Stairs, Guards and Handrails (NBC)
Stairs, Guards and Handrails (NBC) - Transcription
Slide 1
Good morning,
I am pleased to give you an update on the changes made to Part 3 and Part 9 of the National Building Code (NBC) regarding stairs, guards and handrails.
Slide 2
This presentation is part of a series of 13 presentations on the 2015 editions of Codes Canada.
Before I begin with the technical content of this presentation, I will speak briefly about the code development system.
It is important to note that the model Codes, which are developed by the Canadian Commission on Building and Fire Codes, must be adopted by provincial/territorial authorities to become law.
This may mean that Code requirements enacted by legislation within your province or territory might differ from what is presented here. Please check with your local authority.
Slide 3
It is also important to point out that the National Codes are not a federal regulation.
This means it is not NRC or Codes Canada that decides what goes into the Codes but you!
Codes Canada facilitates an open, transparent, consensus-based process to come up with improvements.
Over 400 committee members volunteer their time to decide on changes to the next Codes.
All committees are balanced between regulators, industry and public interest so that no single category can outvote the other two.
This process is shown on the slide:
- It typically starts with someone requesting a Code change.
- It continues with technical committees developing proposed changes.
- It involves a public review and the final approval by the Canadian Commission on Building and Fire Codes.
It's a simple process and it depends on your input.
Please go to the Codes Canada website and find out how you can:
- submit code change requests,
- participate in committees, or
- comment on proposed changes during our public reviews.
Slide 4
And before we start, here are some clarifications on the presentations themselves:
- The presentations cover only the changes from 2010/2011 to 2015 Codes and not how to use or interpret the Codes in general.
- The presentations contain only the significant changes - the details are in the handbook. Each presentation contains a reference to the relevant pages in the handbook.
- The presentations stay strictly within the scope of the National Codes and do not cover provincial or territorial variations.
Slide 5
Stepping back in time for a moment, we believe stairs were first used about 8 thousand years ago to help us navigate uneven or steep terrain.
As we evolved, so did the shapes and types of stairs.
Nowadays, we use stairs to move from floor-to-floor inside buildings and houses.
For this presentation, we will learn about changes in the 2015 NBC for:
- stair configurations,
- stair treads and risers,
- guards, and finally
- handrails.
For those of you following along in the handbook, the Part 3 changes are on pages 9 to 13 and the Part 9 changes, on pages 48 to 52.
Words are important, but making sure we all understand the words the same way is even more important.
Talking to architects, designers and manufacturers, we realized that even if we used the same words, these words had different meanings to different groups and even worse different meanings within the Code.
To clarify things in the 2015 NBC, a few terms were added, revised or aligned.
Slide 6
In our first example, I think we can all agree that a flight of stairs is a series of steps.
But is a flight the series of steps between floors? Between landings? Some other combination?
Slide 7
To make sure everyone is on the same level, the 2015 NBC now defines a flight as the series of steps between landings.
Another word problem we ran across was the confusion between two terms - run and tread depth.
For some, run and tread were thought to mean the same thing and used interchangeably, which caused headaches to both builders and building inspectors.
Slide 8
In the 2015 NBC, run is defined as the horizontal distance between two adjacent tread nosings on a stair.
Slide 9
Our last term of the day is tapered treads.
In Part 3, the Code referred to tapered tread as meaning a non-rectangular tread.
Part 9 used angled treads, meaning treads found in curved or circular stairs, and winders, meaning treads that converge to a point and are only found in dwelling units.
As you can imagine, there were a few circular discussions but an agreement was reached:
- define tapered treads and clarify that they can be used in curved flights,
- remove the term angled tread,
- keep the term winder, and
- use the term curved flight to mean flights of stairs in curved or spiral stairs.
Slide 10
Measuring a tapered tread has also been specified.
First, the expected walking line is set to be 300 mm from the inner handrail - that's the handrail on the narrower side of the tread.
Then at that distance, the minimum run must be 255 mm for dwelling units and 280 mm for public stairs - that's the same minimum size as for rectangular treads.
The NBC increased the run sizes for rectangular treads in public stairs a number of years ago, but the dimensions for tapered treads had not been revised until now.
Tapered treads in a curved flight must be uniform - the set of tapered treads having the same run and rise.
Slide 11
Stairs have upsides and downsides - they allow us to move from one level to another - but they are a factor in why people fall.
Fall data show that people are more likely to fall on stairs in their home than any other stairs.
