How to prevent soil contamination at slab / pavement interface? 1

[jms336]

We are preparing a site plan for an auto body facility that will have a paint booth inside. At the roll-up doors nearest the paint booth, there is a concern (from the City Engineer) about contaminants seeping into the soil where the building slab meets the site pavement. The City Engineer is suggested a liner be placed below the pavement at this location to contain any contaminants that are spilled in this area.

This seems a bit backwards to me, in that there is no way to recover the contaminants from this location short of demolishing the pavement. I would think it better to ensure a tight joint that will exclude any contaminants in the first place from getting under the pavement. Any thoughts or experience with this type of thing is appreciated.

 

[dgillette]

Consider a concrete apron extending a little way outside the door, with water stops at the construction joint between inside slab and outside apron. Watch out for differential settlement, however, as that could tear the water stop apart. The ones I'm familiar with are shaped like this in cross section: ---O--- One side goes in each slab. The O in the middle is a tube that gives it more stretch than if it was one flat piece.

One thing I don't know about is the chemistry - is there a problem with paint solvents on the polymer in the waterstops? In days of old, waterstops were made of copper, which would not have that problem with organic solvents, but would likely be more prone to tearing.

 

[cvg]

copper waterstops can still be used. If there is significant concern about recovering spilled chemicals, a gutter leading to a catch basin could be constructed at the edge of the building. Or better yet, berm containment as you see at gas stations and refineries.

You are correct that any small amount of contaminants that get down into the joint cannot be easily recovered. However, this requirement (by the city) seems like a bit of overkill to me. I don't think it will be a significant problem as there shouldn't be a lot of spills in the vicinity of the roll up doors and recovery of those spills would not likely be done anyway.

 

[Unotec]

I agree with cvg, it sounds pretty exagerated the concern. However, there are sometimes that you have to concede with these type of situations.
If you have to put a liner and cannot get away with a small bump/berm, you can put the liner underneath the concrete with a slight slope into a small monitor well, which can be as simple as a 1-2" pipe. This can be sucked every time it fills.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[dicksewerrat]

Why not place a shallow trough inside the bldg and run the contaminants to a flammable waste trap. They should have one in the bldg plan already.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[jms336]

Thanks for all the suggestions. We have proposed a concrete slab with waterstop at the doorways. I think the City Engineer will accept this. I can post more if he does accept it.