Alkaline copper quaternary
Encyclopedia
Alkaline Copper Quaternary (also known as ACQ) is a water based wood preservative method. The treatment is made up of copper, a fungicide
, and a quaternary ammonium compound (quat), an insecticide
which also augments the fungicidal treatment is a wood preservative that has come into wide use in the USA, Europe, Japan and Australia following restrictions on CCA
. Its use is governed by national and international standards, which determine the volume of preservative uptake required for a specific timber end use.
Since it contains high levels of copper, ACQ-treated timber is five times more corrosive to common steel
, according to American Wood Preservers Association (AWPA) test results
. It is necessary to use double-galvanized or stainless steel
fastener
s in ACQ timber. Use of fasteners meeting or exceeding requirements for ASTM A 153 Class D meet the added requirements for fastener durability. The U.S. began mandating the use of non-arsenic containing wood preservatives for virtually all residential use timber in 2004.
Unless kiln dried, freshly treated ACQ lumber must be dried extensively before painting.
Modern versions have been developed which offer improved performance to those mentioned above. The American Wood Protection Association (AWPA) standards for ACQ require a retention of 0.25 pounds per cubic ft (PCF) for above ground use and .40 pcf for ground contact.
Chemical Specialties, Inc (CSI, now Viance) received U.S. Environmental Protection Agency's Presidential Green Chemistry Challenge Award in 2002 for commercial introduction of ACQ. Its widespread use has eliminated major quantities of arsenic and chromium previously contained in CCA.
Fungicide
Fungicides are chemical compounds or biological organisms used to kill or inhibit fungi or fungal spores. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality and profit. Fungicides are used both in agriculture and to fight fungal infections in animals...
, and a quaternary ammonium compound (quat), an insecticide
Insecticide
An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...
which also augments the fungicidal treatment is a wood preservative that has come into wide use in the USA, Europe, Japan and Australia following restrictions on CCA
Chromated copper arsenate
Chromated copper arsenate is a wood preservative used for timber treatment since the mid-1930s. It is a mix of chromium, copper and arsenic formulated as oxides or salts. It preserves the wood from decay fungi, wood attacking insects, including termites, and marine borers...
. Its use is governed by national and international standards, which determine the volume of preservative uptake required for a specific timber end use.
Since it contains high levels of copper, ACQ-treated timber is five times more corrosive to common steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
, according to American Wood Preservers Association (AWPA) test results
. It is necessary to use double-galvanized or stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
fastener
Fastener
A fastener is a hardware device that mechanically joins or affixes two or more objects together.Fasteners can also be used to close a container such as a bag, a box, or an envelope; or they may involve keeping together the sides of an opening of flexible material, attaching a lid to a container,...
s in ACQ timber. Use of fasteners meeting or exceeding requirements for ASTM A 153 Class D meet the added requirements for fastener durability. The U.S. began mandating the use of non-arsenic containing wood preservatives for virtually all residential use timber in 2004.
Unless kiln dried, freshly treated ACQ lumber must be dried extensively before painting.
Modern versions have been developed which offer improved performance to those mentioned above. The American Wood Protection Association (AWPA) standards for ACQ require a retention of 0.25 pounds per cubic ft (PCF) for above ground use and .40 pcf for ground contact.
Chemical Specialties, Inc (CSI, now Viance) received U.S. Environmental Protection Agency's Presidential Green Chemistry Challenge Award in 2002 for commercial introduction of ACQ. Its widespread use has eliminated major quantities of arsenic and chromium previously contained in CCA.