The overlap on a step must be ≥ 10 mm. The rise in a flight of stairs should be consistent. If it is not possible to maintain a consistent rise, it is permissible to reduce the rise from the starting level and starting step by a maximum of 15 percent. It is only permissible to increase the rise in exceptional circumstances and with good reason, e.g. when a moving machine is involved.
It is particularly important that the last step before a platform is the same height as all the others, otherwise that is where the most accidents happen.
The headroom, i.e. the free space above the stairway as measured in a plumb-vertical line, should be at least 2,300 mm throughout. The clearance, i.e. the free space above the stairway as measured at a right angle from the pitch line, must be at least 1,900 mm.
The standard requires that a stairway used in normal circumstances should be at least 600 mm wide, although 800 mm is better. If several people will be using the stairway at the same time, a minimum width of 1,000 mm is stipulated. In special circumstances, which must be evaluated using risk assessments, the minimum permissible width can be reduced to 500 mm.
Individual flights in a stairway must not exceed a height of 3,000 mm. Once this height is reached, a platform must be integrated that is at least 800 mm long and the same width as the stairway.
The steps on stepladders must be at least 80 mm deep. The height of a single step – also referred to as the rise – must not exceed 250 mm. The guideline value for overlap is also ≥ 10 mm.
There should be a usable clearance of between 450 and 800 mm – ideally around 600 mm – between the guard-rails which must be fitted on both sides.
The headroom (the free space above the stepladder as measured in a plumb-vertical line) must be at least 2,300 mm throughout, while the clearance (the free space above the stepladder as measured at a right angle from the pitch line) must be at least 850 mm.
Stairways with straight flights are safer than stairways with flights or partial flights that feature curves or turns. In the case of stairways with curves or turns, it is better to ensure these turn in only one direction, i.e. either always to the left or always to the right. However, curved staircases are very unusual in industrial environments.
The treads on stairways must feature an anti-slip surface in areas where there is an increased risk of slipping. However, it is advisable to use anti-slip materials or surfaces as a general rule.
If the front edges on steps are rounded, they should have as small a radius of curvature as possible. If a stairway is outdoors, additional measures are also required to protect against slip hazards caused by weather conditions. Such measures could include an adequately sized canopy.
To ensure users can move up and down stairways safely, it is essential that the steps, and particularly the edges of the steps are highly visible and easily identifiable. This means that the stairway must be adequately lit. Guideline for workshops AST 7/1 “Artificial lighting”, which is issued by the relevant German institution for statutory accident insurance and prevention, requires that stairways are lit with a nominal lighting level of 100 lux at a height of 0.2 m above the surface of the steps. Safety can be further improved by using risers and treads in different colors or highlighting the edges of steps with colored markings.