Canadian Consulting Engineer

Objectively speaking

The National Building Code of Canada is 60 years old this year. However, reaching the age of maturity does not mean that retirement is near. In fact, the National Building Code, and its companions the...

May 1, 2001   By John W. Archer and Jim Gallagher, NRC/IRC

The National Building Code of Canada is 60 years old this year. 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 and flexible, and help them keep abreast of international regulations and economic trends.

The new focus of the so-called national model codes is the result of a strategic planning initiative by its governing body, the Canadian Commission on Building and Fire Codes. A number of economic realities — increasing globalization, free trade, demands for better quality and performance, and a major shift from new construction to rehabilitation — had created the need to make the codes more dynamic and responsive, better able to facilitate innovation. The Commission also 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, using what are 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 first step in the restructuring was to carry out an exhaustive review of all 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.

This year, the Commission, 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.

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. Current plans are to publish at the end of 2003.

New structure

Although the exact structure of the new codes will not be decided until after a national consultation in 2002, there was initial support for separating each of the new objective-based codes into two major divisions.

Division A will give the codes’ Objectives and Functional Requirements, as well as information on how to use them. 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 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.

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.

Division B, on the other hand, will follow the “discipline-based” structure used in the current versions of the codes (Part 1, Administration; Part 2, Fire Protection; Part 3, Access and Use; Part 4, Structural Design, etc.) 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 links 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.

Codes in action

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 are not intended to limit the appropriate use of materials, appliances, systems, equipment, methods of design or 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. Take 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 containment space 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. The idea 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 reaching 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 operations, e.g. well away from the tank’s valves.

Where now?

The new objective-based national model codes will make available to the construction industry much more information to aid users both to understand code provisions and to evaluate 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 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 it opens 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.

A detailed discussion of the objectives of the three national model codes as well as a range of background documents can be found on the web site www.ccbfc.org.

John W. Archer is with the Canadian Codes Centre of the NRC’s Institute for Research in Construction (IRC) in Ottawa and is Secretary of the Canadian Commission on Building and Fire Codes. Jim Gallagher is manager of publication services at IRC.


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