Publisher’s version / Version de l'éditeur:
Technical Note (National Research Council of Canada. Division of Building Research), 1959-03-25
READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.
https://nrc-publications.canada.ca/eng/copyright
Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.
Questions? Contact the NRC Publications Archive team at
PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.
Archives des publications du CNRC
For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous.
https://doi.org/10.4224/20358820
Access and use of this website and the material on it are subject to the Terms and Conditions set forth at
Requirements for Venting of Fuel Fired Appliances in the National Building Code Compared to Those in C.S.A. Standards B 139 and B 149
Kent, A. D.; Wilson, A. G.
https://publications-cnrc.canada.ca/fra/droits
L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.
NRC Publications Record / Notice d'Archives des publications de CNRC: https://nrc-publications.canada.ca/eng/view/object/?id=41e8292f-6a76-479f-855f-91f9f88077cf https://publications-cnrc.canada.ca/fra/voir/objet/?id=41e8292f-6a76-479f-855f-91f9f88077cf
NATIONAL RESEARCH COUNCIL OF CANADA
R.F.L. '
No.
275
ｍ｡ｲ｣ｾ 25, 1959.
FOR INTERNAL USE
NOTlE
/w
APPROVED BY CHECKED BYDIVISION OF BUILDING RESEARCH
'f
E
C
JH[
Ii
][
CAlL
A.D. Kent and A.G. Wilson
Heating Panel, Advisory Fire Group, ACNBC. DATE
PREPARED BY
NOT FOR PUBLICATION
PREPARED FOR
SUBJECT Requirements for Venting of Fuel Fired
Appliances in the National BUilding Code Compared to those in C.S.A. Standards
B 139 and B 149.
This note gives a comparison of requirements and
recommendations covering the venting of fuel fired appliances as contained in
1. National Building Code of Canada 1953 (NBC)
2. Canadian Standards Association Installation
Code for Gas Burning Appliances and Equipment (B149-1958)
3. Canadian Standards Association Installation
Code for Oil Burning Equipment (B139-1957)
In making the comparison some suggestions have been advanced for discussion purposes"
is to assist the Heating Panel in tions on venting requirements for National Building Code.
The purpose of this note the provision of
recommenda-the 1960 edition of the
Definitions
Chimney Definition in NBC essentially the same as in
B149 and B139. B149 also refers to "Type A"
under "flue or vent". It also refers to a fllined
chimney", which is perhaps unnecessary. .
The NBC definition restricts the use of the word "chimney" to masonry constructions and refers to "alternate chimney assemblies" for other types
(other than smokestacks or ventstacks). B139
refers to "prefabricated fluesll and gives a specific
requirement for these, while B149 refers to Itspecial flues" under "flues or vent" and gives the same requirement.
Perhaps chimneys should be considered in three categories:
Chimney, field-constructed - a primarily vertical masonry or reinforced concrete shaft, constructed in the field, which encloses one or more flues.
Chimney, factory-built - a chimney consisting
entirely of factory-constructed parts, each designed to be assembled with the others without requiring field construction.
Chimney, ｭ･ｴ｡ｬＧｾ a field-constructed chimney of
metal, sometimes referred to as a smokestack.
Draft Appears in Bl39 but not in NBC or B149.
Draft, mechanical same as above
Draft, natural ft
"
tIDraft, regulator tI
"
tIp.3 Flue Collar Appears in Bl39 and 149 with slight differences,
but not in NBC. Suggest the two definitions be
combined for NBC.
Flue Gas and Combustion Products - Defined in B149 but not in
NBC or B139.
p.3 Smokepipe Term appears in NBC but not in Bl39 or B149.
Bl39 uses term "flue pipe". NBC does not refer
specifically to solid or liqUid fuel presumably because a gas-fired applianoe, if oonvertible
p.3 Flue NBC and Bl39 are essentially in agreement but
Bl49 differs. The former refer to the
passage-way, while the latter refers to the enclosure
around the passageway. It should be made clear
in NBC whether this passageway is only that enclosed by the chimney or includes that between chimney
and appliance.
