropriate. NOTE 2 Identification and description of soils for pedological purposes, as well as within measurements for soil protection and remediation of contaminated sites, are covered by ISO 25177.” We read the text of the standard in the preview of ISO 14688-1:2017 from the cover to the end of Table 1 with its notes (page 5) and in the preview of SIST EN ISO 14688-1:2018 (European foreword); we do not have the rest of Clause 5, Clauses 6–8 or Annex A — we only know their titles from the table of contents.

ACCORDING TO THE TEXT OF ISO 14688-1:2017 (foreword, introduction, Clauses 1–5.1.1 with Table 1, table of contents). The standard was prepared by ISO/TC 182 (geotechnics); the second edition replaces ISO 14688-1:2002 after technical revision and incorporates Amd 1:2013. European foreword: EN ISO 14688-1:2018 was prepared with CEN/TC 341, conflicting national standards had to be withdrawn by August 2018, it supersedes EN ISO 14688-1:2002. Introduction: Clauses 4 and 5 give the identification rules used at all stages of ground investigation and design, Clauses 6 and 7 — the procedures for those describing soils in the field or laboratory (description of the material and of the mass characteristics: bedding and discontinuities); the level of detail depends on the soil, the size and quality of the exposure or sample and the needs of the project; the person describing should be suitably qualified and experienced; practice varies between countries; after identification ISO 14688-2 allows soils to be classified, and test results serve to check the accuracy of the description. References (2): ISO 14688-2, ISO 14689-1. Definitions (3) — among others: soil is an aggregate of minerals and/or organic materials which can be disaggregated by hand in water (also anthropogenic soil of similar behaviour: embankment fill, crushed rock, mine tailings; soil may have rock structures but lower strength); anthropogenic soil — placed by human activity, of reworked natural soils or synthetic materials; fill (with engineering control) and made ground (without); identification — naming a soil on the basis of its mineral composition, grading and/or plasticity and/or organic content (may include geological information); plasticity — propensity to undergo permanent deformation when kneaded by hand (depends on water content, mineral composition and fractions, measurable by Atterberg limits); organic soil — high proportion of plant or animal matter (very low density, usually very high water content); loess — windblown (aeolian) sediment; sulfide soil — high iron sulfide content; till — original form of glacigenic multi-graded material. General (4): soils are identified and described according to this standard, classified according to ISO 14688-2, rocks described according to ISO 14689-1; soils are natural (mineral — including carbonate, volcanic, loess and till — or organic) or anthropogenic; characteristics according to Annex A — grading of very coarse and coarse fractions, plasticity of fine fractions, organic and carbonate content; in the field the primary, secondary and tertiary fractions, carbonate and organic content and origin are determined; other constituents (salt, sulfate, gypsum) can be described; the description can later be adjusted by results of grading, plasticity and laboratory tests; steps for mineral soils: a) subdivision into very coarse, coarse and fine, b) primary, secondary and tertiary fractions, c) name, d) origin (depositional environment, geological age); mineral soils with organic secondary constituents. Identification (5.1.1): very coarse and coarse soils — by particle size fractions; fine soils — by PLASTICITY, although particle sizes are also defined for them. Table 1 (mm): large boulder lBo > 630; boulder Bo > 200 to ≤ 630; cobble Co > 63 to ≤ 200; gravel Gr > 2,0 to ≤ 63 (coarse > 20, medium > 6,3, fine > 2,0); sand Sa > 0,063 to ≤ 2,0 (coarse > 0,63, medium > 0,20, fine > 0,063); silt Si > 0,002 to ≤ 0,063 (coarse > 0,02, medium > 0,0063, fine > 0,002); clay Cl ≤ 0,002. Note 1: boundaries with one significant figure (2 mm, 6 mm) instead of two (2,0 mm, 6,3 mm) are also widespread, and the difference is of little significance in identification. Note 2: the ranges for silt and clay are given only as a reference for “silt particles” and “clay particles”, not for “silt” and “clay” as fine fractions.

