Air barriers bewteen levels in vertical chases?

[lumberg]

Hi. In redoing my bathroom, which shares a wall with a vertical chase compartment for the trunk lines of the HVAC system, I notice that sheet metal has been carefully cur and formed to create pretty close to an airtight seal beween levels.

I don't understand this. Why would it matter?

This bathroom is on the third floor of a townhouse so the ducts are the ends of the main trunk lines. They both go up into the attic before splitting apart.

[beenthere]

Any air that leaks out of a supply duct is air not deliver to a room, and it also creates a negative pressure in the house, and draws in unconditioned outside air.

On a return it will draw in air from that chase and create a positive pressure in the house, and force the conditioned air out of the house through any unsealed opening it can.


bottom line, cost you more money to heat or cool your house.

[tcktech]

Sheet metal is a fire brake in the chase. If there is a fire on a lower level it will not go up the chase to the attic.

[beenthere]

Miss read what he said.

[Freezeking2000]

Originally posted by tcktech
Sheet metal is a fire brake in the chase. If there is a fire on a lower level it will not go up the chase to the attic.

yep!

[lumberg]

AAAAAH! Thank you! I thought it was to create an airtight seal and metal was used because it's easy to work with. The fire protection aspect didn't even cross my mind!

That's why I'm here. Thank you!

[lumberg]

By the way--looks like the last plumber to work there should have used his own special, portable fire brake (or is it break?):

http://officelinebacker.atothosting.com/Bath/Valve/Valve6.JPG

Note the piece of permanent fire break slid up over chimney/flue to level of valve.

I would assume that the structural integrity of the sheet metal doesn't hurt when it comes to holding the ducts and flue in steady relationship to each other and the sides of the chase?

[lumberg]

Hall of shame material?