Draft Hood Bl49 definition is probably more explicit
than NBC. Suggest, however, that words "products
of combustion" in (a) of Bl49 definition should read "flue gas" since the definition of "combustion products" does not include excess air.
Venting
3
-to solid or liquid fuel, must use a smoke pipe in
NBC. The term "flue pipe" would seem preferable.
p.3 Vent Connector Pipe This term appears in NBC only.
B149
refers to "flue or vent connector". Perhapsthe term "vent pipe" might be preferable.
Otherwise, the definition in NBC appears satisfactory -the word "heatingllshould be omitted.
Appears in B149 but not B139 or NBC. The definition
is questionable.
Vented (appliance) and Unvented (appliance) - Appears in
B139
but not in NBC or B149. .
Ventstack Term used in NBC but not in B139 or B149. B149
under "Flue or vent ll refers to "Types Bit "Type BW"
and "Type Cit. These are referred to as hgas
Vents" in UL-44l. Note on Definitions
The following terminology is suggested for discussion purposes.
1. Solid and LiqUid Fuel Fired Appliances
(a) Flue, flue collar, flue pipe, chimney
(b) . Flue, flue collar, flue pipe, flue stack
2. Gas Fired Appliance
(a) Flue, flue collar, vent connector, vent
(b) Vent, vent collar, vent pipe, vent stack
Terminology in l(a) and 2(a) is thought to best represent common usage, while that in l(b) and 2(b) provides a parallel system of definitions for the two appliance groupings.
6.2.3.7.4 Para 5, polS, NBC requires no flue or smoke pipe
for oil burning appliances of less than 20,000
BTU/hr. for intermittent use. B139 (3-15) requires
no flue connection for certain "approvedll
portable heaters and stoves but details of operation,
installation and venting are carefully outlined in Secti. on 13.
B149 allows not
6.2.3.9.2
Last para, p.20, requires appliances to !tbe
installed in locations in which the ｾ｡｣ｩｬｩｴｩ･ｳ ｾｯｲ
ventilation permit ｳ｡ｴｩｳｾ｡｣ｴｯｲｹ combustion ｯｾ
gas and proper venting under normal conditions ｯｾ
useu, Clauses 1.50105 and 1.5.1.6 in B149 are
more explicit.
1st para, p.21, Terminology Ｂｾｬｵ･ｳｲｴ etc. might
need changing ｩｾ ､･ｾｩｮｩｴｩｯｮｳ altered.
p.21 (a) ａｐｾｩ｡ｮ｣･ｳ requiring ｾｬｵ･ｳＮ {change
to vents?)d gives two exceptions and then lists
the types ｯｾ appliances which shall have ｶｾｮｴｳ
while B149 (105.2) gives only the exceptions.
would ｡ｰｰ･｡ｾ to be less ｣ｯｾｵｳｩｮｧＮ Bl49 also
the "approval" authorities to rule whether or a vent shall be used.
p.21 (b) A liances re uirin ､ｲ｡ｾ hoods. NBC
and B149 {1.5.3 are essentially the same except
ｾｯｲ uappliances approved ｾｯｲ use without a ､ｲ｡ｾｴ
hood" in B149. B149 gives suggested dimensions
in Appendix A and installation requirements in 1.5.4 while NBC requires dimensions, installation and position to be "in accordance with good
engineering and commercial practicert•
p.22 para 2, in NBC is more ｳｰ･｣ｩｾｩ｣ than its
counterpart clause 1.5.7.6 in B149. para 3.
