8
SPECIAL INSTALLATION EXAMPLE |
| OFFSET INSTALLATION EXAMPLE |
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When a horizontal offset is required in a
In an installation as shown in FIGURES 9 & 12, lengths A and C are known based on room height and roof require- ments.
Length C must never be less than 29 inches. Any 90° and 45° elbows must be calculated as 5 feet of venting each.
The allowable horizontal run can be calculated using these parameters. In this example, the total vertical height is 20 feet (length "A" is required to be 11 feet while length "C" needs to be 9 feet). The maximum vertical length is 40 feet and all runs and elbows must be sub-
tracted from this maximum vertical FIGURE 9 length.
The maximum allowable horizontal run that "B" can be is:
40 ft. (maximum vertical run length)
- 9 ft. (vertical run "C")
10 ft. (maximum allowable horizontal length for "B")
The length of "B" must never be greater than the length of "A" and "C" combined.
The maximum allowable horizontal run that "A" in Figure 13 can be is:
40 ft. (maximum vertical run length) - 7 ft. (horizontal run "B")
33 ft. (maximum allowable vertical length for "A")
FIGURE 10
If a first run of 120 inches is re- quired, using the "First Vent Run" on the chart shows that a maxi- mum second run of 60 inches is allowable.
IF NECESSARY, THE FIRST
FIGURE 11
RUN AND THE SECOND
RUN MAY BE REVERSED.
FIGURE 12
FIGURE 13
