Quality Control – What is Laboratory Accreditation?


Specifications in concrete quality control often state that tests must be carried out by “an approved laboratory”. The question arises approved by whom, and against which standards?

“Approval” has often been based on previous experience with a testing facility and formal auditing of the facility was seldom carried out. In the 1980’s, the South African Bureau of Standards (SABS) adopted the Code of Practice SABS 0259 which covered the competence of laboratories.

In 1990, that code was replaced by ISO/IEC* Guide 25, which in turn was superseded by SABS ISO/IEC 17025 in 1999. This standard code of practice is still current and is entitled “General requirements for the competence of testing and calibration laboratories”.

Accreditation to this standard is the responsibility of the South African National Accreditation System (SANAS).

How Does a Laboratory Become Accredited?

The first step is to make an application to SANAS. The application must include a policy statement, procedures, work instructions, test methods, work sheets, sample reports etc.

Most importantly, the applicant must be able to demonstrate that the laboratory’s operations substantially comply with the standard’s requirements, i.e. it has a track record of producing reliable results and its staff members are competent.

These documents are subjected to review, and if the review is successful, an initial audit is scheduled. The audit team comprises a lead auditor and at least one technical auditor. The applicant may be required to revise or amend some of his/her documentation prior to the first audit.

At the first audit the lead auditor will normally audit compliance with the management requirements of the standard (there are 14 of them), and the technical auditor(s) will assess the technical competence of the laboratory in terms of the technical requirements of the standard (there are 10 of them).

This will include checking of all equipment records, calibrations, reference tests, validations, staff competency, etc.

There are three possible outcomes of the first audit:

  • Failure – this is rare as the document audit weeds out these applicants
  • Conditional approval subject to clearing of findings (with or without a follow-up audit) – this is the most common outcome
  • Unconditional approval – this is rare unless the scope of accreditation is very narrow

The accreditation period is five years and it is SANAS’ policy to keep the same audit team for that period.

Once laboratory accreditation is granted, the laboratory is re-audited after 6 months, then 12 months later, then 18 months after that. At this stage, laboratory accreditation will last for two more years when the 5-year cycle starts again with the submission of a new application. A new audit team may be appointed at this stage.

What Are The Benefits of Laboratory Accreditation?

For The Laboratory:

There are many benefits for the laboratory:

  • The management and technical competence of the laboratory is shown to be of the highest international standard
    • Certification of a laboratory to ISO 9001 or ISO 9002 does not of itself demonstrate the competence of a laboratory to produce technically valid data and result.
  • It becomes easy to manage the laboratory because procedures and methods are well structured
  • It becomes easier to detect and correct non-conformances (which still may happen)
  • It commits senior management to the quality system
  • It ensures independence of the laboratory from other company influences, for example: sales, distribution, finance, etc

For The Client:

The benefits to the client include:

  • The knowledge that results are traceable to international standards
  • The knowledge that tests have been carried out by competent staff on well-maintained, regularly calibrated equipment
  • The knowledge that results are as reliable as it possible
  • In the event of a dispute the results will carry far more weight than results from a non-accredited laboratory.

It is important for the client to realise that most accredited laboratories carry out both accredited and non-accredited work. For example, a laboratory may be accredited for concrete quality control and be asked to test concrete cubes, but not flakiness index - although it may carry out that test. It must be clearly indicated on test reports whether the test results were derived from accredited tests or not.

Commonly, non-accredited test results are marked as such and results not so marked are deemed to be accredited by default. Similarly, comments, remarks and interpretive calculations are not accredited and must be marked as such.

To Find Out More About Accreditation

To find out more about laboratory accreditation and SANAS, visit the SANAS website at www.sanas.co.za.

The site contains all of the relevant documentation and a list of accredited testing and calibration laboratories.

PPC Cement has three SANAS accredited testing laboratories at Jupiter (Johannesburg), Cape Town and Port Elizabeth. The Cape Town and Port Elizabeth laboratories carry out aggregate tests, concrete tests and cement quality control on a commercial basis.

*ISO = International Standards Organization; IEC = International Electrotechnical Commission