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(Superseded by Non-Regulatory Supplement 23 CFR Part 637)

Subject: INFORMATION: Laboratory Qualification Date: October 9, 1998
From: Chief, Highway Operations Division Refer To: HNG-23
To: Resource Center Directors
Division Administrators

The purpose of this memorandum is to serve as a reminder of some important deadlines and to provide suggestions for what constitute a qualified laboratory program. It should be noted that 23 CFR 637 does not require all laboratories to be accredited. Only State central laboratories, consultants performing Independent Assurance (IA), and consultants used in dispute resolution need to be accredited.

The regulation for Quality Assurance Procedures for Construction was published as 23 CFR 637 on June 29, 1995. The regulation established three deadlines related to laboratories. The first deadline, June 30, 1997, required each State departments of transportation (DOT's) central laboratory to become accredited. The second deadline, June 29, 2000, requires non-State DOT's laboratories which perform IA testing or testing for dispute resolution to become accredited. The third deadline, June 29, 2000, requires all contractors, vendor, and State DOT's testing used in the acceptance decision be performed by qualified laboratories.

The primary objective in establishing laboratory accreditation and qualification requirements is to ensure the capabilities of the laboratories. The ultimate objective is to assure that maximum quality control and superior highway materials are incorporated into the finished highway infrastructure element.

The following should be used as guidance in establishing laboratory qualification programs.


  • Supervisors: Supervisors of testing personnel must have a minimum of 3-years experience in testing of highway construction materials.
  • Technicians: Technicians must be qualified by a qualification program as was outlined in my July 17, 1998, memorandum on Technician Qualification.

Equipment Documentation:

  • A list or record of all laboratory equipment requiring calibration/verification is necessary to provide a qualified laboratory under 23 CFR 637.
  • State DOT's should develop test procedures and/or test manuals referencing standard testing procedures, handling, identification, conditioning, storage, retention and disposal of test samples.

Proficiency In Testing:

  • Routinely evaluate testing personnel by observations and split samples or proficiency samples which will provide the appropriate reviews for field laboratories.

Frequency of Evaluation:

  • Laboratory evaluations should be made on a 2 to 3 year cycle.
  • Data from the IA program along with observations during IA tests should be used as part of the ongoing evaluation of the laboratory.

Laboratory qualifications which contain all of the above elements will provide the assurance of meeting the objective of testing requirements for NHS projects. Any regulations questions concerning laboratory qualification should be directed to Jason Dietz, Materials Group, at 202-366-8534.

/Original Signed by/
Donald P. Steinke

Updated: 06/27/2017
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000