Authorization Criteria for Anaerobic Thread Locking Systems List

Revised: 6/16/2017

All Anaerobic Thread Locking Systems to be used by the State of California Department of Transportation shall be on the Caltrans Authorized Material List before incorporation into any construction project. Anaerobic Thread Locking Systems include the following components:

  1. CLEANER - to clean lubricant and oils from the threads of the stud and nut.
  2. PRIMER - to promote rapid curing of the anaerobic compound and to minimize migration of compound on threads.
  3. ANAEROBIC THREAD LOCKING ADHESIVE - to secure nut onto stud by filling the gap between nut and stud threads. Note: Anaerobic thread locking adhesive compounds will set only where no oxygen is available.

Authorization of the system requires the following:

  1. Manufacturer provides:
    1. Letter of Intent specifying the type of products and applications.
    2. Product brochure with detailed information about all components of the Anaerobic Thread locking System including: the cleaner, primer, and anaerobic thread locking adhesive.
    3. Source Information for all the materials used on each system.
    4. Evaluation reports and test results from an ISO 17025 Certified Independent Testing Laboratory for each system submitted for authorization. Testing must be conducted in accordance with ASTM D5649, “Standard Test Method for Torque Strength of Adhesives Used on Threaded Fasteners.”
      1. Anaerobic thread locking systems should be evaluated using applicable bolt/nut combinations below.
        1. 1” ASTM A449 hot-dipped galvanized threaded rod with matching ASTM A563, Grade DH nut.
        2. 1-1/2”x4” long ASTM F3125 (Grade A325) plain bolts in 2” deep tapped holes in a 2-1/2” thick steel plate, no pre-tension.
        3. 1” x 4” long ASTM F3125 (Grade A325) plain bolts with matching ASTM A194 Grade 2H nuts.
        4. 7/8” – 9 UNC x 4” long ASTM A193 Grade B8 (Type 304 SS) plain bolts with matching ASTM A194 Grade 8 (Type 304 SS) Heavy Hex nuts.
        5. 1-1/2” ASTM F3125 (Grade A325) plain bolts with matching ASTM A194, Grade 2H, plain nuts.
        6. 1-1/4” ASTM F3125 (Grade A325), Type 1, HDG bolts with matching ASTM A563, Grade DH, HDG nuts.
      2. Systems evaluated with these bolts must meet the minimum breakaway torque of 45 lb-ft.
    5. Manufacturer’s installation instructions for each specific bolt and nut combination the company is seeking authorization for.
    6. Description of Quality Control Procedures
    7. Description of Material Tracking
    8. Ship the required paperwork to the Caltrans Transportation Laboratory in Sacramento:

California Department of Transportation
Materials Engineering And Testing Services – MS #5
Structural Materials Testing Branch
5900 Folsom Boulevard
Sacramento, CA 95819-4612

  1. Caltrans will:
    1. Ensure all required documentation is received.
    2. Review the technical information.
    3. Upon evaluation of the technical information and test results, issue an acceptance letter valid for two years or a rejection letter.
    4. Update the Caltrans Authorized Material List, if applicable.
  2. Reauthorization:
    1. Manufacturers must contact the Structural Materials Testing Branch 30 days prior to their product’s listed expiration date to schedule reauthorization testing.

Caltrans contact: Structural Materials Testing Lab,