Publisher’s version / Version de l'éditeur:
Canadian Consulting Engineer, 42, May 3, pp. 39-40, 42, 2001-05-01
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.
NRC Publications Archive
Archives des publications du CNRC
This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur.
Access and use of this website and the material on it are subject to the Terms and Conditions set forth at
Objectively speaking : the aim of objective-based construction codes is to help users understand their provisions and more easily evaluate equivalencies
Archer, J. W.; Gallagher, J. F.
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=3ab92532-a0fa-46a3-9de1-e9d15e5ea347 https://publications-cnrc.canada.ca/fra/voir/objet/?id=3ab92532-a0fa-46a3-9de1-e9d15e5ea347
based construction codes is to help users
understand their provisions and more easily
evaluate equivalencies
Archer, J.W.; Gallagher, J.F.
A version of this paper is published in / Une version de ce document se trouve dans : Canadian Consulting Engineer, v. 42, no. 3, May 2001, pp. 39-40, 42
www.nrc.ca/irc/ircpubs
NRCC-44985
22 March, 2001
Page 1 of 7
Objectively speaking : the aim of objective-based construction
codes is to help users understand their provisions and more
easily evaluate equivalencies
____________________________________________
by John W. Archer and Jim Gallagher
The National Building Code of Canada is sixty years old this year. In 1941, a group led by engineers and scientists at the National Research Council published the first edition. It quickly became a major foundation of the federal government’s war-time construction effort. Afterwards, the National Research Council continued to provide engineering and research support for its development and today it is the basis for all of the provincial and territorial building codes in Canada. It has reached a level of maturity that gives it world-wide respect as a model for regulation.
However, reaching the age of maturity does not mean that retirement is near. In fact, the National Building Code, and its companions the National Fire Code and the National Plumbing Code, are picking up a new head of steam, fueled by a series of changes that will make them more progressive, flexible, supportive of innovation, and abreast of international regulatory and economic trends.
The new focus of the so-called national model codes is the result of an important strategic planning initiative by its governance body, the Canadian Commission on Building and Fire Codes. A number of new economic realities – increasing globalization, free trade, demands for better quality and performance, and a major shift from new construction to rehabilitation – had identified the need to make the codes more dynamic and responsive, better able to facilitate innovation. At the same time, the Commission recognized that it had to deal with criticism that the maturing codes had, along the way, become difficult to understand and apply and had expanded their scope into areas where there may not be national consensus.
All of this led the Commission to make the pivotal decision to retool the National Building Code, the National Fire Code and the National Plumbing Code in a substantial way, one that would permit an evolutionary approach to modernization. In this new approach, called “objective-based codes,” the value and “knowledge equity” in the current codes would be preserved, but mechanisms for more effective and rapid evolution would be put in place.
The widespread support for these changes from the provinces and territories – which have the constitutional responsibility for construction regulation – speaks well of the federal-provincial cooperation that has marked the development and use of the model codes. And the level of cooperation and collaboration will be increasing. A new code development process supported by provincial and territorial deputy ministers in 2000 signals greater coordination in the development and review of the national model codes. The adoption of the National Building Code and its fire and plumbing companions over the years reflects the belief of those visionary code writers of 1941 that there are benefits
to Canada’s economy in general, and to the construction industry in particular, from uniformity in code requirements. These benefits include:
- a uniform level of health and safety for all Canadians;
- one large domestic market with common requirements, facilitating the movement of goods and services across provincial boundaries;
- a minimizing of duplication of effort, allowing for cost sharing of technical development;
- the promotion of cost-effective, technically progressive solutions; - credibility for Canadian technologies in international markets;
- a reduction in design and compliance verification costs for those working in multiple jurisdictions.
Created with such benefits in mind, the national model codes have, to a great extent, been successful in achieving them. In its decision to restructure the three codes into an
objective-based format, the Commission is trying to make a good product better, by making the codes easier to use, more responsive to the market place, and more open to technological advances.
The first step in the restructuring was to carry out an exhaustive review of all the
provisions in the three codes. The specific intent of each provision and the overall code objective(s) (health, safety, accessibility) to which it is related were identified. As well, detailed application statements were developed to clarify just how the provision is applied when using the code. All of this analysis is stored in a large “Intents Database” that will be made available to code users.
