Dricon® fire retardant treated (FRT) wood is an effective and economical material for reducing the effects of fire. Building code organizations and other construction-related agencies recognize it as an alternative to materials classified as noncombustible for a range of applications.
Introduced in 1981, Dricon FRT wood is a development of Arch Wood Protection intended for weather-protected applications. Since that introduction, Dricon FRT wood has proven itself in countless structures of many different types, from neighborhood schools to a maintenance building in Antarctica.
This treated wood contains a superior fire retardant chemical that remains stable in high temperature environments and does not increase the corrosivity of metal hardware in contact with the wood.
Dricon FRT wood provides greater design latitude for Architect, engineer and contractor, and removes many barriers associated with conventional noncombustible materials such as masonry and steel. The use of Dricon FRT wood can result in greater safety, reduced insurance rates, and easing of building code limitations.
Dricon fire retardant chemical is formulated at one chemical manufacturing facility by trained chemical operators who recognize the importance of proper chemical composition. Each batch of Dricon FR chemical is inspected and tested to be sure it adheres to the specifications of Arch Wood Protection and Underwriters Laboratories. UL lists Dricon fire retardant as a recognized fire retardant chemical, indicating its suitability for use in fire retardant applications other than wood.
The chemical is purchased by a select group of quality-minded licensees who pressure treat wood to the prescribed requirements of Arch, Timber Products Inspection, and Underwriters Laboratories.
For information on fire retardant treated wood for exterior uses, visit http://www.frxwood.com/.
How it Works
An important feature of Dricon FRT wood is that it reacts automatically when exposed to fire. Dricon chemicals react with combustible gases and tars normally generated by untreated wood and converts them to carbon char and harmless carbon dioxide and water. Wood loses strength in a fire only at the rate at which its cross section is reduced. The surface char acts to insulate underlying wood and reduces the rate at which the cross sectional area is reduced. The carbon dioxide and water vapor dilute the combustible gases to help reduce flamespread.
Preservative protection comes from the borate ingredient of the fire retardant solution. It renders the wood useless as a food source for termites and fungal decay, thereby avoiding damage caused by these organisms.
|Dricon fire retardant or Dricon FRT wood complies with or has been granted the following:|
(All are subject to revision, re-examination)
Writing a Specification That Only Dricon FRT Wood Meets
Many architects have been discouraged from writing closed, proprietary specs, often for legal, ethical, or cost reasons. If, however, your design was based on the strength properties or span ratings for one product, a substitute product may be inadequate. So, if you prefer Dricon FRT wood and base your design on its strength ratings, how can a designer ensure that it is the product that is ultimately installed?
The following are distinguishing characteristics that you can include in your spec:
- EPA-registered protection against termites and fungal decay
- An NES/NER Evaluation Report
- A 40-year roof warranty that covers both materials and labor
- Full compliance with current AWPA standards P17 (treatment FR- 1), C20 & C27
- Effective performance for 25 years
- An organic chemical formulation
- The strength design factors shown below
By including several of these characteristics in your spec, you effectively eliminate alternative products without specifying Dricon FRT wood by name. And, because of the number of independent producers of Dricon® FRT wood, you can still get competitive pricing.
Dricon Lumber Strength Design Factors* Dricon FRT Wood Compared to Untreated Lumber
|Applicable at Temperatures up to:||Southern Pine||Douglas Fir||Spruce||Other Species|
|Compression Parallel to Grain, Fc||.94||.67||.91||.65||.95||.67||.91||.65|
|Horizontal Shear, Fv||.95||.69||.94||.67||.95||.69||.94||.67|
|Tension Parallel to Grain, Ft||.92||.85||.87||.80||.98||.85||.87||.80|
|Bending: Modulus of Elasticity, E||.98||.91||.98||.91||.98||.91||.98||.91|
|Extreme Fiber Stress, Fb||.89||.80||.90||.80||.98||.80||.89||.80|
|*Applies throughout North America|
Dricon Plywood Span Ratings* for APA Rated Sturd-I-Floor and APA Rated Sheathing
|APA Rating||Panel Thickness||Dricon Rating|
|24/0||3/8, 7/16, 1/2||24/0|
|*Valid for unsanded plywood in exposures of up to 170°F,
anywhere in North America.
Plywood gluelines shall be Exposure 1 and face plies shall be Group 1 species. Allowable uniformly distributed live load at maximum span for RATED STURD-I-FLOOR and RATED SHEATHING is 85 psf for floors (55 psf for STURD-I-FLOOR 48″ OC) and 30 psf for roofs plus
8.5 psf dead load in each case.
*Arch does not recommend 5/16 or 3/8 panel thicknesses for roofing applications due to springiness.
Always check applicable local codes to insure acceptability.
Design values shown above are based on unincised wood. Several species of Dricon FRT wood are commonly incised prior to treatment. In applications where strength is critical, use only unincised lumber and apply the appropriate design factors. For more information please visit the Dricon Site.