Stairs of all types have been used since ancient times, and because they are inherently hazardous, people have been falling on them, getting hurt or even killed in the process. In North America tens of people die and tens of thousand people get injured every year from the falls on stairs. The American National Council on Compensation Insurance estimated in 2001-2002 that the cost of such fall injuries was second only to those caused by motor vehicles.
The vast majority of stairway falls result from a loss of balance, just as falls are on the level. Please see our OSH Answers document on Prevention of Slips, Trips and Falls.
A very common contributing factor is neglecting to use handrails. The consequences can be quite nasty.
Because stairway accidents can cause severe injury and even death, building codes for stairs and ramps are justifiably very rigorous. Good design can substantially reduce the potential for mis-stepping by providing us with the means to retrieve our balance, but even the best design cannot eliminate falling hazards entirely. The need for proper design also applies to ramps. The fact is that some incidents can be caused by inattention and unsafe behaviour.
The best approach to minimize the hazard of falling down stairs is to encourage the building of well-designed stairways, combined with training focused on raising our awareness of the potential for disaster.
Figure 1 shows the recommended dimension ranges for all the important elements of stairways.
A - Optimal range: 30º-35º
B* - Handrail height: 80-96.5 cm
C* - Riser height: 12.5-20 cm
D* - Step width: 90 cm min.
E* - Tread depth: 23.0-35.5 cm
Within a staircase, treads shall have a uniform run and tread depth that does not vary more than 0.6 cm*.
* Values are from the National Building Code of Canada (2005). Always check with your local jurisdiction as requirements are different in each area.
The maximum range for a stair slope is 20º-50º. However, because the majority of people prefer a slope of 30º-35º, this is the recommended range.
Steeper stairs change the way you climb them because the steeper they are the more effort you exert. The ratio of riser height and tread depth has to be adjusted accordingly. (See Figures 2 and 3)
From: Kodak's ergonomic design for people at work. 2nd ed. John Wiley & Sons, 2004. p.244
The dimension of risers or treads in a stairway should not vary more than 1 cm. When doors open directly into the stairwell, a 50 cm-wide platform should be provided beyond the swing of the door. The recommended maximum number of steps between landings is 18, with no more than two flights without a change of direction. The depth of any landing should be at least equal to the width of the stairs.
To reduce the risk of slipping on stairs, non-slippery surface on the whole steps or at least on the leading edges is crucial. Such a surface can be made of rubber, or metal or painted with special slip-resistant paint. Regular maintenance of the stairs in good repair plus good housekeeping can reduce hazards for tripping.
Attempts to design aesthetically pleasing stairways including handrails must not compromise functionality.
The prime function of the handrail is for holding as support while going up or down stairs.
It is therefore crucial to be able to grasp it quickly, easily and firmly if you should start losing your balance.
Figure 4 shows the recommended cross-section and dimensions of a good handrail. Ideally the cross-section should be round (diameter 4-5 cm, with circumference of 12-14 cm) to allow for a good firm grip.
You should be able to run your hand smoothly along the entire length without having to adjust your grip. You should apply the so-called "tennis-racket grip" at all times when possible.
Guardrails of at least 40 cm above the surface of the stairs are needed to prevent falls off the side of the stairs that are not equipped with a banister.
Improving visibility on stairs significantly reduces the risk for common mishaps caused by misjudging distances. Otherwise you can trip on a step or miss it completely. You can catch a heel on the edge of a step. Such mishaps are a routine cause of twisted ankles, sprained knees or more serious injuries incurred by a total fall.
Good housekeeping is also vital to stair safety:
For more information on Housekeeping see our OSH Answers documents:
Document last updated on June 16, 2010