Smoke purge

[mstrlucky74]

Can anyone help with an overview on how smoke purge wiring for a fire alarm system. I believe fa wiring is tied into modules for fans and fsd's

I think the purge system is also a manual control from the purge panel. Thanks.

 

[ron]

Depends. The term is used generically but could mean different things depending on the code section it is being applied to.

If it is truly smoke purge, such as what is used in high rise buildings in NYC, which is called post-fire smoke purge system, it is very particular per the building code section 916 and is manual activation via key switches.

http://www1.nyc.gov/assets/building..._Protection_Systems.pdf&section=conscode_2014

It can be the fire alarm system, which is a life safety system already, or it can be via the BMS with a special UL UUKL listing that allows it to do the smoke control function.

Depending on what does it tells you whether there is a relay that needs to override certain other relays during different operating modes for the FSDs and fans. Certain times they need to be shut down and other they need to be on to purge.

 

[mstrlucky74]

Depends. The term is used generically but could mean different things depending on the code section it is being applied to.

If it is truly smoke purge, such as what is used in high rise buildings in NYC, which is called post-fire smoke purge system, it is very particular per the building code section 916 and is manual activation via key switches.

http://www1.nyc.gov/assets/building..._Protection_Systems.pdf&section=conscode_2014

It can be the fire alarm system, which is a life safety system already, or it can be via the BMS with a special UL UUKL listing that allows it to do the smoke control function.

Depending on what does it tells you whether there is a relay that needs to override certain other relays during different operating modes for the FSDs and fans. Certain times they need to be shut down and other they need to be on to purge.

yes it is post smoke purge for a nyc hi rise. fsd's are part of this fire alarm wiring for the purge correct? how does the system work? thanks.

 

[ron]

yes it is post smoke purge for a nyc hi rise. fsd's are part of this fire alarm wiring for the purge correct? how does the system work? thanks.

As I mentioned, it depends. Sometimes it is part of the fire alarm.

FSDs are used irrespective of post fire smoke control and are activated during a smoke condition on the floor and duct detectors installed (NYC does both area detectors and duct detectors oddly enough although not required by code). The FACP triggers relays located at the FSDs which remove power and the FSDs spring closed not allowing air to pass. The FACP also activates relays that interrupt the start signal at the HVAC fan starters larger than 2000 cfm.

When post fire smoke purge is part of the fire alarm, the key switch panel (one key per floor) is monitored by modules that allow the FACP to trigger modules to turn on purge fans and open needed FSDs.

 

[mstrlucky74]

Ron by the way are all FSD's always tied into the fire alarm system? IF not hat dictates which are and which are not? Thanks.

 

[ron]

Almost always the FSDs are tied into the fire alarm.

The only time they are not, is when they are tied into some other type of smoke control panel (UL listed as a smoke control panel, not just a regular BMS panel that they says is doing smoke control) or a stand alone detector. A FSD must be activated by a smoke detector (or smoke sensor), so unless you are using single station type, you will also need the fire alarm system to tell the smoke control panel or FSD that there is a smoke condition.

 

[gadfly56]

Are you talking smoke purge, smoke control, or both? They are different things. The high end fire alarm control panel (FACP) manufacturers have all the components necessary to accomplish whichever combination you have. However, NYC for one and others as well like to see a separate smoke control/purge panel and that typically comes custom from a third party. The FACP manufacturers typically won't touch that panel design. One supplier I know of is Space Age Electronics. They do panel designs using components from Siemens, EST, or Notifier. Here is their page on smoke control.

As Ron pointed out, smoke control can be by the FACP or a UUKL listed BMS. You may also have either a dedicated or non-dedicated duct system and fans. Non-dedicated units function as normal HVAC systems when not in smoke control.

You'll want to look at NFPA 92A and 92B if you haven't already.

You can get a copy of the Siemens guide here.

 

[mstrlucky74]

Thanks guys.

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