SIST EN ISO 17892-12:2018 PDF

Overview

EN ISO 17892-12:2018 - "Geotechnical investigation and testing - Laboratory testing of soil - Part 12: Determination of liquid and plastic limits" - specifies internationally harmonized laboratory methods for determining two of the Atterberg limits: the liquid limit and the plastic limit of soils. The liquid limit is the water content at which soil changes from liquid to plastic; the plastic limit is the water content at which soil ceases to be plastic upon drying. The standard covers testing of natural soil samples or samples with particles larger than about 0.4 mm removed and defines both the fall cone method and the Casagrande method for liquid limit determination.

Key topics and requirements

• Scope and definitions: clear definitions of liquid limit, plastic limit and plasticity index (difference WL − WP).
• Two liquid-limit methods:
  • Fall cone method (note: not the same fall cone procedure as ISO 17892‑6).
  • Casagrande method.
• Specimen preparation: testing permitted on natural samples or on material finer than ~0.4 mm.
• Apparatus and calibration: requirements for balances (accuracy 0.01 g or 0.1 %), test containers, distilled/de‑ionized water, sieves per ISO 3310‑1, and specific fall cone/Casagrande equipment; Annex A covers calibration, maintenance and checks.
• Test procedure and reporting: procedures for selecting method, preparing specimens and determining limits; clauses define mandatory and optional reporting items.
• Operator judgment and variability: the standard recognises that results are influenced by operator technique and may show some variability.

Applications and users

EN ISO 17892-12:2018 is essential for anyone involved in geotechnical investigation, soil classification, and soil‑behavior assessment. Typical uses include:

• Foundation design and geotechnical engineering calculations (bearing capacity, settlement).
• Earthworks, excavation and slope stability assessments.
• Underground works and tunnelling ground characterisation.
• Laboratory quality control and comparative studies in soil mechanics research.

Primary users:

• Geotechnical engineers and consultants
• Soil testing laboratory technicians and managers
• Construction contractors and project geologists
• Regulatory bodies and standards committees

Related standards

• ISO 17892 series (other laboratory tests for soils)
• ISO 17892-1 - Determination of water content
• ISO 3310-1 - Test sieves - technical requirements
• ISO 14688-1 - Soil identification and classification

EN ISO 17892-12:2018 provides harmonized, reproducible methods for determining Atterberg limits used widely across Europe and internationally to support consistent soil characterisation and fit-for-purpose geotechnical design.