D. How to Use the Vent Graph | E. Venting Guidelines |
1.Measure the distance from the top of appliance to the center of the 90° elbow. On the graph below, draw a horizontal line from that measurement on the vertical axis across until it intersects with the slanted line.
2.From the point of this intersection, draw a vertical line to the bottom of the graph.
3.The point at which this line meets the bottom line of the graph is the maximum length of the horizontal run.
Example 1: If the vertical dimension from the top of the appliance to the center of the 90° elbow is 7 ft. (2m), the horizontal run to the base of the temination cap must not exceed 13 ft.- 2 in. (4m).
Example 2: If the vertical dimension from the top of the appliance is 21 ft. (6m), the horizontal run to the base of the termination cap must not exceed 7 ft.- 3in. (2m).
4.Each 90° elbow is equivalent to 3 ft. (914mm) of vent pipe and each 45° elbow is equivalent to 1 ft. (305mm) of vent pipe, and must be subtracted from vent pipe run. A single vertical to horizontal 90° elbow is already calculated into the allowable 15 ft. (5m) run. Each additional 90° elbow reduces the maximum horizontal distance by 3 ft. (914mm).
Example: The use of 3 elbows would reduce the allowable horizontal run to 9 ft. (3 - 1 = 2 elbows x 3 ft. = 6 ft.; 15 ft. max. - 6 ft.= 9 ft. max.)
Notes: The maximum horizontal vent run is 15 ft. (5m) when the vertical vent rise is 10 ft. (3m).
The minimum horizontal vent run is 11 in. (279mm).
Minimum wall thickness is 4 in. (102mm). Maximum wall thickness is 20 in. (508mm).
Horizontal sections require a 1/4 in. (6mm) rise for every 12 in. (305mm) of horizontal travel.
Exterior Vent Diameter =
Horizontal sections require noncombustible support every 3 ft. (914mm), e.g. plumbing tape.
EXCEPTION FOR REAR VENT KIT, HORIZONTAL
INSTALLATION:
When installing the Sapphire in a rear vent configuration with no vertical rise: a snorkel kit must be used, and a derating orifice must be installed. The appropriate orifice is supplied with the rear vent kit.
For any vertical rise when rear venting, a minimum of 2 ft. (610mm) vertical must be used prior to any horizontal run.
The maximum horizontal vent run is 2 ft. (610mm).
The maximum horizontal vent run with a 45° elbow is 14 in. (356mm).
No external minimum rise is required. The minimum horizontal vent run is 11 in. (279mm).
NOTE: IF YOUR INSTALLATION FALLS WITHIN A SHADED AREA ON THE GRAPH, THE DAMPER MUST BE USED.
NOTE: In the Commonwealth of Massachusetts, the word damper shall be replaced with the words flue restrictor.
TOP VENT GRAPH | REAR VENTING WITH VERTICAL RISE |
| 30' |
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| 30' |
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| 28' |
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| 28' |
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| 26' |
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| 26' |
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| 24' |
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EX. 2 |
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| 24' |
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22' |
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| 22' |
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| 20' |
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| 18' |
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VERTICAL DISTANCE |
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| 18' |
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16' |
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FROM APPLIANCE | 14' |
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| 16' |
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TOP TO 90° ELBOW |
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| 14' |
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| 12' |
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EX. 1 | 10' |
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| 12' |
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8' |
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| 10' |
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| 6' |
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| 8' |
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| 4' |
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| 6' |
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| 4' |
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| 0' | 11" | 2' | 4' | 6' | 8' | 10' | 12' | 14' | 15' | 2' |
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| (MIN) |
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| (MAX) | 0' |
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| TOTAL HORIZONTAL RUN TO BASE OF THE |
| 2' | 4' | 6' | 8' | 10' | |||||||
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| TERMINATION CAP (EXCLUDING ELBOWS) |
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Figure 5.2 |
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September 1, 2008 |
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| Page 11 | |||||||