STATUS (PKN catalogue cards as of 02.10.2026). The card of PN-EN ISO 14688-1:2018-05 (Polish version, published 25-11-2019, 30 pages, price group P) has no “Withdrawn” header: Building and Construction Sector, KT 254 Geotechnics, ICS 13.080.05 and 93.020, “Introduces: EN ISO 14688-1:2018 [IDT], ISO 14688-1:2017 [IDT]”, “Replaces: PN-EN ISO 14688-1:2006/A1:2014-02 – English version, PN-EN ISO 14688-1:2006/Ap1:2012 – Polish version, PN-EN ISO 14688-1:2006 – Polish version”. The PKN search for “PN-EN ISO 14688-1” (02.10.2026) also shows the English version 2018-05 and the 2005/2006 editions with amendment A1. The EVS catalogue (read 02.10.2026) lists ISO 14688-1:2017 as valid from 12.12.2017.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 02.10.2026). The number 14688-1 appears in 7 records at 6 laboratories: AB 283, AB 962, AB 1416, AB 1770, AB 1778, AB 1905. In the current scopes on the PCA website (read 02.10.2026, issues from 24.09.2024 to 22.06.2026) all give “PN-EN ISO 14688-1:2018-05”; AB 283, AB 1770 and AB 1905 also cite Part 2 (PN-EN ISO 14688-2:2018-05), and AB 283, AB 962 and AB 1416 — also the Polish standard PN-B-04481 (AB 283 and AB 1416 “p. 3”). The “Laboratories” tab searches for entries STARTING WITH “PN-EN ISO 14688-1” and shows all 6 laboratories — checked with the tab query on the production server labcoda.pl on 02.10.2026.

WHAT THE LABORATORIES TEST (PCA entries). Soils — “Macroscopic analysis” (AB 962, AB 1416, AB 1778), “Soil description, visual and macroscopic assessment method” (AB 1770, in two entries), “Soil description, visual method, macroscopic method” (AB 1905), “Determination of soil type and state, macroscopic method” (AB 283).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. Fine soils: the name silt or clay is determined by plasticity, not by particle size — the ranges of Table 1 for silt and clay refer to “particles”, not to fine fractions (Note 2), so a name given from the grading curve alone may not agree with a description according to this standard. Fraction boundaries: 2 mm and 6 mm instead of 2,0 mm and 6,3 mm is an acceptable shorthand (Note 1); three laboratories also cite the Polish standard PN-B-04481 — we have not read its text, so we do not compare its fraction boundaries with Table 1, and a description according to two documents is best given with the document named at each soil name. Purpose: the standard serves engineering purposes; description of soil for pedological purposes, soil protection and remediation is covered by ISO 25177, and classification — by Part 2. Person: the system is flexible and intended for experienced persons — the standard itself says that the description depends on the qualifications of the person describing and the quality of the sample, and that laboratory test results should verify it.

WHAT WE DO NOT STATE. We do not have 5.1.2–5.9 (composite soils, plasticity, organic content, organic, carbonate, sulfide and volcanic soils, loess, glacial and anthropogenic soils, origin), Clauses 6–8 (description of grading, particle shape and strength, composition, fines content, consistency, colour, organic and carbonate content, degree of decomposition of peat, bedding and discontinuities, reporting) or Annex A (procedures for identifying the primary fraction) — we therefore give no criteria for hand tests, no consistency scales and no descriptive terms.

Method principle

A soil is named on the basis of visual assessment and simple hand tests: it is divided into very coarse, coarse or fine, the primary, secondary and tertiary fractions are determined (fine soils — by plasticity), and then the material and mass characteristics (bedding, discontinuities) are described.

Applications

• Soils in geotechnical investigation — macroscopic analysis and soil description; 6 laboratories in PCA scopes
• Description of samples from boreholes and trial pits in the field and in the laboratory before testing
• Basis for the classification of soils according to PN-EN ISO 14688-2

Key parameters

Standard

Standard number

PN-EN ISO 14688-1:2018-05 (wersja polska; EN ISO 14688-1:2018 IDT, ISO 14688-1:2017 IDT)

Title (PL)

Rozpoznanie i badania geotechniczne — Oznaczanie i klasyfikowanie gruntów — Część 1: Oznaczanie i opis

Title (EN)

Geotechnical investigation and testing — Identification and classification of soil — Part 1: Identification and description

Step-by-step procedure

1. Subcategory

   Very coarse, coarse or fine soil (Table 1). PN-EN ISO 14688-1:2018-05 current (PKN cards as of 02.10.2026).

2. Fractions

   Primary, secondary and tertiary fraction; coarse soils by grading, fine soils by plasticity; organic and carbonate content.

3. Name and origin

   Soil name according to the procedures of the standard; origin — depositional environment and geological age, where possible.

4. Description

   Material characteristics (Clause 6) and mass characteristics — bedding and discontinuities (Clause 7); reporting (Clause 8) — outside the part we read.

5. Verification

   The description can be adjusted by results of grading, plasticity and tests of carbonate or organic content (Clause 4).

Required equipment and apparatus

Health and safety (OHS)

• The standard contains no safety warnings in the part we read
• TECHNICAL NOTE: fine soils are named by plasticity, not by particle size; for pedological purposes and remediation ISO 25177 applies

Frequently asked questions