Inquiry: |
05-04 |
Subject: |
Common vertical vent maximum size |
Submitted by: |
Nirmal Jain, Building Code Representative |
Approved by: |
Thomas R. Joachim, State Building Official |
Issue Date: |
December 15, 2005
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Question: |
What is the maximum size of a common vertical vent with two fan- assisted appliances.
What is the maximum size of a common vertical vent with two appliances, one natural draft and one fan-assisted.
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Answer: |
Minnesota Rule, Chapter 1346.5504.3.15:
With two fan-assisted appliances or a combination of a fan-assisted & natural draft appliance, the maximum size of a common vertical vent will be no greater than four times the area of the smallest vent.
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Comments: |
The sizing is verified as follows:
Two fan-assisted appliances:
For a given common vertical vent size, the Btu/hr. input capacity of the smallest fan-assisted appliance will be within the min/max range per 2000 IFGC tables 504.2(1) and 504.2(2).
Two appliances, one natural draft and one fan-assisted:
For a given common vertical vent size, the Btu/hr. input capacity of the fan-assisted appliance will be within the min/max range per 2000 IFGC tables 504.2(1) and 504.2(2).
Notes:
1. |
It may be necessary to change the vent connector from single wall to double wall in order to meet the requirements of the tables. |
2. |
Total input of both appliances must be less than or equal to the maximum value requirements according to tables 504.3(1) and
504.3(2) under the common vent capacity sections. |
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