This wall thimble is expandable and can be used with walls 4" to 7" thick. It also features a locking band on the interior to hold venting pipe in place. These stainless steel heater vent pipe and fittings feature patented built-in mechanical locking band and high-temp silicone gaskets. All pipe and fittings are UL1738 approved for category II, III and IV venting applications.
What is UL 1738? In short, it is a US standard for gas venting systems required in category 3 applications. Category 3 refers to positive vent pressure which is created by exhaust blowers in unit heaters. These vent systems must be constructed of corrosion resistant stainless steel, contain gaskets for sealing, and have a built in mechanical locking band among other requirements. All category 3 vent pipe and fittings offered are single wall.
Features
- Made of 316L corrosion resistant stainless steel
- Built-in high temp silcone gaskets for air tight seal
- Built-in locking band to insure a secure fit (no hardware needed)
- UL1738 approved for category 3 venting applications