Appendix A — Division A
Explanatory Material
A-1.1.1.1.(1) Application to Existing Buildings. 
(See Division B Part 11 of Book I.)
(See Division B Part 11 of Book I.)
A-1.2.1.1.(1)(a) By-law Compliance via Acceptable Solutions
By-law Compliance via Acceptable SolutionsIf a plumbing system design (e.g. material, component, assembly or system) can be
shown to meet all provisions of the applicable acceptable solutions in Division B
(e.g. it complies with the applicable provisions of a referenced standard), it is
deemed to have satisfied the objectives and functional statements linked to those
provisions and thus to have complied with that part of the By-law. In fact, if it can be determined that a design meets all the applicable acceptable solutions in Division B, there is no need to
consult the objectives and functional statements in Division A to determine its
compliance.
By-law. In fact, if it can be determined that a design meets all the applicable acceptable solutions in Division B, there is no need to
consult the objectives and functional statements in Division A to determine its
compliance.
A-1.2.1.1.(1)(b) By-law Compliance via Alternative Solutions
By-law Compliance via Alternative SolutionsWhere a design differs from the acceptable solutions in Division B, then it should
be treated as an “alternative solution.” A proponent of an alternative solution must
demonstrate that the alternative solution addresses the same issues as the
applicable acceptable solutions in Division B and their attributed objectives and
functional statements. However, because the objectives and functional statements are
entirely qualitative, demonstrating compliance with them in isolation is not
possible. Therefore, Clause 1.2.1.1.(1)(b) identifies the principle that Division B establishes the quantitative performance targets that alternative
solutions must meet. In many cases, these targets are not defined very precisely by
the acceptable solutions—certainly far less precisely than would be the case with
a
true performance code, which would have quantitative performance targets and
prescribed methods of performance measurement for all aspects of building
performance. Nevertheless, Clause 1.2.1.1.(1)(b) makes it clear that an effort must be made to demonstrate that an alternative solution will perform as well as a design that would satisfy the
applicable acceptable solutions in Division B—not “well enough” but “as well
as.”
In this sense, it is Division B that defines the boundaries between acceptable
risks and the “unacceptable” risks referred to in the statements of the
By-law's objectives, i.e. the risk remaining once the applicable acceptable solutions in Division B have been
implemented represents the residual level of risk deemed to be acceptable by the
broad base of Canadians who have taken part in the consensus process used to develop
the By-law.
By-law's objectives, i.e. the risk remaining once the applicable acceptable solutions in Division B have been
implemented represents the residual level of risk deemed to be acceptable by the
broad base of Canadians who have taken part in the consensus process used to develop
the By-law. Level of Performance
Where Division B offers a choice between several possible designs, it is
likely that these designs may not all provide exactly the same level of
performance. Among a number of possible designs satisfying acceptable solutions
in Division B, the design providing the lowest level of performance should
generally be considered to establish the minimum acceptable level of performance
to be used in evaluating alternative solutions for compliance with the
By-law.
By-law. Sometimes a single design will be used as an alternative solution to several
sets of acceptable solutions in Division B. In this case, the level of
performance required of the alternative solution should be at least equivalent
to the overall level of performance established by all the applicable sets of
acceptable solutions taken as a whole.
Each provision in Division B has been analyzed to determine to what it applies
and what it is intended to achieve. The resultant application and intent
statements clarify what undesirable results each provision seeks to preclude.
These statements are not a legal component of the By-law, but are advisory in nature, and can help By-law users establish performance targets for alternative solutions. They are published in the
electronic version of the By-law and as a separate document entitled “Supplement to the NPC 2010: Application and
Intent Statements,” which is available on-line at 
www.nationalcodes.nrc.gc.ca
.
By-law, but are advisory in nature, and can help By-law users establish performance targets for alternative solutions. They are published in the
electronic version of the By-law and as a separate document entitled “Supplement to the NPC 2010: Application and
Intent Statements,” which is available on-line at www.nationalcodes.nrc.gc.ca. Areas of Performance
A subset of the acceptable solutions in Division B may establish criteria for
particular types of designs (e.g. certain types of materials, components,
assemblies, or systems). Often such subsets of acceptable solutions are all
attributed to the same objective: Sanitation for example. In some cases, the
designs that are normally used to satisfy this subset of acceptable solutions
might also provide some benefits that could be related to some other objective:
Protection of the Building or Facility from Water and Sewage Damage for example.
