Wood preservation facilities, chromated copper arsenate: chapter B-8
8. Operational Recommendations
Table (21 and 22) contains additional recommendations that presents good operating practices specifically applicable to Chromated Copper Arsenate (CCA) wood preservation facilities. The recommendations made here must be used in conjunction with the basic design criteria listed in Part I, Chapter A - General Recommendations for All Wood Preservatives, Section 8 and their corresponding tables. All tables of general content from Chapter A, Section 8 must be taken into consideration.
8.1 Operational Standards
The registered pesticide labels are legal documents that must be followed when treating wood with wood preservatives. The labels state the required Personal Protective Equipment (PPE), the acceptable treatment solution concentrations and the target retention rates within the wood. While not a legal requirement, the Canadian Standards Association (CSA) O80 Series of Standards specifies a number of additional requirements and recommendations related to wood preservatives, including CCA. Those standards should be followed and applied in respect of applicable laws and regulations. Process controls should be installed, maintained and calibrated in accordance with CSA O80.2-08 Clause 4.1 (referenced to American Wood Protection Association (AWPA) M3). The calibration can be conducted by facility staff if they have the appropriate training.
As per the pesticide labels, a fixation process shall be used after CCA treatment to ensure the chemical reduction of soluble hexavalent chromium and substantially immobilize CCA components in the wood before removal from protected storage. The reduction of chromium is a temperature-dependent process that needs from several hours under typical fixation chamber conditions to several weeks at near freezing temperatures. Treated wood shall be held at the treating facility in protected storage until chromium reduction has been completed and hexavalent chromium is not detectable using Method 11 of AWPA A3 and the supplementary requirements to Method 11 specified in Clause 6.5.2 (4).
8.2 Facility Wide Recommendations
In order to develop a successful facility-specific worker safety and environmental protection protocol, it is important to have an operations manual that provides written instructions to employees for all aspects of chemical use.
8.3 Area specific Recommendations
Table 21 provides additional recommended operating practices for the accelerated fixation chamber and for the dripping area. Table 22 provides additional recommended operating practices for maintenance, cleanout and shutdown of CCA treatment systems. User should refer also with Part I, Chapter A - Table 21 and Table 22 since these tables should be used in conjunction.
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