CCA Wood Preservative

Is anyone familiar with CCA wood preservative treatment for boardwalk applications? I work for a structural engineering firm in NC. We have designed several miles of pedestrian boardwalks and bridges in three phases. The second phase is beginning construction. The contractor is disputing the use of CCA wood preservative for the guard rails and deck boards. I know the EPA is moving away from CCA in residential applications, but can find no documentation that it can't be used for pedestrian boardwalks. I've searched AWPA and AASHTO and haven't found any clear yes or no. The DOT approved our design drawings without commenting on the preservative. The preservative the contractor wants to use has not been approved by the AWPS but has been approved by the SPIB. Any help is appreciated. thanks.

Moved because this is not related to PE Exam prep.

I ran into this issue about 12 years ago on a wetland boardwalk project. This was about 1 year before the complete withdrawal of CCA wood from residential applications. Here is what we (designer and me as owner's rep) said at the time:

[SIZE=12pt]It is important to note, CCA has been voluntarily removed from the market place for residential applications but is still the accepted standard for all industrial and non-residential applications like the boardwalk. [/SIZE]

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We could find no alternative at the time that would provide the desired level of protection in the wet environment we were going to be building in. Given that 12 years have passed since this, it would behoove yiou to do some more up to date research, though!

@Dleg,

Thanks for the response. That is the same information we still find currently. We talked to a guy that has spent 50 years in the wood preservative industry and he said CCA is still the preferred method of treatment for boardwalk/wetland application.

The problem is the contractor sent out an RFI and change order. Since the project is partially DOT funded we have to get their approval. We have corresponded with several folks at the NCDOT and each one passes it on to another. No one wants to stick their neck out.