However, if none of the applicable acceptable solutions are linked to Objective
OP5, Protection of the Building or Facility from Water and Sewage Damage, it is
not necessary that alternative solutions proposed to replace these acceptable
solutions provide a similar benefit related to Protection of the Building or
Facility from Water and Sewage Damage. In other words, the acceptable solutions
in Division B establish acceptable levels of performance for compliance with the
By-law only in those areas defined by the objectives and functional statements attributed to the acceptable
solutions.
By-law only in those areas defined by the objectives and functional statements attributed to the acceptable
solutions.
Applicable Acceptable Solutions
In demonstrating that an alternative solution will perform as well as a design
that would satisfy the applicable acceptable solutions in Division B, its
evaluation should not be limited to comparison with the acceptable solutions to
which an alternative is proposed. It is possible that acceptable solutions
elsewhere in the By-law also apply. The proposed alternative solution may be shown to perform as well as the most apparent acceptable solution, which it is
replacing, but may not perform as well as other relevant acceptable solutions.
For example, an innovative piping material may perform adequately in a drainage
system but may not meet combustibility requirements elsewhere in the By-law. All applicable acceptable solutions should be taken into consideration in
demonstrating the compliance of an alternative solution.
By-law also apply. The proposed alternative solution may be shown to perform as well as the most apparent acceptable solution, which it is
replacing, but may not perform as well as other relevant acceptable solutions.
For example, an innovative piping material may perform adequately in a drainage
system but may not meet combustibility requirements elsewhere in the By-law. All applicable acceptable solutions should be taken into consideration in
demonstrating the compliance of an alternative solution.
A-1.4.1.2.(1) Defined Terms
Auxiliary Water Supply
The auxiliary water supply may include water from a secondary potable water
supply or from any natural source, such as a well, lake, spring, stream or
harbour. It may also include waste water (but not sanitary drainage) from
industrial processes, such as cooling towers, or from storm retention ponds.
These sources may be polluted or contaminated and constitute an unacceptable
water source over which the primary water purveyor does not have sanitary
control. It is generally accepted that there are two categories of auxiliary
water supply:
- any public potable water supply over which the primary water purveyor does not have sanitary control, or
- any private water supply, other than the primary potable water supply, that is on or available to the premises.
Harvested or recovered rainwater commonly refers to a type of auxiliary water supply that is collected from external surfaces of
buildings or other hard-surfaced areas not exposed to vehicular or pedestrian
traffic.Auxiliary water supply that meets the definition of potable water can be used to supply potable water systems. Auxiliary water
supply that doesn’t meet the definition of potable water can be used to
supply non-potable water systems.Class 3 Fire Sprinkler/Standpipe Systems
In Class 3 fire sprinkler/standpipe systems, water is supplied to the storage
facilities from the public water supply and is maintained in potable condition.
Class 3 fire sprinkler/standpipe systems resemble Class 1 fire
sprinkler/standpipe systems in all other respects.
Clear-Water Waste
Examples of clear-water waste are the waste waters discharged from a drinking
fountain, cooling jacket, air conditioner or relief valve outlet.
Designated Flood Plain The Burrard Inlet, English Bay, False Creek and Fraser River flood plains are
illustrated on Diagram A1 and the wave effect zones are illustrated on Diagram
A2. See Figure A-1.4.1.2.(1)-A for Diagram A1 and Figure A-1.4.1.2.(1)-B for Diagram A2.
The Still Creek flood plain is illustrated on Diagram B. See Figure A-1.4.1.2.(1)-C for Diagram B.
Emergency Floor Drains
There are two types of floor drains. One is an emergency floor drain installed
to avoid flooding in a building from any pipe or fixture failure. The other
encompasses floor drains installed to receive discharge from specific pieces of
equipment; this type is defined as a fixture.
Flood Construction Level Requirements The Burrard Inlet, English Bay, False Creek and Fraser River flood plains are
illustrated on Diagram A1 and the wave effect zones are illustrated on Diagram
A2. See Figure A-1.4.1.2.(1)-A for Diagram A1 and Figure A-1.4.1.2.(1)-B for Diagram A2.
The Still Creek flood construction levels are illustrated on Diagram B.
See Figure A-1.4.1.2.(1)-C for Diagram B.
Heritage Building
Heritage buildings are buildings that are legally recognized by the Province
or City as having historic, architectural or cultural value for the Province or
their communities. To qualify as a heritage building under the Vancouver
Building By-law, a building must be:
- protected as heritage property by the Province under the Heritage Conservation Act or the Park Act;
- subject to a heritage designation bylaw pursuant to the Vancouver Charter;
- listed in the Provincial heritage register or in an inventory of heritage buildings maintained for this purpose under section 20(1)(h) of the Heritage Conservation Act.
