Fire Alarm Shut Down Relay/Contactor

[flengineer]

I have a ductless minisplit that is installed as supplemental A/C in a kitchen with a larger A/C unit. The minisplit needs to shut off with the fire alarm system. I am specifying a fire alarm relay module to provide the control signal, but can I just have a regular contactor do the shut-off or does it need to be an NFPA 72-approved device (if that exists)? Due to the unit's size, it has no starter. Would it be better to provide a shunt trip breaker (2P15A) at the panel and have the fire alarm disconnect power at the breaker?

Also, am I correct in assuming the relay module will have a negligible affect on the voltage drop of the fire alarm circuit and on the current draw on the battery?

 

[MEP_PM]

You may want to double check the shut down requirements with your Mechanical Engineer or AHJ. In some areas, units under 2000cfm are not required to shut down on FA. I believe most mini splits are under 2000cfm. Not an expert in this area but generally don't see FA relays shutting down Mini splits. You may have a special case or maybe we have some local exceptions.

 

[flengineer]

Since there is a unit over 2000 CFM in the room, all units in the room must shut off, regardless of size.

 

[gadfly56]

Since there is a unit over 2000 CFM in the room, all units in the room must shut off, regardless of size.

Unless I missed it, no information is given regarding either unit's capacity. Your assertion, though possibly true, is unfounded.

If this is a residential application the shutdown is unlikely to be required in any case.

To answer the original question, no, the contactor does not have to be listed for fire alarm use. Also, I prefer not to use shunt trip breakers when avoidable. If the power to the shunt coil fails, you'll never know until you do a system test, or the A/C unit fails to shut down on alarm.

 

[hurk27]

Since there is a unit over 2000 CFM in the room, all units in the room must shut off, regardless of size.

The whole idea of shutting down air moving systems is to prevent smoke and fire from being blown into other areas of a building, a mini-split does not have this capacity since it is a stand alone unit and is not ducted to any other part of the building, requiring this to be shut down would be like requiring all refrigerators and freezers to also be shut down??

 

[RICK NAPIER]

If your using the 2009 IMC these are the sections that would apply. It would seem that you may not need to install a relay because of 606.2 exception and 606.2.1.

606.2 Where required. Smoke detectors shall be installed where indicated in Sections 606.2.1 through 606.2.3.

Exception: Smoke detectors shall not be required where air distribution systems are incapable of spreading smoke beyond the enclosing walls, floors and ceilings of the room or space in which the smoke is generated.

• 606.2.1 Return air systems. Smoke detectors shall be installed in return air systems with a design capacity greater than 2,000 cfm (0.9 m³/s), in the return air duct or plenum upstream of any filters, exhaust air connections, outdoor air connections, or decontamination equipment and appliances.
  
  Exception: Smoke detectors are not required in the return air system where all portions of the building served by the air distribution system are protected by area smoke detectors connected to a fire alarm system in accordance with the International Fire Code. The area smoke detection system shall comply with Section 606.4.

 

[flengineer]

Applicable code is the Florida Building Code which does not include an exception for a unit in a single room. In any event, this is in a school and the school system reviewer (who cannot be argued with successfully) is requesting the shut-down. The job hasn't bid yet, so it's going in.

 

[david luchini]

Applicable code is the Florida Building Code which does not include an exception for a unit in a single room. In any event, this is in a school and the school system reviewer (who cannot be argued with successfully) is requesting the shut-down. The job hasn't bid yet, so it's going in.

The Florida Mechanical Code (Section 606) requires essentially the same thing as posted by Rick in post #6, except that it requires detection in the supply air rather than the return air. There is no requirement in the Florida code to shut down ductless split units.

But I understand your point about not being able to argue with reviewers.