Code Change Request

Title

Part 3 – Single egress for multi-unit residential buildings up to 6 storeys

Description

This request for change proposes additional sentences under NBC Div.B Section 3.4.2.1 to introduce single exit multi-unit residential buildings of up to six storeys, requiring additional life safety measures and placing limits on the occupant load and number of dwelling units per storey served by the single exit.

Proponent

Conrad Speckert
LGA Architectural Partners

David Hine
David Hine Engineering Inc.

Submitted

2022-04-18

Code Reference(s)

NBC Div. B – 3.4.2.1

Standing Committee(s)

Use and Egress, Fire Protection

Related CCR(s)

Part 9 – Single egress for multi-unit residential buildings up to 3 storeys

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What is the problem?

The requirement for two means of egress in multi-unit residential buildings exceeding two storeys may be an outdated condition of pre-modern fire safety practices in combustible construction. The National Building Code of Canada is inconsistent with (and does not allow for the same design flexibility as) building codes in other jurisdictions and fails to recognize that a second egress may be unnecessary for mid-rise housing typologies where other life safety measures are provided.

By prohibiting single egress designs at this scale, the National Building Code limits the feasibility of buildings that are between low-rise single-family homes and high-rise apartment buildings. Making it difficult to build mid-rise housing prevents urban areas from developing more sustainable growth and increasing the balanced supply of housing with an expanded range of affordable options.

This code change request recognizes that the requirement for two means of egress is appropriate for larger buildings and non-residential occupancies. However, requiring a second egress is a prohibitive burden for smaller multi-unit residential projects, whereas one exit is permitted in many other jurisdictions.

This code change request falls within several of the CCBFC’s strategic technical and policy priorities as a select fire and life safety topic and as a targeted topic. Accessibility is also addressed in terms of egressibility, the proposed life safety measures (particularly pressurization and better closures) improve the protection and fire safety for disabled occupants remaining in their suite during an emergency. Single egress also indirectly addresses the priorities of climate change mitigation and adaptation, and energy-efficiency, given the improved building form factor, design flexibility for passive ventilation and daylighting, and the sustainable urban development benefit of single stair buildings.

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Requested change/addition: What is the proposed solution and how does it address the problem?

Part 3 of the National Building Code should allow for a single means of egress in multi-unit residential buildings of up to six storeys above grade. See proposed life safety measures below and code wording on next page. A related CCR will be submitted for Part 9 to allow for a single means of egress in multi-unit residential buildings up to three storeys above grade.

The proposed code change includes reasonable limitations and additional life safety measures based on the acceptable solutions in the NBC, a review of building codes in other jurisdictions, as well as the attached reference literature and studies of fire safety in residential buildings:

• a total occupant load of 60 people on any storey served by the single exit, similar to 3.4.1.2.(2)

• no more than 4 dwelling units per storey, based on Seattle SBC 2018, 1006.3.3.7 Single Exits

• a maximum floor area of 150m2 per dwelling unit, based on Table 3.4.2.1.-B

• Note: sprinklering is not a proposed measure for the Part 3 CCR, given the code already requires such buildings to be sprinklered throughout (NFPA 13-R up to 4 storeys, NFPA-13 exceeding 4 storeys, as required by 3.2.5.12.)

• requiring positive pressurization of the exit stair, based on the requirement for smoke control measures in high-rise buildings above 18m in building height (3.2.6.2. Limits to Smoke Movement and 3.2.6.6. Venting to Aid Firefighting) and based on the pressurization requirements of the Seattle SBC 2018, 1006.3.3.7.

• increased minimum fire-protection rating of dwelling unit entrance door closures from a 20 min rating to 45 min rating, similar to the closure ratings required by several European jurisdictions

• requiring a fire alarm system without exception, and requiring automatic monitoring of the fire alarm system in conformance with 3.2.4.7. Signals to Fire Department.

Additional life safety measures that may be appropriate to add:

• requiring sprinklering of balconies (based on Calder and Senez’s 2016 study of “The Key Modes of Fire Spread in Wood-Framed Apartment Buildings, see attachments).
  

2025 National Building Code of Canada, Volume 1, Division B, Part 3
3.4.2. Number and Location of Exits from Floor Areas
3.4.2.1 Minimum Number of Exits

1) Except as permitted by Sentences (2) to (5), every floor area intended for occupancy shall be served by at least 2 exits.