To give you an idea of the size of the problem, in 2012, falls in stairs in homes led to just over 300 deaths, and 100,000 visits to the ER.
The cost to the health care system was 476 million dollars
A few other facts to consider those over 65 about 15% of the population account for half the falls on stairs and two thirds of the deaths related to falls on stairs. When kids fall, they are 3 times more likely to have a brain injury.
The technical committee studied the question of making runs longer and rises lower. They did a thorough review of what is required elsewhere by examining international codes, analyzed data on injuries, deaths as well as hospital visits related to falls on stairs.
The committee also looked at the data from research including those from the Stair Lab in Toronto which tested different rise and run dimensions in various configurations.
The committee weighed the health benefits against costs to builders and owners for various step dimensions and after all this work, it recommended that the run of stairs in dwelling units be increased to 255 mm.
A detailed report of the analysis is available if you are interested in understanding how the committee came to its recommendation.
Slide 12
Research has shown that people are getting taller, and if you think about your own family, there may be someone who's 5 feet tall and one who is 6'5”.
This new run of 255 mm is safer for more people because it can accommodate larger feet.
The committee's research showed that by changing the run to 255 mm, over the next five years, falls would decrease by about 13,000 injuries and around 40 deaths would be prevented.
Making the run bigger also offers a greater buffer so people can catch themselves if they were to lose their balance or trip.
Because there was little evidence or data of injuries caused by the size of the step rise, it stayed the same.
This means that home designs will have to change but this is greatly outweighed by the improved safety for people in their homes.
Slide 13
The Code did not allow spiral stairs as they were considered unsafe for a couple of reasons:
- the small or zero run at the center support, and
- the near vertical drop between floors.
However, spiral stairs were allowed elsewhere, for example in Quebec and BC, as part of the IRC, IBC, NFPA and other countries.
And home owners and stair builders wanted to use them.
The technical committee decided to look at why spiral stairs weren't allowed in the NBC and concluded that the stairs were perceived unsafe with no evidence supporting this.
The 2015 NBC now allows the use of spiral stairs in dwelling units and Part 9 buildings with some restrictions.
Spiral stairs are allowed:
- as secondary stairs in dwelling units, and
- as a means of egress of an area serving no more than 3 persons in both dwelling units and other Part 9 buildings, such as for:
- 1 bedroom in a loft,
- a 25 m² mezzanine (270 square feet) in an office, and
- a 10 m² mezzanine (100 square feet) in a mercantile occupancy.
They are not allowed as exits.
Because of the inherent design of spiral stairs, the minimum stair width and clear height are different from other stair configurations.
These construction parameters are mainly based on the Safety Code NFPA 101 (National Fire Protection Association).
Slide 14
Considered unsafe and not allowed in the Code was a flight of stairs with both tapered and rectangular treads.
Research showed that when going down stairs, moving from wider to narrower runs leads to missteps and falls.
Now the 2015 NBC allows a stair flight to have both tapered and rectangular treads with restrictions on run dimensions:
- the size of tread, and
- the placement of handrail.
Slide 15
So for mixed run stairs, the tread for both the rectangular and tapered treads use the same run size at the 300 mm walking line.
Or when the tapered treads are at the bottom of the flight, the run of the tapered treads are the same size or greater than the run of the rectangular treads above them.
This gives more design options and greater flexibility without compromising user safety.
Slide 16
Just to clarify, winders continue to be allowed in dwelling units.
Slide 17
Open risers are a neat architectural feature but can be problematic.
People who have some limitations on their mobility, such as leg braces, prosthetics, canes or crutches, use the riser to guide where they place their foot or cane. The riser increases their safe use of the stairs.
Open risers can also be disorienting if we look at these stairs in the bright sunshine.
Slide 18
We lose the contrast and the stairs are no longer clearly visible.
Open risers are no longer permitted in Part 3 public stairs.
The 2015 NBC has not eliminated them completely, but instead limits their use to:
- private stairs,
- fire escape stairs,
- service stairs,
- all Part 9 buildings, and
- industrial occupancies other than storage garages.
Slide 19
The NBC had restricted the use of ornamental guards.
It was thought that they would encourage climbing.
This had created frustration among consumers and industry, especially because there is no documented rationale nor benefit for this restriction.
In fact, the introduction of the requirement in 1975 and the following amendments that expanded the requirement to more locations were not supported by evidence.
It was difficult to determine if falls were related to climbing on guards or from other events.
