Equivalent Vent Length (EVL)
The longer the run of pipe in your installation, the more restriction
there is in the system. Therefore, larger diameter pipe should be
used.
• Use 4” pipe if you have more than 15 feet of Equivalent Vent
Length (EVL).
• Horizontal runs shall not exceed 10 feet of EVL.
• To calculate EVL, use the following conversions table:
Qty Type of pipe EVL equivalent(ft)
1 90° elbow or “T” 5
1 45° elbow 3
1 ft Horizontal pipe run 1
1 ft Vertical pipe run 0.5
NOTE: At altitudes above 3,000 feet, we suggest the use of 4”
diameter vent at an EVL of 7 feet or more.
Here is an example on how to calculate the EVL of your installation.
(See Figure 8)
(3 x 4’ of vertical length = 12’ x 0.5 = 6 EVL) + (1 x elbow or "T" = 5
EVL) + (2 x 1’ of horizontal length = 2 EVL)
Total EVL = (6 + 5 +2) = 13. So 3” diameter vent is allowed
INSTALLATION CONFIGURATIONS
A. HORIZONTALLY THROUGH WALL (refer to Figure 7 & 8 )
NOTE: Follow the vent manufacturer’s instructions.
1. Position stove, adhering to clearances shown in Figures 1 & 2.
2. Locate position of hole in wall; directly behind stove exhaust
vent (refer to figure 4).
3. Always maintain 3” clearance from combustible materials.
4. Install a wall thimble as per the vent manufacturer’s
instructions.
5. Attach enough piping to penetrate and extend at least 6”
beyond exterior walls. An 8-foot vertical pipe run is suggested
where possible to reduce the possibility of smoke spillage in
the event of a loss of negative pressure.
6. Attach cap and seal outside wall thimbles with non-hardening
waterproof mastic.
Termination should not be located so that hot exhaust gases can
ignite trees, shrubs, or grasses or be a hazard to children. Exhaust
gases can reach temperatures of 500ºF and cause serious burns if
touched.
WALL
THIMBLE
CLEAN OUT
TEE
FOLLOW CHIMNEY OR
VENT MANUFACTURER'S
INSTRUCTIONS
90 DEGREE ELBOW
45 DEGREE ELBOW
TERMINATION
COLLAR
WALL
STRAP
COUPE-FEU
MURAL
1' HORIZONTAL RUN EVL = 1' 1' HORIZONTAL RUN EVL = 1'
VERTICAL ROOF VENT
WALL
STRAP
CLEAN OUT
TEE
VERTICAL LENGTH4' EVL = 4 X 0.5' = 2'
VERTICAL LENGTH 4' EVL = 4 X 0.5' = 2'
VERTICAL LENGTH 4' EVL = 4 X 0.5' = 2'
90° ELBOW "T" LEE = 5'
FOLLOW CHIMNEY OR
VENT MANUFACTURER'S
INSTRUCTIONS
Locate terminations: a) not less than 3 feet above any forced
air inlet located within 10 feet; b) not less than 4 feet below
or horizontally from, or one foot above, any door, window or
gravity air inlet into any building; c) not less than two feet
from an adjacent building and not less than 7 feet above
grade when located adjacent to a public walkway. Mobile
home installations must use a spark arrester. Other
restrictions may apply, such as the need to maintain a
minimum distance to a gas meter. US and Canadian
Standards may vary. Consult the vent manufacturer’s
instructions.
IN
S
TALLATI
O
N
7