premade passive floor/ceiling vents?

[lesf]

About 10 years ago in a previous house, I purchased a "pre-made" passive vent to go between floors.

It was a very simple design, basically 2 vents with springs on the ceiling side to hold the vent/register in place.
2 pieces of sheet metal that formed the 'duct' that slid in and out to adjust for the thickness of the
floor. Thats it.. Yeah I know I could probably make something but by the time you find the pieces
and make it, sometimes it costs more anyway.

Has anyone seen something like this for sale recently? I have googled off and on trying all kinds
of word combinations. No luck

Thanks!
Les F

 

[LLigetfa]

Most modern fire codes frown on that sort of thing. Today the thing to do is to install fire rated fusible dampers.

 

[lesf]

that may explain the lack of them on the market... so is there a 'safer' version available?

 

[Gooserider]

that may explain the lack of them on the market... so is there a 'safer' version available?

Yes - the problem with the open vents was that they potentially provided a path for rapid fire spread through what would otherwise be a barrier that would stop the flame spread for some minutes... They also provide a path for smoke and other fumes, but that is harder to stop.

Essentially the safer version has some spring loaded flaps in it, which are held open by a "fusible link" type connection, such that if the heat in the vent area goes to high, the link melts and the flaps snap shut, at least in theory blocking the flame spread...

Not sure on sources, but a good HVAC supply place should be able to find them...

Gooserider