B149 contains nothing on tests ｯｾ chimneys etc.
but reqUires examination (1.5.6.1) ｢･ｾｯｲ･ use,
which NBC does not include. NBC does require
chimneys to be IIcleaned and ｬ･ｾｴ smooth" (last
para p.22). B139, clause 4.1.2, ｲ･ｾ･ｲｳ to
examination also.
p.22 NBC gives chimney constructicn details in (a), (b) and (c) which are not in B149 except
as type A vents 1.5.7.1 B139 (4.1.1) ｲ･ｾ･ｲｳ to
NBC for construction details.
(c) p.23, para 2, required cleanout opening at
chimney base with tight ｾｩｴｴｩｮｧ metal door.
Bl49 clause 1.5.6.5 reqUires cleanout at lowest
part of ｾｬｵ･ and ｯｾ such construction that it
5
-(a) p023, requires chimneys to extend 3 feet above highest point of contact with roof and at least 2 feet higher than any ridge, mansard roof, parapet wall or roof structure within 10 feet of
ito B139 is the same and shows diagram Fig. E-2
in Appendix E. NBC 602.309.4 (a) para 2, p.24,
requires vents tacks to extend 2 feet higher than
any ridge, etco within 10 feet. NBC 6.2.3.9.3
(b) p.24 requires smokestacks to extend to at least 4 feet above any robf or part thereof
within 25 feeto In B-l"-1;his is covered under
Flues or Vents in 1.5.6.3 but requires at least 2 feet above flat roofs and 2 feet above highest part of all parapets and roof peaks within 10 feet, unless an approved method of preventing
downdraft is providedo NBC 6.2.3.9.2 (d) also
requires bracing and anchoring if chimney height above roof is more than four times the minimum
dimension. ..
I
(e) to (g). There are no eqUivalents to these in
B149 or B139.
(h) p.23, gives details of material and construc-tion of chimney liners and stipulates where they
shall start and stop. B149 1.5.6.8 and 1.5.6.9
merely states that 'unlined chimneys shall not be used unless approved by the enforcing authorities
(see NBC 6.2.3.9.2 (b) para 1) and that chimney lining materials shall be approved by the enforcing
authorities. Bl;9 has no reference to chimney
liners other than referring to NBC for construction.
Smokestacks are not referred to in B149. B139
(4.1.1) mentions in a note that smokestacks are not contemplated.
(a) p.24, para 1, lists ventstack construction materials (special flue blocks, chimney liners of fire resistant clay or concrete built into masonry wall) and forms (pipes with bell and spigot, screw
or equally gas-tight joints). ｍ｡ｴ･ｾｩ｡ｬｳ must be
non-combustible and corrosion-resistant: sheet
metal ventstacks shall be eqUivalent in struc-tural strength and durabili ty to galvanized iron or steel of thickness not less than 20 U.S. gauge. B149 covers vents by types in clauses 1.5.7.1 to 10507.5.
(a) p024, para 2, allows in existing bUildings, by special permission, a ventstack that rises more than one storey to pass through a wall if a
curved fitting is used along with straps and a
cap tee and vent capo B149 (1.5.6.10) allows an
outside vent approved by the enforcing authorities
when an inside vent is impractical. It ｰｲｯｨｩｾｩｴｳ
natural draft vents extending through an outside
wall and terminating adjacent to the outside wall,
except in the case of approved appliances having sealed combustion chambers and having all air for combustion derived from outside the space being heated and all flue gases discharged to outside.
(b) NBC specifies clearances for ventstacks
for smokestacks (602.39.3 (c» and for chimneys
(6.203.9.2 (e» from combustible construction.
