Re: Automatic fire sprinklers

[JoeRaisin <joeraisin2001@xxxxxxxxx>]

On 1/10/2011 9:03 PM, Jim wrote:
> On Jan 10, 4:38 pm, nick markowitz<nmarkow...@xxxxxxxxx>  wrote:
>>> ~~ Evan
>>
>> Unfortunately dry systems can be a pain in the ass to maintain they
>> have drum drips which must be emptied at least monthly or you risk
>> them freezing as well.
>> pcv does not sweat as much but the drums must be kept empty to prevent
>> problems
>
> Nick, can you have a dry system using PVC? I don't know much about
> sprinkler systems but I'd guess that the average water pressure in a
> home is about 80 pounds and therefore take more than that .... in air
> pressure in the pipe..... say like ..... 120 pounds ???. So will PVC
> stand up to the addional pressure necessary to maintain a dry system?
> Or am I not understanding how it works?

Usually 30 lbs or so of air is all that's needed.

To be honest, I have forgotten the mechanics of the valving but I know
the pressure 'cause I test (ITV - I haven't dumped one... yet) dry
systems all the time and the air pressure is always in the same
neighborhood.