NTI INSTALLATION MANUALS

Part 5 - Venting

Snorkel Venting (Two Pipe Sidewall Venting Terminations Beneath an Overhang)

Venting Below Grade

For installations that exit the wall below grade: 1. Excavate the site to a point where the pipes are to exit as shown in Figure 44. 2. Ensure the wall is fully sealed where the pipes penetrate. 3. The exhaust vent / air intake piping MUST be secured to the side of the building above grade, as shown, to provide rigidity. 4. Ensure that the exhaust vent / air intake clearances are maintained.

Supports every 24” [6 10 mm]

12” [30 5 mm] plus snow allowance above grade

Air-Inlet

Figure 44 - Venting Below Grade

Outdoor Venting

Vent piping outside the building is permitted under the following conditions: 1. The maximum length outside the building is 20 feet (6.1 m). Note that outdoor length must be included in the overall vent length calculation. 2. All normal termination clearances are maintained. 3. The pipe is supported every 24” (610 mm). 4. The exhaust and air intake are sloped back to the boiler 1/2” elevation for every linear foot (13 mm for every linear 305 mm).

Figure 43 - Two Pipe Sidewall (Horizontal Snorkel) Venting

Gas Vent Directly Below Keep Free of Obstructions

NOTES: A. For every 1” of overhang, the exhaust vent must be located 1” vertical below the overhang (12” minimum). Overhang means top of building structure (roof) and not two adjacent walls (corner of building). B. Maintain minimum separation between exhaust vent and air intake sidewall terminations, as required by local codes. C. Maintain 12” minimum clearance above highest anticipated snow level or grade (whichever is greater). D. The exhaust vent must extend a minimum of 12” to a maximum of 24” beyond the building. NOTE: These drawings are meant to demonstrate system venting only. The installer is responsible for all equipment and detailing required by local codes.

ned.

Exhaust Vent

mm

Maximum of 20 ft [6.1 m] is permitted for piping outside a building.

Figure 45 - Outdoor Venting

46