Technical Insights: Handrail Profiles

TECHNICAL INSIGHTS

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Handrail Profiles

by Howard Moutrie

Since 2010, AS1428.1 permits handrails to be round or elliptical, though for many years, only round handrails were permitted. Is this restriction valid and can other shapes be just as functional?

Firstly, lets look at how handrails have developed. Traditionally they were made of timber, were square or rectangular in shape with a rounded top. See the typical profile in the image below. Much of the bulk of these handrails was for structural reasons – to span between supports and to withstand the horizontal forces which may be applied.

With the increased use of steel, pipe handrails became popular, particularly in non-residential buildings. The use of a circular section makes sense - looking at the profile of a gripping hand, see below, it can be seen that a circular shape results, particularly at small diameters, but it can also be seen that at larger diameters, a more elliptical shape is formed. But steel or timber doesn’t easily form into this shape, though extruded aluminium does. Architects often like to use a minimal flat horizontal section, but under AS 1428.1 these are not permitted. Is the restriction of the profile to circular or elliptical valid?

The handrail has 2 primary functions, firstly as a guide as a person moves up or down the stair or ramp, and this may include a pull-up function when ascending a stair or ramp and secondly, it can be used as a stabiliser when a loss of balance has occurred. The latter requires a higher level of 'gripability'. Templar, in his book The Staircase, suggests that in this latter condition it is important to provide as much hand area to the handrail as possible to avoid tissue damage and discomfort and thus handrails with elaborate mouldings are undesirable. Maki and Fernie, in their research concluded that for the elderly, or people with reduced wrist and forearm function, a handrail with a wide flat upper surface may limit the amount of force that can be applied and thus is not ideal. Templar also considered the handrail with respect to injury from hitting it during a fall but acknowledged that recessing the handrail to avoid this issue would not be suitable for people with disabilities. In the end he concluded that a 38mm round handrail is most effective for gripping but is not the best shape to push away from or for injury reduction.

More recent research published in 2009 by Dusenberry et al, found “the most important feature essential for functional handrail profiles are protrusions, or lips, that create finger purchases into which users can place fingers and thumb when grasping both sides of handrails.” Their research found that while the commonly used 51mm round handrail was functional, handrails did not have to be round to be functional. They concluded that “symmetric handrail shapes that are at least 32 mm (1- 1/4 in) and not more than 70 mm (2-3/4 in) wide, with a height above the widest portion of the profile not exceeding 19 mm (3/4 in) are sufficiently graspable as long as there is a recess on both sides at least 8 mm (5/16 in) deep. Each recess should achieve this minimum depth no farther than 22 mm (7/8 in) below the widest portion of the handrail and extend down at least 51 mm (2 in) from the top of the handrail. Additionally, the portion of the height of each recess that is at least as deep as 8 mm (5/16 in) should be at least 9.5 mm (3/8 in). In all aspects tested, the probability of loss of grip on a handrail with this shape is essentially the same as or better than for a 51-mm (2 in.) diameter round shape.” They also determined that a wider, flatter handrail tended to reduce the impact of the handrail support tending to break a person’s grip – the narrower the handrail, the greater proportion of the handrail width would be taken by the handrail support.

So, considering this research it would seem that a wide, flat bar would be a suitable handrail, though not permitted under AS 1428.1. I note that this research was published after AS 1428.12009 was written and thus was not considered.

In 2002, Nagamachi et al, published Japanese research aimed specifically at the elderly. This is important research because the elderly tend to be more reliant on handrails, but we need to also consider that people in Japan tend to be physically smaller than those in Australia. With respect to the size of the handrail, they recommended a diameter of 35mm and that a larger diameter my not be graspable by the elderly if attempting to arrest a fall. The research also found that many of the subjects found that a handrail height of 850mm too high.

What do other Standards or countries require? The latest ISO Standard, requires a maximum dimension of 45mm and a minimum dimension of 32mm in any direction. It permits a square shape provided that the corners are rounded to a 15mm radius. Thus, at its smallest the handrail would be essentially circular but at its largest a 15mm flat section would be possible. As there are no commercially available sections, that I am aware of, that meet this criteria, this would be limited to timber handrails. The American Standard permits a square/rectangular handrail, within dimensional limits, and requires the edges to be rounded (but there is no specified radius). This permits commercially available sections which tend to have a 2-5mm radius on the corners. The British Standard is similar to the ISO Standard but does not specifically indicate a square profile, just round and elliptical. Finally, the GATES Standard or Guide requires a circular profile 30-40mm in diameter or a non-circular profile with a maximum width of 57mm and a total perimeter dimension of 100-155mm. Interestingly, the GATES Guide shows an elliptical handrail with a vertical orientation, which the research would suggest is the least preferred option for gripability.

So where does that leave us? It seems to me that like most things there is no single answer. Certainly, using AS 1428.1 is a safe option, but consideration of other sizes and profiles is possible and not unreasonable. I certainly don’t think that rectangular profiles should be excluded as the research seems to support their use. It is obvious that the size of the handrail probably should consider its context, for example, in seniors housing a smaller handrail than in a public building, but there is sufficient evidence to suggest that the ”standard” 50mm diameter is in fact too large for circular handrails and a size of 30-40mm is more graspable. This goes back to the photos earlier in this article of the hand profile.