Silencer Holes

[LGreene]

Hollow metal frames are prepped at the factory for silencers - the small grey rubber mutes that make it a little quieter when the door closes. The holes are 9/32" in diameter, and they are on the side of the frame stop where the door contacts the frame. On single doors there are 3 holes, on pairs there are typically 2 holes, although some catalogs show 4 holes for a pair.

When a fire rated hollow metal frame has smoke gasketing that mounts in the same area as the silencers, the silencers are not installed and the gasketing is installed instead. This leaves the silencer holes open, although they would be under the adhesive gasketing. I have been asked if these "open holes" would be a deficiency on a fire door assembly, because one of the fire door inspection criteria is that there are no open holes in the assembly.

My gut reaction is that the open silencer holes would not be an issue because during the fire test the silencers would have melted away at some point, leaving the open holes, and the assembly was able to pass in that condition. Common sense tells me that having smokeseal installed over the holes wouldn't affect the performance of the assembly. But NFPA 80 doesn't address this specifically, and says that any open holes left after removing hardware have to be filled with steel fasteners (etc., etc.). There are definitely people out there who would not agree with my assessment that the holes covered by gasketing are ok.

What say you? Any logical arguments on either side of the discussion? If you're thinking this is a crazy question, welcome to my world.

Here's a catalog cut of a silencer: http://www.iveshinges.com/CatalogCuts/Ives-SR64.pdf

 

[mark handler]

The testing and listing is done with the holes.... Not an issue.

 

[cda]

Seem like it would be a question back to the manufacturer

In what configuration was the door tested??? And What should be done when smoke gasket is in place

Seems like they should be sealed, but have not seen a door test, I assume the door is latched during the test, so that frame area is protected

Than there are people who dream about doors;;;

http://www.door-hardware-genius.com/?p=63

 

[LGreene]

Than there are people who dream about doors;;;http://www.door-hardware-genius.com/?p=63

I know the Door Hardware Genius. :ugeek: It's a small world.

 

[Builder Bob]

Just a simple minded observation - what is the difference between a friction fit rubber stopper (silencer) and a big long piece of rubber gasketing for smoke seal? the holes are there anyway and most of the time in office and school enviroments, little gremlins usually borrow these stopper to either throw at somebody or to irritate somebody so their door rattles when they shut it....

Like I said, just a simple minded observation ---

(BTW, I was once a gremlin mention above - guilty of both accounts

 

[Doorman]

Why are the silencer holes open?

Most (an emphasis on most, I have not checked them all) of the bulb type gasket manufacturers suggest a wipe seal for the head and strike jamb, and a compression seal at the hinge jamb. When installed as a wipe seal, the silencers can remain and will function as intended.

This Tech Data Sheet for Pemko S88 gasket indicates the preferred method is for wipe seal installation. As can be seen, wipe seal (in the perfect world) does not interfere with silencer installation. As further indicated there, it is acceptable to install as a compression seal. This method would create the interference with silencers discussed here. In that circumstance, the silencer holes are covered. IMHO, this open hole (covered but not plugged) would not compromise the rating of the opening.

 

[LGreene]

What is the difference between a friction fit rubber stopper (silencer) and a big long piece of rubber gasketing for smoke seal?

Either the silencer or the gasketing would be fine...it's when neither are installed that it becomes a problem because of alignment of the door within the frame. It affects the way the latch seats into the strike.

 

[LGreene]

Doorman: Why are the silencer holes open?

There are some types of gasketing (like the NGP 5020) that would prevent the silencers from being installed.

 

[LGreene]

Seem like it would be a question back to the manufacturer

I checked with one manufacturer and they sent me a letter stating:

To whom it may concern,

In cases in which a frame stop is prepped for use with rubber mutes, it is acceptable for those holes to remain, if fire-rated gasketing is installed. The presence of the holes under that gasketing will not negatively affect the fire rating of that opening. If you have any questions or concerns about this, please contact me.

 

[mark handler]

The testing and listing is done with the holes.... Not an issue.

Hummmmm.....

 

[tbreese]

Legal, but not advisable

I agree with you, Lori, but I'd like to point out that most adhesive seals mounted as a compression seal to the stop face of the frame do not provide the spacing that silencers provide. If the frame is installed perfectly plumb and square, the latchbolt basically swims around in the strike because the door isn't being pushed away from the stop face. Also, the bulb gasket performs unreliably in real-world frame installations -- the door can break contact with the seal if the door face and the stop face are not parallel, or if there's fairly strong positive pressure on the push side of the doorallowing light/sound/smoke/gasses to leak. One other point is that most of the bulb manufacturers do not warrant their seals' adhesives.

Bottom line: stop-face mounted bulb seals are a cheap and inefficient, but "legal", way to comply with code.

TB

Hollow metal frames are prepped at the factory for silencers - the small grey rubber mutes that make it a little quieter when the door closes. The holes are 9/32" in diameter, and they are on the side of the frame stop where the door contacts the frame. On single doors there are 3 holes, on pairs there are typically 2 holes, although some catalogs show 4 holes for a pair.When a fire rated hollow metal frame has smoke gasketing that mounts in the same area as the silencers, the silencers are not installed and the gasketing is installed instead. This leaves the silencer holes open, although they would be under the adhesive gasketing. I have been asked if these "open holes" would be a deficiency on a fire door assembly, because one of the fire door inspection criteria is that there are no open holes in the assembly.

My gut reaction is that the open silencer holes would not be an issue because during the fire test the silencers would have melted away at some point, leaving the open holes, and the assembly was able to pass in that condition. Common sense tells me that having smokeseal installed over the holes wouldn't affect the performance of the assembly. But NFPA 80 doesn't address this specifically, and says that any open holes left after removing hardware have to be filled with steel fasteners (etc., etc.). There are definitely people out there who would not agree with my assessment that the holes covered by gasketing are ok.

What say you? Any logical arguments on either side of the discussion? If you're thinking this is a crazy question, welcome to my world.

Here's a catalog cut of a silencer: http://www.iveshinges.com/CatalogCuts/Ives-SR64.pdf

 

[LGreene]

Hi Tom -

We don't usually use bulb gasketing - we use something like the NGP 5020. What's your preferred solution for doors that require smoke seal?