B149 has no such clearance requirements. B139 refers to the NBC for recommendations concerning chimney construction and does not mention clearances specifically.
p. 24, para 1, If reference is made to the use of
type A, B, BW vents etc. as outlined in B149
1.5.7, the second part of this paragraph is super-fluous.
para 2,
p.25,
NBC prohibits the use of one flueto serve appliances on different storeys. B139
and B149 have no such restriction.
para 3, second senteI+ce, NBC permits a gas-fired appliance to be connected to a flue serving a solid or liqUid fuel fired heating appliance prOVided the gas appliance has provision for "automatically shutting off all the ?tas supply when the pilot light is extinguished' and provided the connection is at least 8 inches above the
smokepipe connecuon. B149 (1.5.6.6) contains
essentially the same regulation but only requires connections "at diff;erent levels" instead of 8
inches above the smokepipe. (In the latest
revision of B149 ｴｨｾ words "or liquid" ?re being
inserted between "sdlicftand "fuels" at the end of
the third last line). B139 Fig. E-4 shows method
- 7 - .
para 4, regarding more than one ｧ｡ｳＭｾｩｲ･､ heating appliance being served by one ｾｬｵ･ requires
protection ｯｾ each appliance by an automatic
pilot device in NBC, whereas B149 1.5.6.7 is more concerned about the type ｯｾ ｾｩｴｴｩｨｧ and the size of the common vent.
para 6, regarding cross-sectional area of ｾｬｵ･ｳ
requires "good engineering and commercial practice" and para 7, 8 and 9 specify dimensions and areas. B149 (1.5.6.2) goes ｾｵｲｴｨ･ｲ and gives heights as well, and relates flue size to appliance capacity in tables 1.7 and 1.8. (The Installation Code Committee is considering replacing tatiLes 1.7 and 1.8 with the William Wallace Co. venting tables submitted by the Metalbestos Division at the Feb. 1959 meeting in Toronto). B139 Appendix E Table E-l gives recommended dimensions based on
ｾｩｲｩｮｧ rate and in Fig. E-3 gives ideal
cross-sections for round and rectangular ｾｬｵ･ｳＮ
para 11, at bottom ｯｾ col. 1 and top of col. 2, p.25, is essentially the same as B149 1.5.6.2 except that NBC is more ｳｰ･｣ｩｾｩ｣ regarding sizing of ｲｾ｣ｴ｡ｮｧｵｬ｡ｲ ｾｬｵ･ｳＮ
para 12, gives 60 degree limit on inclined vent-stacks
(45
0 ｾｯｲ chimneys and smokestacks) whereasB149 has no such stipulation.
last para, says two or more connections to the same ｾｬｵ･ must be "so located that no horizontal plane can pass through more tban one connection". B149 1.5.6.6 is less precise fusing the words l1a t
､ｩｦｾ･ｲ･ｮｴ levels". B139 gives diagram and explanation in Fig. E-4.
(a) para 1, gives the construction materials .f'or smokepipes. No such construction pr materials are listed in B139, although 4.3.9 requires
ugood conditionn •
(a) para 2, cross-sectional area corresponds with B139 4.3.7.
(a) para 3, allows smokepipes ｯｾ small stoves, ranges and space heaters in one ｾ｡ｭｩｬｹ dwellings to pass through ceilings and floors using 4 inches
•
8-Both codes allow passage through combustible walls and partitions although NBC requires approval by the adm1nistrative official and B139 (4.3.3)
sets a limit of 10000F and provided (in both codes) that certain protective measures are carried out. NBC requires 4 inches of solid masonry with an air space or alternatively a metal thimble of two rings with 2 inch air space, while B139 requires
(4.3.5) a metal thimble 12 inches larger than the pipe,or thimble built in brickwork extending 8 inches beyond the thimble, or a straight ｯｰ･ｾｩｮｧ
large enough to give proper clearance which
opening may be filled with non-combustible insulating material.
(a) last para, p.26, regarding length and supporting of smokepipe has as its counterpart in B139
clauses 4.3.10 to 4.3.14. Wording is qUite different. (b) is similar to B139 (4.3.6) although the latter requires cementing of flue pipe or thimble whereas the former requires the connections to be air and gas tight.
