Wet vs Dry sprinkler systems

[John Wilson]

What are the regulations permitting or excluding the use of dry sprinkler systems in an occupied & heated building?

I’ve got a multi A2 – D – E occupancy building, 3 storey approx 45,000 total sq ft that is sprinklered. I’m in the process of forcing them to install an alarm system and other upgrades. There are some significant portions of the building that are unheated and it just came to my attention that the entire sprinkler system is a dry system. I can find a couple clauses in Pt6 about protection from freezing and dry systems for cold areas but can’t find anything that says a system in a heated & occupied space must be a wet system. They might be going back to a wet system anyway for other reasons but I would still like to find the answer to this.

Can anyone direct me to something that helps me?

Thanks.

[Tyler Fournier]

Jon,

There is nothing in the Fire Code or Building Code that I can find that indicates that you cannot use a dry system in a heated area. The Building codes makes reference to automatic sprinklers systems shall be designed, constructed, installed and tested in conformance with NFPA 13 (Sentence 3.2.5.13.(1)).

NFPA 13 (see 7.2 Dry Systems) states that dry pipe systems should only be installed where heat is not adequate to prevent freezing of water. So, in my opinion, as long as you can meet the dry pipe system water delivery time based on the hazard, a dry system is adequate. It would be a recommendation for the building owner and/or tenant to convert the dry system to a wet system.

[John Wilson]

Thanks for the reply Tyler.  Where do you find the information regarding the water delivery time? This is right down my line of thinking of “wow, that’s a lot of air to bleed out of the system right into the fire zone”

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