What does it mean when a design philosophy is based on providing means of escape, but the building is based entirely on keeping people locked up?
Emergency lighting standards typically assume one of two conditions, either stay or go. The conventional approach to staying put is for a UPS (uninterrupted power supply) to take over in the event of the normal electricity supply being lost. This is stand-by lighting and is the primary back-up system in use in prisons in the UK. A generator supplies sufficient power to enable the prison routine to continue about its usual business. But there is also an integral battery back-up to the UPS back-up and it’s here that we see a change to standard design procedure.
According to standards, if it’s not stand-by, then it must be escape lighting; not a term that meets with much approval in the Ministry of Justice. Escape lighting is usually designed to provide 0.5 – 1lx along designated egress routes from a building in the event of evacuation, but it’s also designed on the idea that it’s all for one and one for all in the process, rather than guards and their charges, which suggests an entirely different psychological dynamic.
The lowest illuminance level given by the UK Health & Safety Executive (HSE) suggests an average working illuminance of 20lx for those areas where there is little visual acuity required, with a 5lx minimum measured, and it is close to these levels that the integral battery back-up is designed to operate. This level of illumination is provided in association areas and circulation areas within the prison, but there is no emergency lighting in cells, on the basis that, provided there’s no risk to life, the safest place to hold a prisoner is behind a locked door. The enhanced illuminance levels are also provided at control panels as staff may well need to stay in communication via cell call and gneral alarm systems.
Design of luminaires is a vital aspect of prison management, of course. Anti-ligature design is a must but fixtures must also be physically robust, tamper resistant and built in such a way that items cannot be hidden within them. It is also a requirement that fixtures are not capable of being used as weapons. And beyond this stringent list of things that a luminaire design must satisfy there is also the job that the fixture was intended for in the first place; providing a specified level of illuminance with a specified colour performance and switching capability. It is not surprising to hear that there there is a defined test methofology for any luminaires put forward for use by manufacturers.
Not many of us have the experience of having so much time on our hands that we can turn our minds to ways of stripping down a light fixture that was designed not to be stripped down, or of finding a way to make a cup of tea in the middle of the night, as was described to me in fine detail recently. It is little wonder that such a rigorous testing regime is in place for such equipment.
Evacuation practices are not generally advertised. A Freedom of Information request in 2010 asking for evacuation plans for two UK prisons as denied, with this response: ‘The secure management of an incident would be jeopardised if prisoners or those acting against the Prison Service were alerted to these emergency protocols.’ which reminds us all that normal practice means something different in these establishments. What we do know is that self-evacuation is not an option.
- A one-day Lux conference on Emergency Lighting takes place on Thursday 25 February at the Cavendish Conference Centre, London. Delegate places are free to facility managers, energy managers, consulting engineers and other independent specifiers. To register for a free place at the conference, click HERE.
- A special Lux webinar on best practice in lighting for prisons takes place on Wednesday 8 June 2016. It will cover the latest thinking and research in illumination for custodial environments including adult prisons, young offenders’ institutions and secure mental health units. To visit our upcoming webinars page, click HERE.
Picture: Nino Photography