Protection of underslab medical gas piping

[PEDARRIN2]

NFPA 99 requires that underslab medical gases be protected with a continuous conduit.

I have an design the is requiring running the med gas piping underslab to a floor pedestal.

What do I use for a continuous conduit?

How do I make my turns up/down while still being in the continuous conduit?

 

[imok2]

Maybe readind this will help you:

http://www.pmengineer.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2732,96139,00.html

 

[PEDARRIN2]

I have read that article in the past.

My difficulty is that we are no longer allowed to use soft copper and use bends to make direction changes.

What I came up with is burying the copper pipe in a 4" outside storm water drainage pipe and connecting it on both ends with a 18" x 4" Tee. The fittings and connections would be water tight.

18" should be enough to let the installer make his brazed joints.

On the downstream side, I am installing a 4" piece of PVC pipe which will penetrate the floor into my pedestal box.

On the other end, since NFPA requires the underslab conduit to be ventialated if electrical components are included, I have placed a 3" pipe and vent tee above my reducing tee. In the branch of the 3" tee, I have installed a residential type push in floor drain which will be flush with my wall.

Sort of seems like a backward design, but nothing else seemed to make sense.

Any suggestions?