2) A floor area in a building not more than 2 storeys in building height, is permitted to be served by one exit provided the total occupant load served by the exit is not more than 60, and

a) in a floor area that is not sprinklered throughout, the floor area and the travel distance are not more than the values in Table 3.4.2.1.-A, or
b) in a floor area that is sprinklered throughout
        i) the travel distance is not more than 25 m, and
        ii) the floor area is not more than the value in Table 3.4.2.1.-B.

3) Except as permitted by Sentence (4), if Sentence (2) permits a single exit from a floor area classified as Group B or Group C occupancy, the exit shall be an exterior doorway not more than 1.5 m above adjacent ground level.

4) The requirements of Sentences (1) and (2) are permitted to be waived for dwelling units that have an access to exit conforming to Sentences 3.3.4.4.(1) to (4).

5) A floor area classified as Group C occupancy in a building not more than 6 storeys in building height is permitted to be served by a single exit provided the total occupant load on any storey served by the exit is not more than 60, and

a) there shall be no more than four dwelling units on any storey served by the exit and the floor area of each dwelling unit does not exceed 150m2,

b) the building is sprinklered throughout,

c) unless an exterior stairway is provided, an interior stairway including any related exit passageway or public corridor shall be pressurized and designed in accordance with Article 3.2.6.2 to limit the danger to occupants and firefighters from exposure to smoke in a building fire,

d) openings in required fire separations shall be protected with a closure with a fire-protection rating of not less than 45 min and shall be installed in conformance with Chapters 2 to 14 of NFPA 80 “Standard for Fire Doors and Other Opening Protectives”,

e) a fire alarm system is provided without exception (See 3.2.4.1. Determination of Requirement for a Fire Alarm System), and the fire alarm system is designed to notify the fire department that an alarm signal has been initiated (See 3.2.4.7. Signals to Fire Department),

f) the floor area classified as Group C occupancy served by a single exit is not intended for use as a retirement home.

6) Exits are not required directly from rooftop enclosures that are provided with access to exits in conformance with Sentences 3.3.1.3.(5) and (6).

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Objective(s): Which of the stated objectives and functional statements of the Code will the proposed solution assist in achieving?

The Functional Statement and Objective attributions to existing sentences may not have to be changed. The attributions to the new Article being introduced may be made up of the following selection, which is consistent with the code provisions the CCR complements:

2015 NBC Div. A Part 2 - Objective Statements

OS1 - Fire Safety
An objective of this Code is to limit the probability that, as a result of the design or construction of the building, a person in or adjacent to the building will be exposed to an unacceptable risk of injury due to fire. The risks of injury due to fire addressed in this Code are those caused by—
OS1.2 - fire or explosion impacting areas beyond its point of origin
OS1.5 - persons being delayed in or impeded from moving to a safe place during a fire emergency

OS3 - Safety in Use
An objective of this Code is to limit the probability that, as a result of the design or construction of the building, a person in or adjacent to the building will be exposed to an unacceptable risk of injury due to hazards. The risks of injury due to hazards addressed in this Code are those caused by—
OS3.7 - persons being delayed in or impeded from moving to a safe place during an emergency


2015 NBC Div. A Part 3 - Functional Statements

F02     To limit the severity and effects of fire or explosions.
F03     To retard the effects of fire on areas beyond its point of origin.
F05     To retard the effects of fire on emergency egress facilities.
F06     To retard the effects of fire on facilities for notification, suppression and emergency response.
F10     To facilitate the timely movement of persons to a safe place in an emergency.
F11     To notify persons, in a timely manner, of the need to take action in an emergency.
F12     To facilitate emergency response.
F13     To notify emergency responders, in a timely manner, of the need to take action in an emergency.

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Impact Analysis: What are the cost/benefit implications?

The benefits in efficiency, cost and improved livability for a single egress building significantly outweigh the cost of the additional life safety measures. The proposed code change offers the measurable benefit of increased floor area efficiency and reduced hard construction costs for mid-rise housing types, as well as making such buildings feasible on smaller properties.

The proposed code change also has additional benefits for the environmental, spatial, and social quality of multi-unit residential buildings, such benefits include:

• making it easier for dwelling units to receive natural daylight from both sides as “through units”,

• allowing for cross-ventilated dwelling units rather than the deep, single-orientation layouts typical of double-loaded corridor buildings requiring two means of egress,

• balancing the exposure of each dwelling unit to urban and traffic noise, such that bedrooms can be placed on the quiet side and living areas along the street facing side of the building,

• making it easier to design larger, family-oriented dwelling units with three to four bedrooms, and

• improving the sense of community and social interaction in an apartment building by decreasing the number of dwelling units sharing an exit.

