Sizing Guide

www.hartandcooley.com Sizing Guide 21
1
Figure 14
USE INDIVIDUAL VENT FOR
TOP-FLOOR APPLIANCE IF
CONNECTOR REQUIREMENT
FOR RISE OR TOTAL HEIGHT
CANNOT BE MET (Table 1 or 2)
USE CONNECTOR DESIGN
TABLE (Table 4A or 5A)
TOP-FLOOR APPLIANCE
USE CONNECTOR DESIGN
TABLE (Table 4A or 5A)
THIRD-FLOOR APPLIANCE
USE CONNECTOR DESIGN
TABLE (Table 4A or 5A)
SECOND-FLOOR
APPLIANCE
FIRST-FLOOR APPLIANCE
APPROVED TOP
USE TOTAL HEIGHT FOR TOP-FLOOR
APPLIANCE AND COMBINED INPUT
OF ALL APPLIANCES ON COMMON
VENT (Table 4B or5B)
THIRD INTERCONNECTION TEE*
USE TOTAL HEIGHT FOR THIRD-
FLOOR APPLIANCE AND COMBINED
INPUT OF THREE APPLIANCES; IF
TOP-FLOOR APPLIANCE IS NOT
CONNECTED, MEASURE TOTAL
HEIGHT TO VENT TOP (Table 4B or 5B)
SECOND INTERCONNECTION TEE*
USE TOTAL HEIGHT FOR SECOND-
FLOOR APPLIANCE AND COMBINED
HEAT INPUT OF TWO APPLIANCES
(Table 4B or 5B)
FIRST INTERCONNECTION TEE*
DESIGN CONNECTOR FOR
FIRST-FLOOR APPLIANCE AS AN
INDIVIDUAL VENT OF THIS TOTAL
HEIGHT, FOR INPUT OF FIRST-
FLOOR APPLIANCE (Table 1 or 2)
*EACH INTERCONNECTION TEE IS THE SAME SIZE AS
PORTION OF COMMON VENT DIRECTLY ABOVE.
PRINCIPLES OF DESIGN OF MULTISTORY VENTS USING
VENT CONNECTOR AND COMMON VENT DESIGN TABLES
TEE WITH CAP OPTIONAL
TOTAL
HEIGHT FOR
TOP-FLOOR
APPLIANCE
TOTAL
HEIGHT FOR
THIRD-FLOOR
APPLIANCE
TOTAL
HEIGHT FOR
SECOND-FLOOR
APPLIANCE
RISE
RISE
RISE
However, if the heater on the top floor is vented
separately, Table 7 shows the result of increasing the
Minimum Total Vent Height of the third-floor appliance
to 16 feet and decreasing total input to the common
vent to 270,000 BTU per hour.
Table 7 indicates the economics of venting the top floor
separately, which eliminates the larger sizes of vent
pipe and the use of costly increasing fittings.
Type B Double-Wall Gas Vents
Table 6
Min.
Input Available Total Common
Total BTUH Connector Vent Connector Vent
Appliance To Common Vent Rise Height Size Size
1 90,000 10' 10' 5" with up to 10' lateral self-venting connector
2 180,000 1' 10' 6" 7"
3 270,000 1' 10' 6" 8"
4 360,000 1' 6' 6" 10"