February 14, 2001 The Executive Committee of the American Wood Protection Association gave final approval on January 26 for listing of ACZA-treated railroad ties in the AWPA Book of Standards. Ammoniacal Copper Zinc Arsenate (ACZA) has been listed in AWPA standards since 1983 as an accepted wood preservative, but it was not listed for protection of ties. Recent pressures on creosote-treated ties led Arch Wood Protection, Inc., licensor of the Chemonite brand of ACZA-treated wood, to submit test data to AWPA membership for tie applications.
The data package was
submitted to an AWPA technical committee, and its positive reaction was sent to
the general membership which voted in favor of the listing. AWPA is a consensus
organization that establishes standards for the wood preserving industry. Its
membership consists of preservative manufacturers, treaters, users of treated
wood, scientists, academics, and other interested parties.
The Chemonite® treating
process can meet requirements for penetration of difficult-to-treat species
such as Douglas fir, according to Grady Brafford, senior sales manager at Arch
Wood Protection. Brafford explained that, "Douglas fir is a strong, plentiful
species – well-suited for use as ties – but not readily treated with other
preservatives. Chemonite® ties combine the strength of Douglas fir with
effective preservative properties."
Tests of ACZA-treated
ties have shown low corrosivity and excellent spike-holding characteristics.
The preservative enables wood to resist termite damage and fungal decay, and
has been found to reduce flame spread in wood timbers the company notes.