*ARCHIVE* - Climbing great heights
The Building Industry Authority recently commissioned a series of tests to measure the child resistance of barriers.
Testing was conducted by Alchemy Engineering & Design Limited in Wellington during August this year.
The objective of the project was to test several barrier types in addition to the standard barrier given in the Acceptable Solution F4/AS1. This provides a means of establishing compliance with New Zealand Building Code Clause F4 "Safety from falling".
Clause F4.3.4 (g) of the code states that barriers shall
- restrict the passage of children under 6 years of age when provided to guard a change in level in areas likely to be frequented by them.
The 'standard' barrier is 1.0 m high on decks or balconies to houses, with no toeholds between the heights of 150 mm and 760 mm. One of the objectives of the testing was to establish if other barriers are equally as difficult for children to climb as the standard barrier.
Nine different types of barriers were constructed. All were fabricated from aluminium then powder coated. Each test barrier consisted of a panel with a width of 1.2 m and a height of 1.0 m, and they were anchored to a timber and ply rigid base to prevent toppling or movement.
The test barriers included the barrier described in F4/AS1, along with barriers 1.0 m high with horizontal rails and inward returns, solid barriers with various toehold options, and variations on vertical tube infills.
Children aged from 9 months old to 4 1/2 years old were asked to climb, once parental or custodial consent had been obtained.
The method used was to put two different types of barriers at the same time on a timber platform, with rubber safety overlay, and to get the children by age group to attempt to climb each barrier.
For each barrier type each child was timed for a successful climb or failure to climb. Children 1 year and under didn't have enough strength and co-ordination to pull themselves up and over the barriers. Also the barrier was too high. This age group appeared to be happy to stand holding on to the barrier and look through it.
The 2-year olds were able to use their strength to more effect and were a little taller. They were able to reach to the top rail. This group is possibly at the most dangerous age, they can climb some barriers but have not yet gained the judgement to avoid injury. They were not able to climb the 'standard' F4/AS1 barrier.
The 3-year olds, again like the 2-year olds, were more co-ordinated, had more strength and were taller so they were able to use their knees on the rails, and feet on the toeholds far more effectively to lever themselves over the barriers. Only a few, however, could climb the 'standard' barrier.
The 4-year olds didn't have much trouble with any of the barriers because they were able to think the process through before attempting to climb the barrier. On several occasions if they failed to climb on the first attempt they succeeded on the second attempt. This age group also displayed enough judgement in general not to excessively risk injury.
The only barrier that prevented all but one 4-year old child from climbing it was a vertical tube infill with a toehold at 100 mm from the ground and top rail at 1.0 m. The children weren't able to wedge or place feet or knees on a horizontal member to assist them in a successful climb because the tubes were vertical.
One significant observation from the testing was in the toeholds test where the barrier had narrow ledges at various heights. Children tall enough to reach the top rail were able to get sufficient toehold to climb the barrier, even though the toehold was only 10 mm wide.
Strength in the arms and problem solving were skills the older children used to get over the barriers. The older children had more strength in their arms, which made it easier for them to climb the barriers by simply pulling themselves up. Also the older children solved problems of how to climb the barriers, and on several occasions if at first they failed to climb the barrier, on the second attempt they succeeded. One 3 1/2 year old child, for example, took only 10 seconds to climb a barrier on the second attempt.
The test results were similar to those of an Australian study several years ago that the BIA has used as a reference.
Conclusions
- The tests have confirmed that the barrier given in the acceptable solution is 100% effective for children under 3 years.
- The tests showed that 1-m high barriers of varying designs can be climbed by many 3-year olds and certainly by most 4-year olds.
- Children over 3 years can climb quickly. One 4-year old child scaled the different barriers in under 10 seconds.
Hamish Handley, BIA Technical Adviser, recommends that designers aim to achieve two objectives for an alternative barrier design:
- to prevent passage of children under 3 years of age, and
- to not attract older children to attempt to climb it.
Too many horizontal members or toeholds will make climbing easy.
Not being attractive to children, he says, is a requirement of the Swiss building code. A barrier should not look like a climbing frame or present a fun-type challenge.
There are many excellent examples of alternative barriers now being designed. Wandering through a city or studying architectural and lifestyle publications are good ways of getting ideas says Hamish.
Anyone wanting more details of the report can contact Hamish Handley at the BIA by phone 0800 242 243 or 471 0794 for Wellington callers, fax 04 471 0798, or email: handley@bia.govt.nz
See also BIA News No. 93, July 1999, pages 4-5 for an article on barriers.
The Department of Building and Housing offers Ministry of Housing and Building Industry Authority publications as historical reference material only, and takes no responsibility for the accuracy of the information. The Department of Building and Housing shall not be held liable for any claim for direct or indirect loss or damage as a result of reliance on the information contained in the documents.