The requirements for the safety of network playground equipment
By Karl Köhler (Berliner Seilfabrik GmbH & Co.)
Whenever the subject of safety comes up, the emotions come into play. Sentiments such as fear, trust and the willingness to face up to risk determine the extent of security that each individual will feel to be appropriate in given circumstances. And our emotions can all too easily go into overdrive when it is our most valuable asset, namely our children, that is the focus of concern. We thus need not be surprised that discussions relating to the topic of safety on playgrounds all too often develop into turbulent altercations between playground equipment manufacturers, playground operators, playground inspectors and also parents. Remarks such as "They can fall from the top there right onto the ground" and "That's the sort of site where heads can get trapped" are not uncommonly heard in this connection.
In order to provide for a more balanced view of this subject, it is advisable to take a closer look at the standard that applies to playgrounds. We can find definitions of the technical requirements designed to provide for playground safety in DIN EN 1176, the German language version of the standard. The current valid edition of this standard (DIN EN 1176:2008) has been in place since the summer of 2009. All playground equipment installed on publicly accessible playgrounds (and this also includes equipment on playgrounds in child day care centres and schools) is required to conform to the stipulations of this standard. Essentially, there are two core aspects that need to be considered:
How much safety is necessary to protect children against unpredictable risks?
How much hazard must be retained in order to ensure that children still enjoy using equipment and have the opportunity to develop self-reliance and an awareness of what represents a potential threat?
It is thus apparent that, assuming that a suitable balance between protection and fun on playgrounds is provided, this will mean that children are always exposed to a certain level of risk when using such equipment. Indeed, as is stated in the introduction to the standard: "In play provision, exposure to some degree of risk may be of benefit because it satisfies a basic human need and gives children the chance to learn about risk and its consequences in a controlled environment." Hence, the standard sets out explicit rules designed to prevent children being involved in accidents resulting in severe incapacities while minor injuries ‒ such as bruising, contusions and sprains ‒ are seen as acceptable in the light of the need to retain some level of risk.
The German version of the standard is prepared by specialist committees within the German Institute for Standardisation. The working committee with responsibility for playground equipment is made up of representatives of the various interest groups: the users, the public sector, the consumer protection organisations and the associated businesses. Berliner Seilfabrik has been represented on the standards committee for many years and, thanks to its expertise in the specific field, has been able to materially contribute to the drafting of the section "Additional specific safety requirements and test methods for spatial networks" (DIN EN 1176, part 11). This form of equipment consists of geometric, three-dimensional arrangements of ropes, cables or chains that have a certain degree of flexibility. Spatial networks of this kind can be found positioned around central masts or in the network playhouses produced by Berliner Seilfabrik. "The particular attraction of play equipment of this kind is that it is very versatile. The children can give their imagination free rein when using it. They continue to find new ways of climbing, playing with or experiencing the equipment," explains Karl Köhler, Managing Director of Berliner Seilfabrik and a member of the standards committee for more than 30 years. "Climbing within a spatial structure not only trains children's psychomotor abilities but also encourages appropriate social interaction with others. It is not the done thing to push someone else off a net ‒ on the contrary, children will give their playmates tips on where to put their feet next to climb higher."
In the past, however, height of fall from and within spatial networks has often been very divergently assessed because of a lack of appropriate information, making it necessary to define supplementary safety requirements for this form of play equipment. There are three main factors that are relevant to safety.
As children climbing a spatial network are always forced to find at least three anchorage points if they wish to make progress, it can be assumed that the level of safety in this situation is greater than, for example, when a child is standing unsupported on a platform. "Our tallest piece of network equipment has a height of 13 metres. And of course, the first time you reach the top and look down at the ground through the mesh it looks dangerous," adds Köhler. "But this does mean that the user is made aware of the risk and thus deliberately takes more care." Hence, use is made of a paradox: a piece of play equipment appears hazardous and this influences the behaviour of the user in such a way that the risk of serious injury is reduced.