The proposed code change does not result in additional costs compared to buildings adhering to the existing acceptable solutions requirement for two means of egress. The proposed code change enables the alternative of a single stair design, with limitations on the building size and requirements for additional life safety measures to compensate for providing one exit. This additional design flexibility may be cost neutral or, in some cases, lead to cost savings. It may also bring buildings back into feasibility on smaller sites where the lot size does not accommodate a design complying with the second egress requirement.

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What are the enforcement implications?

The proposed code change can be enforced within the current enforcement framework of design review and permit approvals, as well as the administrative requirements for evacuation plans.

“Codes are continuously evolving to accommodate new technologies, materials, construction practices, research, social policy, and the changing needs of Canadian society. Globalization and free trade, for example, have led to the harmonization of some North American standards and increased use of international standards.

Development of code content is a consensus-based process that relies on the voluntary contributions of standing committee and task group members, and the public. A common process—from the initial proposing and consideration of code change requests to the publication of approved changes—is followed for all codes. An important feature of the code development and maintenance process is the extent of public involvement. Canada's code-writing process has one of the most extensive public review procedures in the world.”

1. Submission

Code change requests can be submitted to the CCBFC by regulatory officials, design and safety professionals, manufacturers and suppliers, contractors, building managers or owners, consumers, and other public and private sector stakeholders—in fact, by anyone with an interest in the codes.CCBFC standing committee members and NRC-IRC staff may also propose changes.

2. Work Plan

Each code change request is reviewed by the appropriate standing committee. After this initial review the standing committee determines if it wishes to work on it and to include it in its work plan for CCBFC approval and priority setting. Work plan approval and priority setting by the CCBFC ensures that code development work focuses on issues of importance to the provinces and territories as well as stakeholders.

3. Review
Once authorized by the CCBFC the appropriate standing committee undertakes a detailed review of the code change request. If the proposed change is complex and requires significant analysis, a task group may be established to study it and make recommendations. When a change has implications for a part of a code that is the responsibility of other committees, all affected committees review the change. For example, a proposed change to NBC Part 9, Housing and Small Buildings, may need to be reviewed by the committees responsible for Parts 3, 4, or 6, and may also lead to a corresponding change in one of those parts. A standing committee may reject a proposal, amend the wording, defer it pending receipt of more information or research, or approve the proposed change.

4. Pre-public Review

The provinces and territories have the opportunity to review draft proposed changes. If any of them has serious policy or administrative concerns about the inclusion of a certain proposed change for public review, the proposed change can be withdrawn or deferred for further discussion prior to public review.

5. Public Review

All proposed changes approved by the standing committees are made available for public review annually, in the fall, for two months. Additional public review periods may be called, when necessary, at other times of the year. This allows those most affected by a proposed change to provide feedback and increases the range of expertise available on any subject. Provinces and territories are invited to coordinate their public review activities with the national public review periods.

The availability of the public review documents is announced in Construction Innovation (NRC-IRC's quarterly newsletter, which is posted at www.nrc-cnrc.gc.ca/eng/ibp/irc/ci/current-issue.html) and on the National Code Documents Web site at www.nationalcodes.ca. The Internet is the primary format for distribution of public review information and receipt of comments.

6. Post-public Review

Following the public review period, the standing committees review the submitted comments. A proposed change moves forward only once all comments have been taken into consideration. Some proposed changes may be deferred or withdrawn at this point. The provinces and territories then review the final version of the proposed changes from a policy perspective and identify their concerns before the changes are submitted to the CCBFC for final approval.

7. CCBFC Approval

Following review of the proposed changes by the provinces and territories, the recommended changes are submitted to the CCBFC, and then, if approved, they are published in the next edition of the codes.

8. Translation

The approved changes are translated into French. The translation is reviewed by the Technical Translation Verification Committee to ensure accuracy, enforceability and consistency within the French documents.

Suggestions for changes to the National Model Construction Code Documents are welcome from anyone at any time. However, anyone thinking of submitting a Code Change Request should bear the following points in mind.

Consideration by Code Committees
To bring about a change in one of the National Model Construction Code Documents, you must provide sufficient information to allow the Canadian Commission on Building and Fire Codes (CCBFC) and its standing committees (Code committees) to determine that your suggested change is needed and that it is technically correct. These Code committees are made up of volunteers chosen for their expertise to represent all facets of the construction industry from all regions of Canada.

