Composite Wood Evaluation and Testing

Structural Plastics

Deckboard and Guardrail Testing

Wood plastic composites (WPCs) are produced by thoroughly mixing ground wood particles and heated thermoplastic resin. The most widespread use of WPCs in North America is in outdoor deck floors, but they’re also used for handrail and guardrail systems, stairs, fences, landscaping timbers, cladding and siding, park benches, molding and trim, window and door frames, and indoor furniture, and like any other building product, they may need to have their code compliance verified.

According to the International Residential Code (IRC), Chapter 3 Building Planning, Section R317 Protection of Wood and Wood-Based Products Against Decay, Subsection R317.4 Wood/Plastic Composites, “Wood/plastic composites used in exterior deck boards, stair treads, handrails and guardrail systems shall bear a label indicating the required performance levels and demonstrating compliance with the provisions of ASTM D7032.” NTA can label your product as part of a certification program that will verify the code compliance of your product.

What NTA can do

NTA is accredited by the International Accreditation Service (IAS) under: ISO/IEC 17025 to test, ISO/IEC 17020 to inspect, and ISO/IEC 17065 to certify the code compliance of structural plastics for manufactured homes and modular factory built construction. In addition, NTA is accredited by the IAS under ISO/IEC Standard 17025 to test and under ISO/IEC 17065 to inspect and certify structural composite wood-based products for building materials.

In 2008, NTA was one of the first accredited testing laboratories that could run the ICC-ES requirements for composite deck boards, and we’re still one of few test labs that can run the tests under ASTM D7032: Standard specification for establishing performance ratings for wood-plastic composite deck boards and guardrail systems (guards or handrails) and ASTM D7031: Standard guide for evaluating mechanical and physical properties of wood-plastic composite products. Our test lab is also able to perform ICC-ES AC 174.

WPCs are evaluated through:

  • Flexural tests
  • Temperature and mositure effects
  • Ultraviolet resistance test (NTA uses a third party)
  • Freeze-thaw resistance test
  • Biodeterioration tests (including mold)
  • Fire performance test

Deck boards are additionally evaluated through:

  • Creep-recovery test
  • Detemination of unadjusted allowable load
  • Mechanical fastener holding tests
  • Slip resistance test

Guards and handrails are additionally evaluated through:

  • Concentrated load tests
  • One- and two-family dwelling requirements

For more information about our structural plastic testing services, contact us.


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