manual shut off for hvac

[rjb7112]

Hey guys we have a new thing here where we need a shutoff for the fireman to shut down all the hvac at one time someone told me it was a centrip switch anyone know anything about this?

[no8no3]

Typical fan control is generaly by individual smoke detectors in the unit. Some larger plants incorporate a centriswich that kills control voltage by use of relays. This is mearly a disconnect that kills the supply voltage to a transformer, that controls these relays. It is easy to install and a lot cheaper than ADT or similar controls. The downside is someone has to be there to disengage it.

Most of the time you see this in conjunction with smoke purge fans, designed to rid the building of smoke so the fireman can better engage the fire.

[flange]

this has been commonplace in commercial for many years. it depends on lahj (local authority having jurisdiction) regulation and type of property. in larger properties it is done through relays wired from the fire/smoke control system. in smaller apps it could just be low voltage relays, or asco switches. check with your fire inspector before proceeding.

[Engineerman]

installation of a break glass near emergency exits are a good idea. You can tie it in the control panle safety loop if there aren't aux terminals.