Wood preservation facilities, chromated copper arsenate: chapter B, table 21

Table 21. Additional Recommended Operating Practices for Accelerated Fixation Chamber and Dripping Area

Design feature	Recommendations
Objective	Ensure that ground contamination due to preservative drippage or leaching is minimized
Treatment process	Apply an effective final vacuum after completion of the pressure cycle.
Fixation	Fixation is a temperature- and humidity-sensitive process that may take from several hours at 60 to 70°C to more than 4 or 5 months at 5°C. Accelerated fixation at elevated temperatures (e.g. 70°C) requires the presence of high humidity conditions to ensure optimum fixation results. Accelerated fixation is preferred to fixation under ambient conditions. It can be achieved by application of elevated temperatures, while maintaining high humidity conditions. Conditions promoting drying do not result in optimum fixation levels. Where interim storage is necessary, freshly treated wood should be held in a protected, contained area until moved into the accelerated fixation unit or to the protected area used for fixation under ambient conditions. The treated wood should be released from the protected fixation area only after CCA fixation has been verified by an acceptable test method (e.g. CAN/CSA O80 and AWPA-A3/11). See also Tables 14 and 15, Drip and Fixation Areas.