Vent and Chimney Sizing

4 November 2016

Reference #:  D-G5 071030 6 Rev 01

General Details

This directive is being issued  to address the application of the requirements for vent sizing in CSA B149.1 clause 8.13.

Specific Details

When using the tables in Annex C to size vents for Category I appliances installed in locations where the outdoor design temperatures in the BC Building Code (extracted in enclosed table) are -10OC or lower, the smallest permitted vent size shall be used. The smallest vent size improves venting and reduces the potential for condensation promoting effective venting and facilitating conformance with B149.1 8.10.1.

For locations where an outdoor design temperature is not listed in the BC Building Code the outdoor design temperature of the closet location should be used.

Brad Wyatt
Provincial Safety Manager - Gas

References:
Safety Standards Act
Gas Safety Regulation
CSA B149.1 - Natural gas and propane installation code
BC Building Code - 2012 

Outdoor Design Temperatures extracted from BC Building Code 2012 Edition

Reference: 2.5% January design temperature value ordinarily used in the design of heating systems

Location

Temp

(OC)

Location

Temp

(OC)

Location

Temp

 (OC)

100 Mile House

-30

Kelowna

-17

Sidney

-4

Abbotsford

-8

Kimberley

-25

Smith River

-45

Agassiz

-9

Kitimat Plant

-16

Smithers

-29

Alberni

-5

Kitimat Townsite

-16

Sooke

-1

Ashcroft

-24

Ladysmith

-7

Squamish

-9

Bamfield

-2

Langford

-4

Stewart

-17

Beatton River

-37

Lillooet

-21

Tahsis

-4

Bella Bella

-5

Lytton

-17

Taylor

-35

Bella Coola

-14

Mackenzie

-34

Terrace

-19

Burns Lake

-31

Masset

-5

Tofino

-2

Cache Creek

-24

McBride

-29

Trail

-14

Campbell River

-5

McLeod Lake

-35

Ucluelet

-2

Carmi

-24

Merritt

-24

Vancouver Region

 

Castlegar

-18

Mission City

-9

Burnaby (Simon Fraser Univ.)

-7

Chetwynd

-35

Montrose

-16

Cloverdale

-8

Chilliwack

-9

Nakusp

-20

Haney

-9

Comox

-7

Nanaimo

-6

Ladner

-6

Courtenay

-7

Nelson

-18

Langley

-8

Cranbrook

-26

Ocean Falls

-10

New Westminster

-8

Crescent Valley

-18

Osoyoos

-14

North Vancouver

-7

Crofton

-4

Parksville

-6

Richmond

-7

Dawson Creek

-38

Penticton

-15

Surrey (88 Ave & 156 St.)

-8

Dease Lake

-37

Port Alberni

-5

Vancouver

(City Hall)

-7

 

Dog Creek

-28

Port Alice

-3

Duncan

-6

Port Hardy

-5

Vancouver

(Granville & 41 Ave)

-6

 

Elko

-28

Port McNeill

-5

Fernie

-27

Port Renfrew

-3

West Vancouver

-7

Fort Nelson

-39

Powell River

-7

Vernon

-20

Fort St. John

-35

Prince George

-32

Victoria Region

 

Glacier

-27

Prince Rupert

-13

Victoria

(Gonzales Hts)

-4

 

Gold River

-8

Princeton

-24

Golden

-27

Qualicum Beach

-7

Victoria

(Mt Tolmie)

-6

 

Grand Forks

-19

Queen Charlotte City

-6

Greenwood

-20

Quesnel

-31

Victoria

-4

Hope

-13

Revelstoke

-20

Whistler

-17

Jordan River

-1

Salmon Arm

-19

White Rock

-5

Kamloops

-23

Sandspit

-4

Williams Lake

-30

Kaslo

-17

Sechelt

-6

Youbou

-5