Gates – balancing the need for safety without jeopardising security
According to the guidance issued by the HSE (Health & Safety Executive) all manual – and automatic – gates should be safe. But there are undoubtedly situations where consideration must be given to ensuring the measures taken to ensure the safety of the installation do not override an overarching requirement for site security.
Safety by design
A starting point for any automated – or manual – gate installation, regardless of any specific enhanced protection issues, should always be to design out any potential safety hazards at the beginning of the project. The principle here is simple: if the gate installation is given careful consideration from a safety perspective from the outset, then the time spent represents a worthwhile investment as it will minimise the need for any costly retrofitting of measures to address critical issues.
Mind the gap
There are a number of design factors which need to be factored into any automated (and often manual) gate. This will include taking into consideration the need to ensure there are no sizeable gaps around the gate or around devices associated with the gate, which could be deemed as potential trap or crushing points. The following guidance should be followed in terms of acceptable gaps. The gap must not exceed 100mm:
- above and below the gate
- between the pales of a railing style gate
- between the support post and the centre line of the gate in the case of a sliding gate
Sloped entrances which effectively create a reducing gap must also comply with this advice. In the event that the risks cannot be eliminated by design, electronic measures will be needed
Crushing and entrapment risks
Attention should be paid to the obvious crushing risks posed by a gate that opens onto a brick pillar or similar. This again can be mitigated by design, hanging the gate on the corner of the pier or moving the gate or wall to more than 500mm from the open position of the gate. If this is not possible, finger guards should be fitted to protect crushing risks at the hinge point of the gate.
Single point failure
Steps should be taken to prevent a single point failure. The latter can be achieved by including three, not two, hinges on a swing gate, incorporating a gate tether to prevent a gate leaf falling in the event of a hinge malfunction, including end stops for fully open and closed positions for both swing and sliding gates. Sliding gates are often supported by a single post and the support/guide rollers are the only method of holding the gate in the vertical, goalpost supports will eliminate this risk.
The physical approach to the gate should be designed is such a way as to ensure that no vehicle can approach at a fast speed with a view to potentially ramming the gate to gain entry. Depending on the level of security required, it may also be relevant to include additional protection for pedestrians, such as bollards or heavy landscaping to maintain segregation.
Attention should be paid to access control in a high security setting. For example, if the gate is required to protect a high-profile member of the Royal family, only trained personnel should be permitted to instigate the opening and shutting of the gate. There can be no reliance on electronic measures and the gate would therefore represent a manned – or deadman – operation.
Proactively controlling the number of vehicles who might be able to pass through the gate at any one time is also critical to maintaining an enhanced degree of site security. Any scope for tailgating activity must be ruled out, so an airlock system needs to be adopted to effectively monitor, and where necessary, hold any incoming vehicles whilst essential paperwork checks are undertaken to authorise and validate entry to (and exit from) to the facility.
In some high-risk situations, there is a need to create a ‘sterile’ zone within the airlock itself, which provides an airtight location where vehicles can neither enter nor exit the site. This originates a safe environment where suitably trained personnel can undertake additional checks, for example, a comprehensive scanning of underneath the vehicle to establish the presence of any explosives not visible to the human eye.
The width of the actual entry point into the premises must be conducive to enabling only one vehicle to pass at a time; this also dictates the requirement to incorporate segregated entry and exit routes for all motorised traffic.
Equally it is imperative that segregated access is in place to enable the controlled movement of any on-foot visitors. This is likely to require the inclusion of a turnstile operation which is designed to accommodate only one person at a time. Alternatively – or sometimes in addition, employing an access card with a dedicated PIN can also provide a further layer of security before admission is authorised.
Founder of Gate Safe
Gate Safe was set up in 2010, in the wake of the tragic deaths of two children crushed by automated gates, in separate accidents. The charity’s aim is simple – to put a stop to any further accidents or fatalities occurring as a result of an unsafe electric gate or barrier installation.