Before we start, it's critical to get one thing clear. To properly comply with emergency lighting regulations you, the Responsible Person, must conduct a full and proper fire risk assessment and act on the findings.
The rule of thumb test is just that. We shouldn't really need to say this, but to prevent anyone getting the wrong end of the stick, here's the Wikipedia definition:
a principle with broad application that is not intended to be strictly accurate or reliable for every situation. It is an easily learned and easily applied procedure for approximately calculating or recalling some value, or for making some determination
The test I'm about to describe is not sufficient to replace your Fire Risk Assessment! With that out of the way, on to the rule of thumb for testing if your emergency lighting is adequate:
Rule of thumb: when the building is empty at night, isolate the mains electrical intake. Check if there is sufficient light to find your way out of the building safely or not. If not you need emergency lighting, PERIOD!
It's common sense, in
Imagine an emergency scenario, the fire alarm is ringing, there's smoke, the power fails and everyone wants to leave the building. The room you are in is plunged into darkness. The situation is stressful enough without people struggling to find their way out.
It's one thing if you're familiar with the building layout. But... what if you are visiting the premises for the first time? If the building is not lit you could easily struggle to escape and the consequences would be dire.
Emergency lighting requirements insist you illuminate the escape route. That's what it is there for and that is what it must do in an emergency.
This emergency lighting test is usually moot because building regulations stipulate emergency lighting as a requirement in non-domestic buildings. We do, however, regularly encounter arguments against the need for a full design and installation.
The confusion often stems from out of hours use. For example, Schools will often argue that because the children leave at 3.30pm there's no need for emergency lighting, the risk is simply not there, they plead. Besides, if there is borrowed light from outside to illuminate inside the premises, the relevant person could escape safely.
Years ago the 'not used out of hours' excuse was plausible but not now...
Whilst use may be occasional - which of course lowers the risk - the vulnerability of large groups of adults or children make emergency lighting essential for educational premises.
And that's without considering the cleaners, teachers and assistants working late (or early) and perhaps maintenance staff/contractors - all of which are relevant persons.
While an ill-informed secretary may have ticked not required on the Fire Risk Assessment because the kids go home before the hours of darkness, it's an error. Your Fire Safety Inspector will not buy it.
Accepting emergency lighting is required, schools will try to get the best deal, understandably. But the cheapest option is often the wrong option because while your electrician is qualified, it is extremely unlikely that he is conversant with emergency lighting regulations.
For example, designing an emergency lighting system requires taking into account the colour of the flooring and walls. Dark wall colours and carpet don't reflect light while laminate does. This and other factors need to be accounted for in the design calculations. Electricians do not know this.
Of course, that is specialist knowledge but, we hear you ask, surely an electrician can fit the emergency lighting?
Well not really...
While the fitting of lights safely is right
To quickly test if your emergency lighting system is up to scratch, use the rule of thumb test again. Put yourself in the shoes of a
Rule of thumb: when the building is empty at night, isolate the mains electrical intake. The emergency lighting will come on, if you can get out safely you have enough - if not you need more!