Small dry systems

[ContractorDave]

I recently re-piped a residential CPVC system to allow for the home-owner to move some walls. I noticed that he had a sprinkler head in the garage which is very atypical up here due to our extended very cold winters. I asked him about it and he opened a closet just inside the house entrance to the garage, and behind an access panel he showed me there was a check valve and fitting with a gauge and snifter valve. He simply put a 100psi of air into the line and Walla! he had a dry system. Now the issue of CPVC and compressed air or listings regarding dry systems aside, this is a very effective and inexpensive method of protecting a cold space.
I personally would like to see an automatic air supply with a low air trouble signal, but he said he's never had any problems with it and he takes the air off it in warmer weather for the dual purpose of keeping aware that it's there and to check for any possible leakage.
My question would be is there anything out there that's listed for this or has anyone seen this done before? It seems quite logical after the fact, but coming up through the trade has me always seeing dry systems and their valves as bulky, inefficient 2nd cousins to wet systems (not that I don't like tinkering with them).

Regards
Dave

 

[stookeyfpe]

Innovative - absolutely. Listed - probably not. Cool idea.

Can you get some pictures? I have some fellow peers heavily involved in the dwelling sprinkler provisions in the US model codes who would be intrigued with this.