inspectorwill Posted August 19, 2009 Report Share Posted August 19, 2009 I am hoping to settle this issue once and for all. B vents require 1" clearance from combustible materials. Old transite typically requires 1 1/2" clearance from combustible materials. Most homes over ten years old have vents in contact with the drywall at the water heater or furnace closet ceiling. Drywall (gypsum) is rated for use as fire separation but considered combustible material per the UMC. Was there a change in the UMC at some point? Please see the photos attached for examples. All feedback is much appreciated. Click to Enlarge 55.92 KB Click to Enlarge 55.98 KB Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted August 19, 2009 Report Share Posted August 19, 2009 I am hoping to settle this issue once and for all. B vents require 1" clearance from combustible materials. Old transite typically requires 1 1/2" clearance from combustible materials. Most homes over ten years old have vents in contact with the drywall at the water heater or furnace closet ceiling. Drywall (gypsum) is rated for use as fire separation but considered combustible material per the UMC. Was there a change in the UMC at some point? Please see the photos attached for examples. All feedback is much appreciated. I think the change is related more to enforcement than to changes in the codes. - Jim Katen, Oregon Quote Link to comment Share on other sites More sharing options...
Darren Posted August 19, 2009 Report Share Posted August 19, 2009 Attached see New Jersey's take on this subject. Also note the date of the original release is 1990. Download Attachment: b_90_3.pdf 29.85 KB Quote Link to comment Share on other sites More sharing options...
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