d-blazeD-Blaze Fire Retardant Treated wood is suitable for interior and weather protected exterior applications where fire retardant materials are specified or required by building codes. The use of Pressure-impregnated Fire Retardant Treated Wood (FRTW) is required by building codes in many major metropolitan areas for use in wall, floor and roof assemblies to help contain the spread of smoke and fire, increasing the time that people have to evacuate and move to safety.


D-Blaze is a pressure-impregnated FRTW

D-Blaze treated lumber and plywood is highly effective in controlling the spread of flame and smoke development caused by fire, and show no evidence of significant progressive combustion after 30 minutes exposed to flame.
D-Blaze FRTW meets or exceeds the testing guidelines for construction materials as established by AWPA (American Wood Protection Association) Standards.

Testing and Approvals

  • ICC-ES ESR 2645
  • Underwriters Laboratories® Classified
    UL® Class A (Class 1) with FR-s Rating / CAN/ULC AS102 & S102.2
  • National Fire Protection Association (NFPA 255)
  • City of Los Angeles Research Report: RR 24502
  • NYC Building Code (MEA Numbers 406-87 and 407-87)
  • National Building Code of Canada
  • AWPA Standardized (P50, U1, UCFR)
    Interior Type A High Temperature (HT) FRTW
  • California Department of Forestry and Fire Protection
    CSFM BML Listing for D-Blaze Plywood and Lumber
  • GREENGUARD Gold Certificate of compliance
    Product certified for chemical low emissions

Underwriters Laboratories: Each piece of D-Blaze lumber and plywood is stamped with the mark of Underwriters Laboratories, Inc. (UL) substantiating third party confirmation of flame spread and smoke developed index. Companies may only use the UL mark on or in compliance with products that have been investigated by UL and found to be in compliance with UL’s requirements. The UL Building Materials Directory has listed over a dozen species of lumber and several species of plywood for fire retardant treatment with D-Blaze.


Does D-Blaze FRTW qualify for an hourly rating in the codes?

FRTW has been awarded a UL Classification for surface burning characteristics, and by itself, does not have a resistance rating in hours. Hourly ratings are assigned to wall, roof, and deck or door assemblies. D-Blaze FRTW can be used as a component in these assemblies in structures where untreated wood is not allowed. For example; The Gypsum Association “Fire Resistance Design Manual” shows a one hour fire wall or partition assembly (WP 3605) that has wood studs covered by 5/8” Type-X gypsum board with specified nailing and positioning of panels. This assembly could be used for interior, non-bearing partitions, requiring a one hour rating in a non-combustible structure if the studs were fire retardant wood. In a similar manner, by substituting FRTW for untreated wood, other one and two hour wall and ceiling assemblies can be used in non-combustible type buildings. The model codes also permit use of ceiling assemblies with the top membrane omitted where only unused attic space is above.

What fasteners should I use with D-Blaze?

National and local building codes change frequently. Thunderbolt Wood Treating recommends that local building codes always be consulted for lists of currently approved fasteners and fastener systems. Currently, hot-dipped galvanized and stainless steel fasteners are recommended. When installed in interior applications, the fasteners shall be in accordance with the manufacture’s recommendations. Use of carbon steel fasteners may be permitted for interior applications of D-Blaze fire retardant treated wood based on Section 3.4 of ESR-2645 and Section 2304.9.5.4 of the 2009 IBC provided your company is in agreement.

Safety and Handling

D-Blaze pressure treated products do not contain any EPA listed hazardous chemicals and are easy to work with, requiring no special precautions other than routine wood working safety procedures. When working with or milling pressure D-Blaze treated wood products, the following safety precautions should be followed.

  • Wear gloves to protect against splinters
  • Wear a dust mask to reduce the inhalation of wood dusts
  • Wear appropriate eye protection
  • Wash thoroughly with mild soap and water

Safety Data Sheet
D-Blaze Facts
Information About D-Blaze
Technical Specifications
ICC-ES Evaluation Report
Plywood Listed Approval
Lumber Listed Approval