Best Management Practices, or BMPs, are recommended guidelines for the production and installation of preserved wood products destined for use in aquatic and wetland environments. The guidelines were developed through a consensus process and are based on the core philosophy of chemical minimization.
Both environmental and economic concerns support the goal of placing enough preservative into a product to provide the needed level of protection while also minimizing use of the preservative above the required standard minimum. This is intended to reduce the amount potentially available for movement into the environment.
There are a variety of preservative systems and treated wood products approved for use in or above aquatic and wetland environments. All preservative systems must be approved through a registration and application process to the U.S. Environmental Protection Agency (EPA) and Canadian Pest Management Regulatory Agency (PMRA).
Minimizing Impacts
After approval has been granted, the preservative system must be classified into the appropriate Use Category System developed and maintained by the American Wood Protection Association (AWPA) or the Canadian Standards Association (CSA). These systems establish the minimum amount of chemical (retention) and depth of injection (penetration) that is needed to assure effective performance against fungal decay or other wood destroying organisms.
The additional processing requirements defined in the BMPs are separate from and in addition to the product standards. There is a shared responsibility between the specifier and treater to assure the level of chemical application selected will meet the goal of minimizing the migration or leaching of the treating chemicals into the environment.
Detailed information about BMPs can be found in the Specifiers Guide - Best Management Practices. The following is a summary of that guide.
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BMP Producers, Quality Mark
Preserved wood products that have been produced in compliance with the BMPs can be marked with the BMP mark, which is registered with Western Wood Preservers Institute.
The application or display of the BMP mark on material is authorized only to registered treating companies who have demonstrated in writing that they have a contractual relationship with an American Lumber Standard Committee (ALSC) accredited inspection agency. This agreement authorizes the agencies' oversight services for the use of the BMP mark.
The following producers are currently authorized to use the BMP mark:
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Specification Considerations
In designing a project, one needs to consider the characteristics of various preserved wood products in relation to the purpose of the project and the environmental characteristics of the site. The best available science shows that preservative-treated wood poses minimal risk to aquatic environments when:
- Used in accordance with the AWPA and CSA specifications
- Used following the guidance provided by the appropriate required documents, such as the Consumer and Safety Information Sheets or preserved wood Safety Data Sheets (SDS)
- The project risks are evaluated and the preserved wood materials are produced using the BMPs
Determining any potential impacts from using preserved wood in aquatic or sensitive environments can be done with the user-friendly Environmental Assessment Model. The online model streamlines the process of modeling the conditions for a project to estimate the potential migration of preservatives from preserved wood immersed or over water. Find out more about the model in the Aquatics section.
Preservative Selection
A key step in designing a project in an aquatic or wetland environment is the specification of the preserved wood. The purpose of treating wood products is to provide protection from wood destroying organisms or fungal decay, thus extending the useful life and structural performance of the material.
Specifiers should carefully consider the options in terms of required retention levels (AWPA or CSA Standard) as well as potential environmental impacts. The industry uses only preservative chemicals registered for the specific uses by the federal, provincial or state agencies.
The preservative chemicals used to treat wood in accordance with these BMPs shall be those listed in AWPA Use Category System (UCS) Standard U1, Section 4: Standardized Preservatives and shall comply with the requirements referenced there or as appropriately specified by the Canadian Standards Association (CSA 080). Specific solution requirements for each preservative listed in Standard U1 Section 4 can be found in the specific ‘P’ Standard referenced. Compliance with the AWPA treating solution requirements is a BMP treating criteria.
BMPs and treatment techniques are defined for the following preservatives:
- ACQ - Alkaline Copper Quaternary
- CA-B & CA-C - Copper Azole
- MCA - Micronized Copper Azole
- EL2 - DCOI/Imidacloprid/Stabilizer
- PTI - Propiconazole Tebuconazole Imidacloprid
- ACZA - Ammoniacal Copper Zinc Arsenate
- CCA - Chromated Copper Arsenate
- CuN - Copper Naphthenate
- Creosote
- Pentachlorophenol (Penta)
Specifying BMPs
There are three steps to assuring that products used in aquatic and wetland environments are produced in compliance with the BMPs:
- Specify the appropriate material in terms of preservative and performance as defined in the American Wood Protection Association (U.S.) or Canadian Standards Association (Canada) standards.
- Specify that the material must be produced and utilized in compliance with the BMPs.
- Require third-party independent inspection agency assurance that the products are produced in conformance with the BMPs.
The material preparation, treatment and post treatment procedures and technologies for achieving the BMP objectives vary among preservatives and individual treating plants. The extent of how a treating plant follows the BMPs is up to their company policy and/or an agreement with the customer. The BMPs will continue to evolve as greater understanding and new methodologies for wood treatment are developed.
Quality oversight and inspection to assure compliance with production standards is important in any manufacturing process. For BMPs, this is accomplished at two levels: Internal Quality Control at the production level and inspection with certification by an independent third-party agency. Inspection standards and protocols are shown in the Specifiers Guide - Best Management Practices.
BMP User Responsibilities
Achieving the shared goal of the BMPs cannot be accomplished unless the user of the product follows the appropriate guidelines regarding transportation, handling, inspection, storage, installation, demolition, maintenance and disposal of the product. These recommended guidelines are contained in Chapter 4 of the Specifiers Guide - Best Management Practices.
For more information, please review the full Specifiers Guide - Best Management Practices.