The available statistics that related to injuries were generally attributed to other factors, such as children falling through openings or climbing on adjacent chairs or tables, etc.
So the 2015 NBC has been changed to relax restrictions on climbability providing flexibility and choice for using ornamental guards where the elevation difference is not more than one storey.
Slide 20
We are all aware that the size of openings in a guard can be a significant safety issue as we don't want kids caught in or falling through openings.
In the previous edition of the NBC, guards in industrial occupancies had the same limits on the size of openings as all other guards.
But other Canadian and international regulations allowed larger openings in these industrial applications.
The 2015 NBC is now harmonized with these regulations and guards in these occupancies are allowed to have openings of up to 535 mm.
Slide 21
A guard is a barrier to prevent someone from falling from one level to another so the height is an important factor.
In the past, it was accepted that guards found in a flight of stairs could be lower than other guards, such as ramps or landings.
The only reason was to let the top of the guard be used as a handrail.
With the population's average height increasing, the need for a lower guard in stairs was re-evaluated.
The 2015 NBC now requires the guards in public spaces to be 1070 mm for all locations stairs, ramps and landings.
Slide 22
So now that the guards are higher, the maximum height of the handrail was also looked at.
The research showed that having a handrail at the top railing of a 1070-mm guard works just as well as the lower height.
The Code increased the maximum height of a handrail to be the same as the minimum height of guards - 1070 mm.
So what does this mean:
- more design flexibility,
- handrails and guards on stairs and landings can all the same height,
- easier design of the handrail assembly as a guard, and
- no need to have an additional handrail.
Just to clarify, the height of handrails for accessible ramps has not changed.
Slide 23
In arenas and stadiums, the Codes allow steep aisles with steps.
But the NBC did not require handrails in these aisles with steps.
Based on research and international practices, this exemption was reconsidered.
The NBC now requires handrails in aisles with steps.
The Code allows many different configurations for these handrails as this improves safety without impacting crowd circulation.
Slide 24
In the 2010 NBC, problems were noted with some of the requirements relating to the continuity of handrails.
Some didn't reflect the intent stated in the Appendix Note and others limited design options and were confusing.
Some requirements were reworded to clarify any confusion and others were revised to reflect the intent.
An example of these clarifications is that for stairs with winders in Part 9 dwelling units, the handrail cannot be interrupted.
Slide 25
To quickly review, please note the following:
- the Code now defines run, flight and tapered tread,
- we know the minimum dimensions of a tapered tread, and
- the run of stairs in homes has been increased to 255 mm but the rise has not changed.
The NBC now allows:
- a mix of tapered and rectangular treads in homes,
- spiral stairs in very specific places,
- the use of ornamental guards in homes,
- large openings in industrial guards, and
- the top of the guard in stairs to act as a handrail.
These changes allow more design flexibility.
The Code no longer allows open risers in public stairs, but they can still be used in homes and a few other specific places.
Guards in stairs must now be the same height as guards for landings and ramps.
Handrails are required in stadiums and arenas.
And the 2015 NBC clarifies that the handrail must be continuous in stairs with winders.
Slide 26
I have covered a lot of information in today's presentation. The handbook is a useful resource if you want to review the topics from this presentation in more detail.
It covers the majority of technical changes that were implemented in the 2015 National Building Code, National Fire Code, National Plumbing Code and National Energy Code for Buildings.
The handbook can be purchased on NRC's virtual store as a downloadable PDF or as a hard copy.
Slide 27
Contact Information
| Autre titre | Stairs, Guards and Handrails (Part 3 and Part 9 of the National Building Code of Canada: 2015) |
|---|---|
| Téléchargement |
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| DOI | Trouver le DOI : https://doi.org/10.4224/40002100 |
| Auteur | Rechercher : 1 |
| Orateur | Rechercher : Joseph, Collinda1 |
| Affiliation |
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| Format | Vidéo, Object d'apprentissage |
| Sujet | Codes et guides; construction; bâtiment; NRCCode |
| Date de publication | 2015 |
| Maison d’édition | National Research Council of Canada |
| Publication connexe | |
| Langue | anglais |
| Exporter la notice | Exporter en format RIS |
| Signaler une correction | Signaler une correction (s'ouvre dans un nouvel onglet) |
| Identificateur de l’enregistrement | d0bb4b3e-2ace-429c-9df1-9712df80c8c9 |
| Enregistrement créé | 2021-05-04 |
| Enregistrement modifié | 2022-06-21 |
- Date de modification :