PROPOSED CHANGE TO THE 2012 BUILDING CODE O. REG. 332/12 AS AMENDED

Transcription

1 Ministry of Municipal Affairs PROPOSED CHANGE TO THE 2012 BUILDING CODE O. REG. 332/12 AS AMENDED CHANGE NUMBER: SOURCE: B Ontario-NBC CODE REFERENCE: Division B / Division B / DESCRIPTION OF THE PROPOSED AMENDMENT These proposed changes clarify the treads and riser requirements and harmonize with the model National Building Code of Canada. EXISTING 2012 BUILDING CODE PROVISION(S) Treads and Risers (1) Except as permitted for dwelling units and by Sentence (1) for fire escapes, steps for stairs shall have a run of not less than 255 mm and not more than 355 mm between successive steps. (2) Steps for stairs referred to in Sentence (1) shall have a rise between successive treads not less than 125 mm and not more than 200 mm. (3) Except in fire escape stairs and where an exterior stair adjoins a walkway as permitted by Sentence (3), risers, measured as the vertical nosing-to-nosing distance, shall be of uniform height in any one flight, with a maximum tolerance of, (a) 5 mm between adjacent treads or landings, and (b) 10 mm between the tallest and shortest risers in a flight. (4) Except in fire escape stairs, treads, measured as the horizontal nosing-to-nosing distance, shall have a uniform run with a maximum tolerance of, (a) 5 mm between adjacent treads, and (b) 10 mm between the deepest and shallowest treads in a flight. (5) Treads and risers shall not differ significantly in run and rise in successive flights in any stair system. (See Appendix A.) (6) Where angled treads are incorporated into a stair, the treads in all sets of angled treads within a flight shall turn in the same direction. (7) The slope on treads or landings shall not exceed 1 in 50. (8) Except as permitted by Sentence (10), the top of the nosing of a stair tread shall have a rounded or bevelled edge extending not less than 6 mm and not more than 13 mm measured horizontally from the front of the nosing. (9) The front edge of stair treads in exits and public access to exits shall be at right angles to the direction of exit travel. Building and Development Branch Page 1

2 (10) If resilient material is used to cover the nosing of a stair tread, the minimum radius or bevel required by Sentence (8) is permitted to be reduced to 3 mm. A (5) Stair Tolerances. The term shall not differ significantly assumes normal construction tolerances Ramps and Stairways (1) Except as permitted by Sentence (2), Article and Subsection , ramps and stairways that do not serve as exits shall conform to the dimensional, guard, handrail and slip-resistance requirements for exit ramps and stairways of Sentence (7) and Articles and to (2) Ramps and stairways that do not conform to the requirements of Sentence (1) and are intended only for occasional use for servicing equipment and machinery are permitted, (a) to serve service rooms and service spaces, and (b) in industrial occupancies. PROPOSED CODE CHANGE Amend Articles and as follows: Treads and Risers (1) Except as permitted for dwelling units and by Sentence (1) for fire escapes, steps for stairs shall have a run of not less than 280 mm between successive steps. (2) Steps for stairs referred to in Sentence (1) shall have a rise between successive treads not less than 125 mm and not more than 180 mm. (3) Except as permitted in Article and except for fire escape stairs, stairs that are principally used for maintenance and service, and stairs that serve industrial occupancies other than storage garages, steps for stairs shall have no open risers. (34) Except in fire escape stairs and where an exterior stair adjoins a walkway as permitted by Sentence (3), risers, measured as the vertical nosing-to-nosing distance, shall be of uniform height in any one flight, with a maximum tolerance of, (a) 5 mm between adjacent treads or landings, and (b) 10 mm between the tallest and shortest risers in a flight. (45) Except in fire escape stairs, treads,, shall have a uniform run with a maximum tolerance of, (a) 5 mm between adjacent treads, and (b) 10 mm between the deepest and shallowest treads in a flight. (56) Treads and risers shall not differ significantly in run and rise in successive flights in any stair system. (See Appendix A.) (7) The slope on treads or landings shall not exceed 1 in 50. (8) Except as permitted by Sentence (10), the top of the nosing of a stair tread shall have a rounded or bevelled edge extending not less than 6 mm and not more than 13 mm measured horizontally from the front of the nosing. (9) The front edge of stair treads in exits and public access to exits shall be at right angles to the direction of exit travel. Building and Development Branch Page 2