Despite this definition of Heritage Buildings, the Chief Building Official may
accept a lesser standard.
Illustrations for Defined Terms
Figure A-1.4.1.2.(1)-A
Diagram A1: Burrard Inlet, English Bay, False Creek and
Fraser River Flood Plains
Figure A-1.4.1.2.(1)-B
Diagram A2: Burrard Inlet,
English Bay, False Creek and Fraser River Flood Plain Wave Effect
Zone
Figure A-1.4.1.2.(1)-C
Diagram B: Still Creek Flood
PLain and Flood Construction Levels
Figure A-1.4.1.2.(1)-D
Backflow preventer
Figure A-1.4.1.2.(1)-E
Back-siphonage
Notes to Figure A-1.4.1.2.(1)-E:
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Figure A-1.4.1.2.(1)-E shows a situation that is fairly common in old buildings. If the bathtub is
filled to a level above the faucet outlet, or if the flush valve of the
water closet is faulty, and if the faucet at the sink or lavatory on the
lower floor is opened, water can be drawn (siphoned) from the bathtub or
the water closet into the water system when the pressure in the water
system is low or the water supply has been shut off.
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Back-siphonage can be prevented in the above situations by
providing an air gap or a back-siphonage preventer (see Subsection 2.6.2. of Division B).
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Figure A-1.4.1.2.(1)-F
Back-siphonage preventer
Figure A-1.4.1.2.(1)-G
Branch vent
Notes to Figure A-1.4.1.2.(1)-G:
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See also the definitions of header and drainage system in
Article 1.4.1.2. |
Figure A-1.4.1.2.(1)-H
Continuous vent
Figure A-1.4.1.2.(1)-I
Drainage System
Figure A-1.4.1.2.(1)-J
Venting System
Figure A-1.4.1.2.(1)-K
Fixture Outlet Pipe and Trap Arm
Figure A-1.4.1.2.(1)-L
Vent Header
Notes to Figure A-1.4.1.2.(1)-L:
Figure A-1.4.1.2.(1)-M
Nominally Horizontal and Nominally Vertical
Figure A-1.4.1.2.(1)-N
Offset
Figure A-1.4.1.2.(1)-O
Plumbing System
A-1.5.1.1.(1) Application of Referenced Documents
Documents referenced in the NPC may contain provisions covering a wide range of
issues, including issues that are unrelated to the objectives and functional
statements stated in Parts 2 and 3 of Division A respectively; e.g. conservation of
water resources. Sentence 1.5.1.1.(1) is intended to make it clear that, whereas referencing a document in the NPC generally has the effect of
making the provisions of that document part of the By-law, provisions that are unrelated to plumbing systems or to the objectives and functional statements attributed to the provisions
in Division B where the document is referenced are excluded.
By-law, provisions that are unrelated to plumbing systems or to the objectives and functional statements attributed to the provisions
in Division B where the document is referenced are excluded.
Furthermore, many documents referenced in the NPC contain references to other
documents, which may also, in turn, refer to other documents. These secondary and
tertiary referenced documents may contain provisions that are unrelated to plumbing
systems or to the objectives and functional statements of the NPC: such
provisions—no matter how far down the chain of references they occur—are not
included in the intent of Sentence 1.5.1.1.(1) of Division A.
A-2.2.1.1.(1) Objectives
Listing of objectives
Any gaps in the numbering sequence of the objectives are due to the fact that
there is a master list of objectives covering the three principal National Code
Documents—the National Building Code, the National Fire Code and the National
Plumbing Code—but not all objectives are pertinent to all Codes.
The building or facility
Where the term “the building or facility” is used in the wording of the
objectives, it refers to the building or facility for which compliance with the
National Plumbing Code is being assessed.
A-3.2.1.1.(1) Functional Statements
Listing of functional statements
The numbered functional statements are grouped according to functions that deal
with closely related subjects. For example, the first group deals with fire risks,
the second group deals with the structural properties of piping materials, etc.
There may be gaps in the numbering sequence for the following reasons:
- Each group has unused numbers which allows for the possible future creation of additional functional statements within any one group.
- There is a master list of functional statements covering the three principal National Code Documents—the National Building Code, the National Fire Code and the National Plumbing Code—but not all functional statements are pertinent to all Codes.