Fire Shutter / Door Question?

[jpranch]

Here is what I have. A 3 hour rated OH door. We are requireing auto closing with fire alarm and sprinkler flow interlock. The alarm guy and electrician are telling me that to make this happen they must over ride the safety sensors at the bottom of this door? The safety sensors they are talking about are the ones that prevent the door from closing if a person is under it. Sure could use some help on this. Thanks, jp

 

[cda]

Re: Fire Shutter / Door Question?

WELL how fast does it drop?

If the fire alarm or fire sprinkler are activating than potential problem and people should be leaving the building

also should be other personnel doors to use

also have not done a oh door in a long time but have not seen and sensors on older models, must be something in last few years

also if a rated door how does it release now if you did not require the fire alarm drop??

and how it releases now if the door goes down and hits something does it go back up and stay up or does it try to drop again???

sounds like they are blowing smoke some where!!!!!!!!!!!!!!!

 

[Coug Dad]

Re: Fire Shutter / Door Question?

A leading safety edge will prevent the door from closing in a non fire condition. Under a fire condition the leading safety edge will retract the door a few times, but then the door will close. I think the number of retractions is three before forced closing, but I would have to confirm that.

 

[Coug Dad]

Re: Fire Shutter / Door Question?

OK, I looked it up in NFPA 80. Section 11.4.2.2.3 (2010) specifies the three attempt rule.

 

[cda]

Re: Fire Shutter / Door Question?

nfpa 80 1999

6-3 Openings.

6-3.1 Frames.

Frames shall not be required for rolling steel door installations. Where frames or jambs are provided, only minimum 3/16-in. (4.76-mm) nominal structural steel or formed steel plate shall be used. Frames or jambs shall be in accordance with the door manufacturer’s listing.

6-4 Assembly Components.

6-4.1 Closing Devices.

6-4.1.1

An automatic-closing device shall be installed on every rolling steel door.

6-4.1.2

Rolling steel doors shall close automatically upon activation or release of a fusible link or detector.

6-4.1.3

The automatic-closing mechanism shall be enclosed in a metal housing to protect the mechanism from debris and ensure operation in the event of fire.

6-4.1.4

A governor, where employed on a door, shall be an integral mechanism working in coordination with the closing device and shall control the closing speed of the door.

6-4.1.5

Rolling steel fire doors shall have an average closing speed of not less than 6 in./sec (152 mm/sec) nor more than 24 in./sec (610 mm/sec).

MINIMUM 6 inches a second, so a ten foot high door would take 20 seconds??? to MAX 24 inches 5 seconds

so does the door meet NFPA 80??

 

[cda]

Re: Fire Shutter / Door Question?

11.4.2.2.3 When an automatic closing device is designed to open and reclose when encountering an obstruction, the unit shall be designed such that it can reopen a maximum of three times.

11.4.2.2.3.1 After encountering an obstruction for the third time, the bottom bar shall come to rest on the obstruction.

so it looks like you can ask for the fire alarm drop?

I go back to how is it designed to release from the maker??? fusible link??? and if so does the sensor come in to play???

 

[Coug Dad]

Re: Fire Shutter / Door Question?

the leading safety edge is only on a power operated door. A gravity door can, and should, have a governor so that the door does not drop so fast as to cause injury.

 

[cda]

Re: Fire Shutter / Door Question?

the leading safety edge is only on a power operated door

so does it motor operate to close under fire conditions???

 

[GNE]

Re: Fire Shutter / Door Question?

OH doors in the means of egress always seems like a poor idea-- maybe they can come up with a better approach.

 

[jpranch]

Re: Fire Shutter / Door Question?

The O.H. door is not part of the MOE. It is in a 3 hour fire barrier that separates high hazard from business and assembly. Because of the arangement I did not accept the fuseable link as an approved closing device. This door is 12 to 14' in height. By the time a link would melt the occupants would be dead.