Until 1982, neither the equipment for executing cone penetration tests nor the tests themselves were standardised. In that year, a first standard for carrying out cone penetration tests was published in the Netherlands:
NEN3680: Subsurface studies - Static cone penetration testing methods (1982, first edition).
In 1996, this standard was amended and published as:
NEN5140: Geo-engineering - Establishing the cone resistance and the local cohesive strength of sediment - Electrical cone penetration testing method (1996, first edition).
In 2009, this second NEN standard was replaced by;
ISO 22476-12:2009: Geotechnical investigation and testing – Field testing – Part 12: Mechanical cone penetration test (CPTM)
The cone penetration tests in the database do not have a quality label or code, but this will certainly change in the future. In the meantime, the metadata of a cone penetration test, such as date of test, standard, number of measurements and data types, provide a first impression of the quality of the cone penetration.
More information about NEN3680 and NEN5140 is available at www.nen.nl. An NEN subscription is required if you wish to download the NEN standards. The ISO standard can be downloaded from www.iso.org/iso/home/standards.