The review and analysis produced some surprises. For example, although the National Building Code is widely acknowledged to be concerned with the three basic objectives of health, safety (fire and structural) and accessibility, it was found that numerous other objectives had seemingly found their way into the document over the years. In fact, code committees identified 14 such additional objectives, such as the one of convenience. During 2001 the Canadian Commission on Building and Fire Codes, in partnership with the provinces and territories, is consulting with construction practitioners and other code users to confirm that its analysis of the objectives of the codes is correct and to seek comment on the proposed objective-based structure.
Structure of the objective-based codes
Although the exact structure of the new codes will not be decided until after a national consultation in 2002, there seems to be good initial support for separating each of the new objective-based codes into two major divisions.
Division A will contain the statements of the codes’ Objectives and Functional
Requirements, as well as information on how to use the codes. This part will use quite general language because it will address the reasons why the design and construction of buildings are regulated. Because Division A will be at such a “high” level, it is expected
22 March, 2001
Page 3 of 7
that it will be revised only when fundamental changes reflecting an expansion or contraction of the objectives of a particular code are deemed necessary.
Division B will be the part intended for everyday use. It will identify how the building should be designed and constructed to meet the Objectives and Functional Requirements found in Division A. In the case of the National Building Code, Division B will
essentially contain the provisions found in the current (1995) version. These prescriptive provisions and performance criteria (where they exist) will constitute what are referred to as the “Acceptable Solutions” to the Objectives and Functional Requirements found in Division A. Division B will be revised on a regular schedule, as is the case with the current codes.
Definitions of Terms
Prescriptive provisions – these specify by name the materials or construction that has to be provided.
Example: An exit stair shall be provided with an exhaust fan with a capacity of 60 litres per second.
Performance provisions – these specify conditions that are to be provided but don’t specify how.
Example: An exit stair shall not contain more than 1% by volume of
contaminated air.
Objectives – these state in broad terms what the code is intended to achieve (e.g., health, safety, accessibility).
Sub-Objectives – these focus on aspects of the overall objective that narrow its scope. Functional Requirements – these describe in greater detail the conditions to be
achieved within the scope of the Sub-Objectives.
Acceptable Solutions – these are the minimum design and construction features that meet the Objectives and Functional Requirements.
Intents – these describe in plain language the reasons underlying the Acceptable Solutions. They will not be part of the code, but will be available as reference material similar to current users’ guides.
It is envisioned that Division A will have a logical structure of increasingly specific Objectives, Sub-Objectives, and Sub-Sub-Objectives. Each Objective and Sub-Objective will be linked to Functional Requirements that will explain what the Objective intends to achieve in qualitative terms.
Relation between an Objective and Sub-Objectives, Division A
ObjectiveSafety: An objective of this Code is to reduce the probability that a person in or adjacent to the building will be exposed
Sub-Objective
Fire Safety: An objective of this Code is to reduce the probability that a person in or adjacent to the building will be exposed to
to an unacceptable safety hazard as result of the design and construction of the building.
an unacceptable fire hazard as a result of the design and construction of the building. Structural Safety: An objective of this Code is to reduce the probability that a person in or adjacent to the building will be exposed to an unacceptable hazard due to failure of the structure as a result of the design and construction of the building. Safety-in-Use: An objective of this Code is to reduce the probability that a person in or adjacent to the building will be exposed to an unacceptable risk of injury from hazards as a result of the design and construction of the building.
Division B, on the other hand, will follow the “discipline-based” structure employed in the current versions of the codes. This retention of the current structure was requested by designers and other practitioners because they are familiar with it and because it reflects the way the industry works. The Table of Contents for Division B is proposed to look like this:
National Building Code
Division B Acceptable Solutions Part 1 Administration
Part 2 Fire Protection Part 3 Access and Use Part 4 Structural Design
Part 5 Environmental Separation
Part 6 Heating, Ventilating and Air-Conditioning Part 7 Plumbing Services
Part 8 Reserved
Part 9 Housing and Small Buildings
The linkages between the two Divisions will be very clear, so that a user wishing to propose an innovative alternative to one of the Acceptable Solutions in Division B can quickly find in Division A the appropriate Objectives and Functional Requirements that must be satisfied.
How Will an Objective-Based Code Work?
It is important to note that the current National Building Code, National Fire Code and National Plumbing Code all permit equivalencies. In fact, it is clearly stated in the General Requirements that the provisions of these codes are not intended to limit the appropriate use of materials, appliances, systems, equipment, methods of design or
22 March, 2001
Page 5 of 7
construction procedures not specifically prescribed. When something new is proposed, however, it must be demonstrated that it provides an equivalent level of performance. The problem in proposing equivalencies with the current versions of the codes lies in trying to understand or determine what performance is actually to be provided. The new objective-based codes will go a long way toward facilitating this understanding and hence facilitating innovative solutions. Let’s look at an example from the National Fire Code (NFC).