Clarity
The Code committees expect proponents to make very clear what specific change they would like to see. Code Change Requests should identify the shortcomings of the existing National Model Construction Code Document, and existing Code provisions that would be affected by the change. New wording should be suggested to address these shortcomings. It is recognized that not all those interested in improving the Codes can be experts in Code writing, and NRC Construction Codes Canada staff will suggest improvements to the proposed wording, if necessary. Nevertheless, if specific wording is used, it will help to make the proponent’s intentions clear. Code Change Requests that lack clarity may be returned to the proponents for clarification, thus prolonging the time required for the Code committees to deal with the requests.

Focus on Generic/Widespread Issues
The National Model Construction Code Documents are not intended to deal with specific products or with situations that arise only rarely. Code Change Requests should therefore address generic or widespread issues. Innovative products that are not yet covered by standards or mentioned in the Codes are not necessarily excluded from use; they can be accepted by local authorities based on the compliance provisions in the Codes regarding alternative solutions (equivalents). Services, such as the NRC Canadian Construction Materials Centre (CCMC), are available to assist authorities in evaluating such innovative products. Similarly, unique situations are best dealt with by local authorities rather than swelling the Codes with requirements that are seldom applied.

Focus on Technical Issues
With few exceptions, the National Model Construction Code Documents are strictly technical in nature and do not deal with administrative issues, such as what professional qualifications are required to perform certain functions or whether certification by a particular agency of products’ compliance with standards is necessary. The provincial and territorial agencies, which adopt the National Model Construction Code Documents, have instructed the CCBFC to avoid addressing administrative issues in the Codes because to do so could create conflicts with related provincial and territorial legislation and regulations. As a result, most administrative provisions in the National Building Code (NBC), National Fire Code (NFC), National Energy Code for Buildings (NECB) and National Plumbing Code (NPC) have been grouped in Division C of these documents. Code Change Requests should therefore address technical issues, which in the NBC, NFC, NECB and NPC are typically covered in Division B of these documents.

Objectives and Functional Statements
The NBC, NFC, NECB and NPC are objective-based Codes. This means that the objectives and functional statements each Code provision attempts to address are clearly stated. It follows that an objective-based Code will only contain provisions that are related to achieving at least one of its stated objectives and functional statements.

The objectives and functional statements of the NBC, NFC, NECB and NPC have been determined by the CCBFC, in consultation with the provinces and territories. The objectives and functional statements are listed in Parts 2 and 3 of Division A of each Code. Persons submitting a Code Change Request to the NBC, NFC, NECB or NPC should ensure that the requested change is linked to at least one of the Code’s stated objectives and functional statements.

Adding a provision that cannot be linked to one of the currently stated objectives or functional statements would require adding at least one new objective or functional statement. Although this is not out of the question, the CCBFC would consider such an expansion of the scope of the Code in question only after consultation with the provinces and territories.

Supporting Documentation
Code Change Requests should be accompanied by enough documentation to make the case that a change is needed, and that the requested change is the right change. This documentation can include research and testing results, statistics, case studies and so forth.


Impact Analysis
One aspect to include in the documentation supporting your Code Change Request is information on the benefits likely to be achieved and the costs of implementing it.

Proponents of Code Change Requests should also bear in mind the availability of suitable means to verify compliance. This problem can arise when requested changes are written such that there are no existing tools or models that can be used to evaluate whether or not a design or construction actually conforms to the provision. A related issue is the implications of Code Change Requests for the existing building, fire or plumbing Code enforcement infrastructure. Therefore, a Code Change Request should include information on conformity verification and enforcement implications, including available resources. Where the requested change has major cost or enforcement implications, the Code committees may ask that a detailed impact analysis be provided.

Timing
Although suggestions for changes to the National Model Construction Code Documents are welcome from anyone at any time, the Codes are revised and published according to a schedule and there may be a delay between the submission of a Code Change Request and its publication in the relevant Code, even if the request has clear sailing through the Code committee and public review processes.

Summary
Code Change Requests should provide sufficient information to Code committees to demonstrate that there is a problem with certain existing requirements or an omission in those requirements, that a change is needed, and that the requested change is the right change.

Each request should answer the following questions:

What is the problem?

What is the proposed solution and how does it address the problem?

Which of the stated objectives and functional statements of the Code will the proposed solution assist in achieving?

What are the cost/benefit implications?

What are the enforcement implications?

Requests should be clearly stated and should address generic or widespread technical issues and avoid administrative issues.

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