(c) gives a clearance of 18 inches which agrees with B139 Table 10 last column except for boilers and other appliances in installation class 4. Clearances with specified forms of protection NBC table 6.7 and B139 table B-1 agree except where ｬｾｬｴ asbestos-cement covering is used (NBC, 9 inches; B139, 18 inches). B139 lists three additional forms (f) (h) and (i) in Table B-1 which NBC does not list. B139 also gives
diagram Fig. B-1 which fixes the width of the protection to give C equal to A. Dimension B is incorrectly shown. (This will likely be corrected in subsequent issues of B139).
(d) p.26, the wording of the first part of this clause is probably intended to be "smokepipes serving two or more gas-fired ｨ･｡ｾｩｮｧ appliances --- may be connected to a common smoke-pipe ••••••• etc". This compares with B149
(1.5.6.7) but the latter is more concise.
(a) p.26, NBC restricts vent connectors ｾｯ gas-fired appliances which cannot readily be converted t,o the use of solid or liquid fuels, and sets a limit of 550°F. for flue gas temperatures. B149 has no comparable regulation.
1
•
•
•
6.2.3.9.7 9-(b) para 1, NBC and B149 (1.5.5.1) agree on the 28
U.S.
gauge minimum, but B149 goes further in specifying heavier gauges for larger sizes and also specifies minimum gauge for aluminum. NBC lists other materials, terracotta, cement, etc. which are not in common use and therefore might not need to be mentioned specifically. The NBC requirement of low heat conductivity seems peculiar since virtually all vent connectors are of metal.(b) para 2, sentence 1, regarding cross-sectional area should read "not less than the area of the flue collar (not vent) of the heat producing
unit" B149 (1.5.5:Brincludesalso the draft hood. Sentence 2 regarding the size of vent connector specifies a minimum of 3 inches diameter or, if rectangular, smallest dimension 3 inches or more with area 12 sq. ins. or more. B149 makes no mention of sizes.
(b) para 3, sentence 1, no such reqUirements in B149. Sentence 2 - Vent connectors passing through floors,walls, partitions must be approved by the administrative official and must have 4 inches of solid masonry or a metal thimble. B149 (1.5.5.6) mentions only partitions of combustible construc-tion and requires ventilated thimbles. NBC
regulations on thimbles (sentences 3, 4
&
5 of para 3) are quite different from B149 1.5.5.7.(b) para 4, is similar to B149 1.5.5.4 and 1.5.5.5 but B149 specifies maximum length of run. B149
also specifies pitch or rise (1.5.5.2) and vertical run (1.5.5.3).
(b) last para, p.27, regarding dampers is the same as B149 except that special permission may be
granted under B149 (1.5.5.9)
{c) and B149 (1.5.6.4) are essentially the same although the wording of the latter is more ex-planatory.
(d) Clearances shall not be less than 3 inches and temperature on adjacent combustible material not in excess of 160°F. B149 (1.5.5.6) differentiates between metal vent connectors and type B vent
connectors in Table 1.5 (although these two are not defined) and gives minimum vent connector
•
6.2.3.9.1
10
-clearances for approved appliances. Maximum allowable temperature is 90° above normal rOOm temperature 0 Reduced clearances with specified protection are given in Table 106.
(e) 1'.21. The first part of this clause is
probably intended to read "Vent connectors serving two or more gas-fired heating appliances •••• may be connected to a common smokepipe 0••• etc.1t
B149 is more concise in 1.5.6.10
Alternate chimney assemblies. See comments under definition for "chimney". .Consideration
might be given to referencing published Underwriters Labs (Chicago) Standards for Factory-Built Chimneys and Gas Vents.
•
•
In considering the formulation of regulations for the 1960 edition of the National Building Code a decision will have to be made as to which items should be covered by the NBC and which items might appear in C.SoA. Standards B139 and B149. One possibility would be to cover items pertaining directly to the design of the venting ｾｹｳｴ･ｭＬ the provision of the requireq draft and capacity, in the C.S.A. Standards B139 and B149.
The NBC would then oover all aspects of construction and instal-lation pertaining direotly to fire and struotural safety. The NBC would also have to cover venting reqUirements for solid fuel fired appliances.
