Estimating Paint Removal Waste

[bridgebuster]

I working on the rehabilitation of a mile long steel viaduct. About 25% of the structure will be blast cleaned to bare metal and painted.

The pay item for disposal of paint removal waste is paid in pounds, which includes the material used to remove the paint except water. What's a good estimate in pounds/SF assuming non-recycled abrasive blast cleaning? The spec for disposal doesn't make any distinction between recycled and non-recycled materials for removal. I want to be conservative an go worst case.

Thanks

 

[TomDOT]

Depends hugely on how efficient your blasting is. Crummy media, low pressure and poor blasters can easily generate 4x the waste as a quality job - or more!

I don't have any good numbers for you - we use nearly 100% recycled media.

If the viaduct is lead paint, recycled would be by far the most common way to go.

 

[bridgebuster]

Thanks Tom - I'm going with 10 psf of non-recycled. Recycled is probably the best way. The trouble is the spec which pays by the pound of paint removed + whatever material is used to remove it. To me it leads to a bigger problem in the bidding. Obviously a contractor would see in the Engineer's Estimate that I'm assuming non-recyled abrasive bcause of the high quantity; if he plans to used recycled how does he bid the item without upsetting the whole bid?

 

[TomDOT]

Sounds like a bad spec to me. It encourages wastefulness on the part of the contractor.

 

[bridgebuster]

In general their policies and procedures are usually clear. Unfortunately, their specs for paint removal and containment methods (i.e. what to use where) leave too much to the imagination.

 

[TomDOT]

Hm, containment generally would reference SSPC Guide 6.