The 4" wall thimble is used for many single wall pipe, horizontal vent exhaust applications. It can be used with natural gas or liquid propane, Category III appliances.
This 4" wall thimble is rigid pipe, using Category III Stainless Steel. The 4" wall thimble is adjustable from 4" up to 7" depending on your wall thickness. A wall thimble is used when the vent passes through a combustible horizontal opening. It is not required for non-combustible walls. The wall plates on either side are 10" x 10". This piping is UL 1738 / AL 29-4C rated.
Some appliances that use Category III Stainless Steel Single Wall Piping include:
- Unit Heaters
- Hi-Efficiency Gas Appliances (including furnaces and water heaters)
- Engineered for use with Category II, III and IV gas-burning appliances only, where the maximum vent gas temperature at the appliance outlet does not exceed 550°F (288°C).
This venting requires 3” clearance to combustibles.
- Gasketed connections
- UL 1738 Rated
- Fusion welded pipe seams
- No sealant required, no cure time, or no call backs
- Air tight seam, smooth finish, better fit
- Metallic special gas vent cut to length on site
- Highest pressure rating in the industry greater than five time the industry standard
Always check your local codes before installing any vented appliance.
Below is an illustration of the 4" wall thimble dimensions.