Multiple Concentric Termination Clearances
When installing multiple concentric terminations vertically through a roof or horizontally through a sidewall ensure the required clearances (separation) between terminations are maintained. Ensure multiple terminations are arranged or grouped as required.
Note: These clearances must be maintained to prevent the recirculation of vent (exhaust) gases to the intake air. Clearances are measured between the edges of the concentric termination caps.
When installing multiple concentric terminations through a roof or through a sidewall the clearances shown in Figure 32 must be maintained.
See Multiple Concentric Termination Arrangements on page 31.
Close Proximity & Standard Clearance
1.The clearance between multiple termination caps must be 0 inches (touching) to a maximum of 2 inches (5 cm), dimension A - Figure 32, when installing concentric terminations in close proximity. See Figure 37 on page 31.
2.The clearance between multiple termination caps must be increased to a minimum of 24 inches (61 cm), dimension B - Figure 32, when installation in close proximity (above) is not possible. This is the standard clearance.
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A | TERMINATION CAPS |
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END VIEW |
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CLOSE PROXIMITY | STANDARD CLEARANCE |
A = 0 - 2 INCHES (0 - 5 cm) | B = 24 INCHES (61 cm) |
| OR GREATER |
TWO CONCENTRIC TERMINATIONS
(THROUGH A ROOF OR SIDEWALL)
Figure 32
Three Concentric Terminations
1.When installing three concentric terminations through a roof or through a sidewall the third termination may be installed in close proximity as indicated by dimension A in Figure 33.
2.If close proximity installation of the third termination is not possible the third termination may be installed as indicated by dimension B in Figure 33.
TERMINATIONCONCENTRIC | A | B |
CAPS END VIEW |
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A |
| THIRD |
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| TERMINATION |
A = 0 - 2 INCHES (0 - 5 cm) | B = 24 INCHES (61 cm) | |
CLOSE PROXIMITY | OR GREATER | |
THREE CONCENTRIC TERMINATIONS
(THROUGH A ROOF OR SIDEWALL)
Figure 33
Four Concentric Terminations
1.When installing four concentric terminations through a roof or through a sidewall in close proximity they may be arranged into stacked rows of two as shown in Figure 34 or lateral rows of two as shown in Figure 35.
2.Four is the maximum number of concentric terminations that may be installed in a group where all terminations are in close proximity as shown in Figure 34.
A
A | CONCENTRIC |
TERMINATION | |
CAPS END VIEW |
A = 0 - 2 INCHES (0 - 5 cm)
CLOSE PROXIMITY
FOUR CONCENTRIC TERMINATIONS
(THROUGH A ROOF OR SIDEWALL)
Figure 34
A B A
CONCENTRIC
TERMINATION
CAPS END VIEW
A = 0 - 2 INCHES (0 - 5 cm) | B = 24 INCHES (61 cm) |
CLOSE PROXIMITY | OR GREATER |
FOUR CONCENTRIC TERMINATIONS
(THROUGH A ROOF OR SIDEWALL)
Figure 35
Groups Of Terminations
1.When installing multiple groups of concentric terminations through a roof or through a sidewall in close proximity they can be installed into stacked groups of four as shown in Figure 36. Lateral groups of four as shown in Figure 35 may be a more convenient installation arrangement for multiple groups depending on available space.
CONCENTRIC
A B TERMINATION
CAPS END VIEW
A 
A = 0 - 2 INCHES (0 - 5 cm) | B = 24 INCHES (61 cm) |
CLOSE PROXIMITY | OR GREATER BETWEEN |
| GROUPS OF FOUR |
EIGHT CONCENTRIC TERMINATIONS
(THROUGH A ROOF OR SIDEWALL)
Figure 36
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