Rossn
Member
I'm installing a residential range hood exhaust system.
It includes a (used) 54" Wolf island range hood, 10" ducting, and a Broan 335 rooftop mounted 1200 CFM variable speed blower. The ducting run (including 2' below ceiling level) is about 15' long, and consists of 10" rigid duct, 3 long-radius 5-gore elbows (2 at 90, one slightly less), and a Fantech LD10 duct silencer.
A diagram is shown below, with a few pics of the space.
I have a few install questions...
Q1: Vibration management - is there any value in using dampened hangers for the suspended duct, given the two ends (blower and hood) are attached to the structure? I assume there isn't a canvas that meets M1503. Note: I've had mechanical vibration issues before, and appreciate their potential severity.
Q2: Duct supports - I assume for the shown space, it will be better for vibration to support with hangers, versus supported from underneath. I will be wrapping the duct in fiberglass duct wrap (likely R8). What's the best way to suspend the wrapped duct (both vibration and thermal considered)? I'm planning on one hanger at each end of the duct silencer, and one at the elbow nearest the range hood. Is that acceptable?
Q3: Internal fasteners - the attic will basically be inaccessible. Where the ducting attaches to the roof mounted fan, I'd like to fasten the duct to the fan, using internal fasteners. This is to allow potential replacement of the fan on the roof, and by removing the fan motor, the fasteners could be removed. Are typical screws acceptable for this use and meet code, or should I consider pop rivets installed from the inside?
Thanks in advance!
Note: Duct silencer shown is near final location, perhaps a couple inches suspended.
It includes a (used) 54" Wolf island range hood, 10" ducting, and a Broan 335 rooftop mounted 1200 CFM variable speed blower. The ducting run (including 2' below ceiling level) is about 15' long, and consists of 10" rigid duct, 3 long-radius 5-gore elbows (2 at 90, one slightly less), and a Fantech LD10 duct silencer.
A diagram is shown below, with a few pics of the space.
I have a few install questions...
Q1: Vibration management - is there any value in using dampened hangers for the suspended duct, given the two ends (blower and hood) are attached to the structure? I assume there isn't a canvas that meets M1503. Note: I've had mechanical vibration issues before, and appreciate their potential severity.
Q2: Duct supports - I assume for the shown space, it will be better for vibration to support with hangers, versus supported from underneath. I will be wrapping the duct in fiberglass duct wrap (likely R8). What's the best way to suspend the wrapped duct (both vibration and thermal considered)? I'm planning on one hanger at each end of the duct silencer, and one at the elbow nearest the range hood. Is that acceptable?
Q3: Internal fasteners - the attic will basically be inaccessible. Where the ducting attaches to the roof mounted fan, I'd like to fasten the duct to the fan, using internal fasteners. This is to allow potential replacement of the fan on the roof, and by removing the fan motor, the fasteners could be removed. Are typical screws acceptable for this use and meet code, or should I consider pop rivets installed from the inside?
Thanks in advance!
Note: Duct silencer shown is near final location, perhaps a couple inches suspended.