3 (10) If resilient material is used to cover the nosing of a stair tread, the minimum radius or bevel required by Sentence (8) is permitted to be reduced to 3 mm. A (6) Stair Tolerances. The term shall not differ significantly assumes normal construction tolerances Ramps and Stairways (1) Except as permitted by Sentence (2), Article and Subsection , ramps and stairways that do not serve as exits shall conform to the dimensional, guard, handrail and slip-resistance requirements for exit ramps and stairways stated in Sentence (7) and Articles and to (2) Ramps and stairways that serve service spaces or industrial occupancies need not comply with Sentence (1) provided, (a) they are intended only for occasional use for servicing equipment and machinery, and (b) they do not serve as exits. RATIONALE FOR CHANGE Problem/General Background Open risers on public stairs are hazardous to ambulant persons with disabilities and cause a visual distraction. Change Number 709 Article (6) Sentence (6) suggests that mixed run flights are allowed in Part 3 buildings which is not the intent of the Code. This brings the OBC Part Three into line with, first, the OBC Part Nine, specifically , for the minimum run and maximum rise for public stairs. Secondly, the OBC is brought into line with the NBCC requirements (dating back to the 1995 edition) for public stairs rise and run. Third, and most important, this brings the OBC into line with the overwhelming research findings on stair rise and run dating back decades and based on studies in the US, UK and Canada. Fourth, this brings the OBC into line with formal recommendations coming from adopted policies of major public health associations serving Canada and the USA and many of their individual, public health professional members in Ontario and beyond. The revisions are needed to bring, to a reasonable minimum standard, the minimum requirements that have an effect on stair safety as well as on egress performance. Justification/Explanation These proposed changes would harmonize requirements with the model National Building Code of Canada. People who wear leg braces or prosthetic devices need a solid riser to guide their foot up over the riser to the next step and, to maintain balance, those who use canes or crutches place them against the riser of the step above the one they are on to move up. The British Colombia Building Code has had such a requirement for years, as well as US Codes. Furthermore, this issue has been addressed by many international regulations as stated in the International Best Practices in Universal Design, a Global Review, published in Building and Development Branch Page 3

4 This proposal would apply to stairs in public areas. Article has been updated to clarify that the requirement on solid risers will apply to access to exit public stairs as it is proposed for Part 9 buildings. Change Number 709 Article (6) This proposed change would harmonize requirements with the model National Building Code of Canada. The deletion of Sentence (6) reduces enforcement and interpretation problems. The removal of Sentence (6) turns to the new Sentences (4) and (4) that clarify under which conditions curved flights are allowed. The changes are based on ergonomics studies and epidemiological studies examining the performance of stairs with various rise and run dimensions. Rise heights need to be lower and run dimensions need to be larger than the OBC has permitted for some time. For example, Ontario has a hospitalization rate about twice that for the entire USA for stair-related injuries and, from etiological and other ergonomic studies we know that both rise and run affect safety from falls. The attachments to this proposal provide much of the background on this issue, including highlights of research as well as advocacy by public health professionals in Canada, especially from those practicing in Ontario (with the latter being a record of public comments submitted for the NBCC public review process, in the autumn of 2014 in relation to step dimensions, in which over two thirds of the nearly 90 public comments advocated adoption of the widely used, so-called "7-11" step dimension rule calling for rise not exceeding 180 mm and run of at least 280 mm for stairs. Cost/Benefit Implications As it is more expensive to build open riser stairs, there is no-cost impact associated with this proposal. Change Number 709 Article (6) This reorganization does not have any cost implication The added costs related to lower rise heights and to deeper treads are more than compensated for by the improved safety. For example, the current OBC rules allowing 200 mm rise and as little as 255 mm run result in stairs having over twice the risk of falls as with the proposed 180 mm by 280 mm standard. For Ontario, this difference alone could account for approximately one billion dollars of additional societal injury costs per year. Injury prevention is but one benefit of the improved standard, egress efficiency under emergency conditions and improved usability for all users, notably seniors, are also improved. Both are important to public health broadly. Enforcement Implications None. Building and Development Branch Page 4

5 Change Number 709 Article (6) Can be enforced by the available infrastructure without an increase in resources. May facilitate enforcement and determination of compliance There is no implication for enforcement as the diligence that must be exercised in plan examinations and inspections is essentially the same as currently needed. Who is Affected Designers, building officials, builders and manufacturers. Objective Based Analysis Provision Objective/Functional Statement Division B (1) [F10-OS3.1][F30-OS3.7] (2) [F10-OS3.1][F30-OS3.7] (3) [F10-OS3.1][F30-OS3.7] (3) [F73-OA1] (4) 3 [F10-OS3.7][F30-OS3.1] (5) 4 [F30-OS3.1][F10-OS3.7] (6) 5 [F30-OS3.1][F10-OS3.7] (7) 6 [F30-OS3.1][F10-OS3.7] (8) 7 [F30-OS3.1] (9) 8 [F30-OS3.1][F10-OS3.7] (10) 9 [F30-OS3.1] 10 Building and Development Branch Page 5

6 Provision Objective/Functional Statement Division B (1) OTHER SUPPORTING MATERIALS Building and Development Branch Page 6