In addition, the mesh size of a spatial network is also an important factor when it comes to the provision of the necessary level of protection. The important thing is that accidental falling through a net is not possible if the mesh size is appropriate as this will be automatically hindered by reflex reactions of the arms in such situations. It is here that the compromise between safety and risk is particularly evident ‒ the mesh size is the determining factor that prevents serious injury while it must also be such that an acceptable degree of risk is provided. This approach is endorsed by Karl Köhler: "Compliance with the safety standards means that children are afforded maximum protection when playing. But we also consider it to be crucial that a residual risk remains ‒ for example, of suffering a minor graze. In our era, when electronic media rule the roost in leisure terms, we see it as a challenge to give our equipment an appeal that will lure children away from the device screen and persuade them to indulge in physical play."
The average size and reach of users are the aspects that determine what mesh size is to be used. Defined in the standard is a cylinder with a height of 180 cm and diameter of 65 cm; means to prevent a vertical fall within the spatial network are mandatory unless impact attenuating surfacing is provided on the impact area for the highest point of the cylinder. In addition, maximum height of fall may not exceed 300 cm. There is an exception to this rule where there are horizontal nets positioned one on top of the other. In this case, the maximum permitted mesh size is 42 cm if the nets are placed more than 1 metre apart on top of each other.
It is the law of gravity that dictates the third safety rule in connection with spatial networks. As falls from the angled sides of pyramidal network structures cannot occur outside the equipment but only vertically within it, structural elements outside the spatial network are not relevant to safety. It is the height of fall to the next network element that thus needs to be determined. Thus, the free height of fall in spatial networks is the distance from the highest foothold to the ground, assuming that unimpeded vertical descent is possible at this site.
In addition to the assessment criteria already outlined, the angle at which elements of playground equipment meet plays an important role in connection with safety. As a general rule, angles that are smaller than 55° at heights of more than 60 cm are seen as unsafe as these represent potential entrapment sites and thus do not conform to the standard. To some extent, this safety requirement influences the form that network playground equipment can take. Both supportive framework and net structure tend to be constructed in the shape of Platonic solids so that there are no angles within the individual cells that are smaller than 60°. There are more acute angles only near suspension points, where elements run together. "In order to provide for sufficient safety at such sites, we incorporate small flat nets where network elements join up to prevent users falling into the angles," says Jörg Prechter, Product and Quality Manager of Berliner Seilfabrik, who is moreover a member of the playground equipment and playground inspector standards committee.
Besides the safety requirements for network play equipment, there is also the question of how the responsibilities for the various aspects are assigned. The standard stipulates that playground operators are primarily responsible for verifying that playground equipment itself and its installation comply with stipulated safety requirements. This implies that operators bear a legal obligation with regard to public safety and thus need to carry out regular inspections and maintenance work. It is the responsibility of playground equipment manufacturers, on the other hand, to make sure that their products comply with the valid version of the standard at the time of supply and thus meet the latest technological requirements. Equipment must also be installed in accordance with the stipulations of DIN EN 1176 and here it is the responsibility of the corresponding installation firm to make sure this is so. Only once a playground has been approved by an inspector accredited in accordance with German standard DIN SPEC 79161 can it be made available for public use.
In conclusion it is worth noting that, as a result of the continuous further refinement of the requirements for playground spatial networks by the standards committee, serious accidents involving this type of equipment have been almost completely eliminated.
Children and youngsters rushing here and there, screams of pleasure, high spirits and laughter ‒ as soon as a trampoline park opens its gates, it takes no time at all until the visitors arrive.
Fall protection surfaces vary in terms of cost, minimum installation thickness and cleaning and care requirements. It should be noted that the most important property of these surfaces is the safety-related shock absorption. This is the surface's ability to reduce the impact energy that occurs when a child falls from a piece of play equipment. It prevents a critical, even life-threatening, injury.
