Emergency light / illuminated sign

[Adam Jackson]

Is an illuminated sign also an emergency light?

A few scenarios:

1)
Someone has put their escape sign on the light to illuminate it, but that surely renders the light ineffective compared to its design specification?

2)
What about purpose built iluminated signs - e.g. the bulkhead design with the escape sign on the front of it?


Or should signs and lights be separate, end of story?


I keep getting conflicing advice on this - is there a definitive answer?

[Graeme]

The sign must conform to the colours of ISO 3864, which defines that exit and first aid signs must be white with green as the contrast colour. The ratio of luminance of the white colour to the green colour must be between 5:1 and 15:1. The minimum luminance of any 10mm patch area on the sign must be greater than 2cd/m2 and the ratio of maximum to minimum luminance shall be less than 10:1 foreither colour.

Internally illuminated exit signs are pre-tested to ensure they meet these requirements, provided that they comply with EN 60598-2-22.
If the sign is designed to be externally illuminated, considerable care must be taken by the system designer to see that these conditions are met.
Even though an emergency luminaire must be sited within 2 metres from the sign calculations should still be made to check that the sign is adequately illuminated.

piece of cake

[AnthonyB]

Emergency lighting has a number of different purposes in a building, of which three are commonly used:

1) Escape lighting - providing sufficient levels of light along an escape route so that a person can safely navigate their way to safety should the normal lighting fail
2) Emergency safety lighting - providing sufficient levels of light in an area of high risk so that a person will not sustain injury if the normal lighting fails (e.g. lift machine rooms)
3) Emergency lighting of safety features - providing sufficient levels of light so that safety & warning signs, fire extinguishers, fire alarm break points, etc can be identified and used should the normal lighting fail.

The "exit box" or internally illuminated exit sign is one way of achieving element (3) of an emergency lighting system, however by design are not intended in themselves to contribute to element (1), the illumination of an escape route.

Both scenarios (1) & (2) in the original post are types of exit box - you can either go for the purpose made unit with the transparent cover incorporating the legend or use a self adhesive legend on a normal emergency luminaire - cost & aesthetics usually determine which is used.

Signs and lights are not seperate, it's the purpose for which you are using the lights that is the key.

You may need escape lighting and thus place units to meet the light & placement requirements (a certain amount of lux of illumination for a particular type of space with specific cover for stairs, junctions, etc).

You then need to decide if the escape lighting units will provide the required level of illumination of your exit signage - if so, you can use normal signs and the task is over. If not you can either:
a- add additional luminaires adjacent to your signage
b- install "exit boxes"
c- if continuously exposed to a suitable light source to 'charge' them up use photoluminescent signs

Of course in some premises the use of the "exit box" was a requirement of legislation (cinemas, theatres, licensed premises, etc) and had to be provided in addition to other emergency lighting.

The illuminated sign/exit box is therefore a type of emergency light to fulfil a particular requirement of the British Standard as well as in particular codes

[Adam Jackson]

Thanks both, that's some useful information.

Just so I'm clear. If EL is needed for escape routes then the 'exit box' style described above is not suitable as an EL and additional EL must be provided, unless the exit box is specifically designed to be both an illuminated sign and EL? Have I read that correctly or am I being a bit of a 'tard?

[AnthonyB]

A lot depends on the lighting output. Most purpose built 'exit boxes' kick out sufficient light for the legend to be clearly illuminated, but don't actually cast much light onto the escape route, the only contribution being that some models illuminate the door and fasternings through slits in the bottom.
(http://www.regencyevents.com/photogallery/re854thumb.JPG)
(http://www.turbosquid.com/FullPreview/Index.cfm/ID/202281/SID/148607/blFP/1)

Some purpose designed makes are both illuminated signs and escape lighting (http://www.safetyshop.com/products/productDetail.asp?productcode=EW07A)

It's possible to have escape lighting EL & not need exit boxes, far less possible to have exit boxes without needing further escape lighting EL units.

A lot depends on the premises as to what you need - some bulidings I've dealt with have needed multistage addressable alarm and detection systems with hundreds of self contained EL's, whereas some have only needed torches and a rotary gong!

[Jim Creak]

My recommendation should be that lights should be treated as an illumination sources and signs are things that require illumination. Keep them seperate in your calculation and you will save money and energy ( Part of your Part L contribution) as you will probably find that signs are recieving adequate illumination from existing luminaires to be able to dispose of the light box completely. If you use Photoluminescent signs you will have belt and braces at a fraction of the cost little maintenance easy to check and no batteries or power use.

[Richard Earl]

hi jim

fully agree keep them apart this gives you better route information,  you are a good teacher thanks jim;)

[Ken Taylor]

Just to follow on from Anthony's clear explanation, I do like to see 'exit boxes' in rooms where activities frequently take place in very low lighting although not subject to licensing requirement - such as where plays, etc are performed in some school halls with stages and chapels but not considered to be public performances. It can also be worth designing for these where there is a good likelihood that the premises will require them in future as a licence condition. We did this recently with certain multi-use rooms in a new school sports centre.

[Pip]

Just to follow on from Anthony's clear explanation, I do like to see 'exit boxes' in rooms where activities frequently take place in very low lighting although not subject to licensing requirement - such as where plays, etc are performed in some school halls with stages and chapels but not considered to be public performances. It can also be worth designing for these where there is a good likelihood that the premises will require them in future as a licence condition. We did this recently with certain multi-use rooms in a new school sports centre.

Yes ken, I do the same-not only pre planning but in the case of activities in schools similar to a licensed premises i.e plays,disco's etc, helps to comply with the F.S.O.

[Jim Creak]

Again what you means is that you require signs to be illuminated. The British Standard requires all Escape route signs to be illuminated uniformly by a minimum 100 lux of fluorescent under normal conditions. The situation you describe should not occur.Fitting a light box in a non maintained condition does not answer your concerns. It only becomes conspicuous under mains failure this is not what you want. You require the sign to be illuminated at all times and I agree I also insist that the escape route is adequately illuminated as well, meaning the floor and door that is why keeping the luminaire seperate from the sign is far more effective and efficient.

[nearlythere]

The illumination of an exit sign can be provided by the normal lighting of the room or corridor. If you can see the sign at the lux level required, be it by artificial lighting or otherwise then it is illuminated. It can be illuminated by natural, artificial ie normal working lighting, or by emergency lighting in the case of the first two not being available.