Section 4.3 of the NFC establishes requirements for “containment” spaces around storage tanks for flammable and combustible liquids. This is usually a bermed area around the tank such that the volume of the space between the tank and the berm and between the ground and the top of the berm is equal to 110% of the volume of the tank. This is to restrict the flow of any liquid that leaks from the tank or of fire fighting water used in quenching a fire in the tank from reach waterways, sewer systems or potable water sources.
Sentence 4.3.7.9.(1) precludes the use of this containment space for storage purposes. Suppose the proprietor of a tank farm proposes to store next to a storage tank empty drums used in distributing the liquid stored in the tank. By studying the links to Division A found beside this sentence in Division B, he determines that this requirement is related to the sub-objectives Fire Safety, Protection of the Building or Facility from Fire and
Containment of Hazardous Substances. He finds nothing in this that would immediately
preclude his plan.
From the Intents Database, he finds that there are three intent statements for Sentence 4.3.7.9 (1):
1. “To reduce the probability of reduced holding capacity or unavailability of the containment in an emergency, which could lead to the escape of liquid outside of the spill containment, which could lead to the ignition of vapour from a nearby ignition source, causing harm to persons.”
He therefore proposes to increase the volume of the containment space beyond the minimum required by an amount equal to the volume needed for storage of the drums. 2. “To reduce the probability of creating a fire hazard near the storage tank, which
could lead to a fire exposure to the tank, which could lead to the escape and spread of liquid, which could lead to the ignition of vapour from a nearby ignition source, causing harm to persons.”
Since the drums are made of steel and are empty while stored there, this intent should not hinder his proposal.
3. “To reduce the probability of delays or ineffectiveness in conducting fire-fighting or spill-control operations, which could lead to the spread of fire beyond its point of origin, causing harm to persons.”
This could be the issue on which the proposal fails. But perhaps an agreement could be negotiated with the fire department such that the drums would be stored in a part of the containment space where they would least impair fire-fighting and spill-control
Where do the codes go from here?
The new objective-based national model codes will make available to the construction industry much more information to both aid in understanding code provisions and in evaluating equivalencies. Time and resources will not be wasted proposing something that will not be acceptable. What is also important about objective-based codes is that the construction practitioner and the official who assesses code conformance have a better common understanding of the issues, thus promoting informed discussion.
The development of the three new objective-based national model codes is proceeding, with current plans to publish at the end of 2003. During 2001 the provinces and territories are working with the Canadian Commission on Building and Fire Codes to complete a public review of the objectives and the proposed structure of the new codes. Planned for 2002 is the actual conversion of the three codes to the objective-based structure. These draft documents will then be released for public review and comment. The objective-based approach is an innovative and uniquely Canadian approach to
modernizing the national model codes. It is one that minimizes disruption to construction practitioners while at the same time opening the codes to the realities and opportunities of the modern global economy and standards harmonization internationally. Other countries are keenly interested in the progress we are making.
Note: a detailed discussion of the objectives of the three national model codes as well as a range of background documents on the process that is being followed in developing objective-based codes can be found on the web site www.ccbfc.org. There, as well, under Appendix B, the reader can find an objective-based safety-related example from the National Building Code.
_______________________________
John W. Archer is with the Canadian Codes Centre of the National Research Council’s Institute for Research in Construction (IRC) and is Secretary of the Canadian
Commission on Building and Fire Codes. Jim Gallagher is Manager of Publication Services at IRC.
Note to readers: Quite different fire-safety objectives and issues are addressed in the National Building Code and the National Fire Code. The relationship between the two codes is explained in an identical introductory page contained in the two documents, which reads more or less as follows:
The National Building Code establishes a satisfactory standard of fire safety for the design and construction of new buildings, including fire safety features, the
reconstruction of buildings, including extensions, alterations or changes in occupancy and upgrading of buildings to remove an unacceptable fire hazard.
The National Fire Code establishes standards for fire prevention, firefighting and life safety in buildings in use, including standards for the conduct of activities causing fire
22 March, 2001
Page 7 of 7
hazards, maintenance of fire safety equipment and egress facilities, standards for portable extinguishers, limitations on building contents and the establishment of fire safety plans, including the organization of supervisory staff for emergency purposes. The NFC also establishes the standard for prevention, containment and suppression of fires originating outside buildings, which may present a hazard to the community, and addresses the storage and handling of dangerous goods, and flammable and combustible liquids.
