Chromated Copper Arsenate (CCA):
Borates - An Alternative to CCA
CCA Table of Contents
Description and Formulations of Borates (Disodium Octaborate Tetrahydrate)
Borate preservatives (Disodium Octoborate Tetrahydrate or DOT) are low toxicity alternatives for protecting timber and composites from wood destroying organisms such as decay fungi and termites. They have proven effective for more than 70 years in residential and commercial construction, and their efficacy is backed by extensive field testing.
Borates are naturally occurring minerals that exist in trace amounts in rock, soil, water and all living things. Consequently, they have marginal environmental impact. Borates are also essential for plants, nutritionally important for people and key ingredients in fiberglass, glass, ceramics, detergents and fertilizers.
Borates' use as wood preservatives was first standardized by the American Wood-Preservers' Association (AWPA) in 19901. They are listed as Inorganic Boron and described by the abbreviation SBX.
Disodium Octaborate Tetrahydrate (DOT) is specially formulated for use as a water-based wood preservative - delivering the highest concentration of boron (maximum water solubility and rate of dissolution) at a near-neutral pH. DOT (Na2B8O13 · 4H2O) is registered by EPA as well as government agencies throughout Asia, North America and Europe and offers the following distinct attributes:
- Effective fungicide/insecticide against a broad spectrum of pests
- No acquired resistance among target organisms
- Essential to plant life, nutritionally important to humans2 and environmentally ubiquitous
- Inorganic salt (nonvolatile, no off-gassing)
- Odorless, colorless and non-corrosive to hardware and building materials
- Not defined as a hazardous waste nor listed by RCRA, CERCLA, SARA, Clean Water Act, Safe Drinking Water Act or Clean Air Act
Applications of Borates
DOT is listed in the AWPA Book of Standards for all Use Category 1 and Use Category 2 (UC1 and UC2) applications - where the treated wood is used above-ground and protected from weather, but may be subject to sources of moisture. Typical applications include: furnishings and interior construction, such as framing, sheathing, sill plates, furring strips, trusses, and joists.
1 The American Wood-Preservers' Association (AWPA) is the primary standard-setting body for pressure-treated wood. To become standardized by the AWPA, preservative-treated wood must undergo a series of rigorous tests to ensure its durability.
2 The Food and Nutrition Board, Institute of Medicine, Dietary Reference Intake (DRI) Report, 2000 National Academy of Sciences.