C Standards) the user would specify a different Standard for
each type of product. With 36 different C Standards, there
was a significant degree of error in product specifications.
The Use Category System took all of the information from
the C Standards, and put the information for users into
Standard U1, and the information for manufacturers
(primarily wood treaters) in Standard T1.
AWPA Standard U1 is the primary standard for
specifiers, such as architects and engineers, but also for end
users and building code officials. This Standard contains the
information needed by specifiers in order to select a product
that best suits their needs. It begins by defining the various
Use Categories (UC), which are the service conditions to
which wood and wood-based products are exposed. Section
3 of Standard U1 provides a guide to the different types of
products used, and lists recommended Use Categories.
Sections 4 and 5 list preservatives and wood species found in
the Standard. Section 6 contains the actual specifications for
each type of product in the various Use Categories, with
retention values for each species/preservative combination
and any special requirements which may apply. The AWPA
Use Category System and the various Use Categories (UC)
described in AWPA Standard U1 are trademarks of the
American Wood Protection Association, and a royalty-free
license is granted to use the UC mark if, and only if, the
product meets or exceeds the requirements of AWPA
Standard U1.
Standard T1 contains the requirements for
manufacturing products in accordance with Standard U1.
Limitations for the different processes used to protect the
wood, such as temperature and pressure limitations, incising
requirements, and many other parameters are found in this
Standard.
Preservative/Protectant Standards (P Standards):
There are several types of preservatives/protectants described
inAWPA Standards. The first type is creosote-based systems,
which include creosote itself, as well as the creosote
solutions and creosote-petroleum solutions. There are also
oilborne preservatives, which are typically an active
ingredient, such as pentachlorophenol or copper naphthenate,
dissolved in a hydrocarbon solvent, which acts as a carrier to
transport the active ingredient(s) deep into the wood fiber. In
a similar manner, waterborne preservative systems consist of
an active ingredient dissolved or dispersed in an aqueous
solution, where water is the primary carrier for the active
ingredient(s). Common waterborne preservative systems
include, but are not limited to CCA, CA,ACQ, EL2 and PTI.
Hydrocarbon Solvents (HS Standards): These
Standards provide the specifications for several hydrocarbon
solvents used as carriers in organic (carbon-based)
preservative systems, such as pentachlorophenol or copper
naphthenate.
Analytical Methods (A Standards): These methods are
useful for determining conformance of products to other
AWPA Standards and specify the acceptable procedures for