Lifts - To fail or not to fail

[KevinD]

Dear All, this is my first post so hello to you all firstly!

My question relates to lift safety and I would like to pose this to the forum:

If a lift, which isn't specified for use in an evacuation, is used to transport people to upper floors, should it fail to ground and if so is this required/documented anywhere?  I'm asking this as though lifts often state don't use in the event of a fire, this doesn't reflect the fact that somewbody could be using and become trapped in a lift when a power failure occurs, potentially due to the fire itself e.g. power failure from fire knocking out power supply.

Also, what is your general experience as to what people do once identifying this as a risk.  Do they modify lifts to fail to ground or continue to use them as they are?  I appreciate there should be some means of releasing people (e.g. hand winching) but in an emergency scenario this may not always be quick or safe to effect.

Your thoughts on this would be very welcome.

Regards,

Kev

[AnthonyB]

There is nothing to say every non firefighting lift must go to ground, although it is popular in many buildings to prevent use.

One thing to consider is where 'ground' is - is it a sterile lobby direct to final exit or is there a likelihood that it opens into a risk area, as you don't want someone in the lift at the time of fire trapped in a blazing ground floor lobby unable to shut the doors and go back up a floor. Not impossible to happen.

The training and liability issues plus a reduction in the provision of house/building managers means very few buildings can release people without external assistance - a lot have replaced local alarms with REM communication systems so trapped people are put through to a lift company monitoring station who will either send a lift engineer or if required the FRS.

Personally in most of the buildings with limited public access I'm happy with signage and good staff training, wardens and drills. If you are in the lift the second the alarm starts and the building power also drops off then it's difficult- but how likely is this?

[KevinD]

Thanks very much Anthony for your reply.  I was hoping to talk through my concerns a bit further.

Your last sentence posing the question of likelihood is the one that causes me the problems.  The likelihood of being in a lift during a fire and power loss I would agree is low but how low and whether this is a tolerable risk is my concern.  

From a risk assessment point of view, in terms of it being a forseeable risk I would suggest it is (e.g. fire begins, damages wiring and knocks out power) though albeit the likelihood of this happening while somebody is in the lift is low as you say.    

Again, as you say, engineer is called out due to issues with releasing the passengers (possible training etc is an issue to be further explored I accept).  In the twenty minutes (estimate) or so the engineer takes to turn up the fire/smoke develops with the passenger still trapped in the lift, potentially restricting the ability for the engineer to effect a release by threatening the area where engineer operates from.  

So, on the risk assessment basis, the likelihood is low but the potential severity is high.  I can't help but feel that from an emergency procedure point of view, it is one that should be planned for and that where the lift can fail to ground in a sterile environment then this modification should be considered.

To help quantify the likelihood, do you know of any statistical information on the number of fires affecting power supplies or just an impression from your experience of whether this often happens?  

Many thanks again,
Kev

[kurnal]

You need to look at the supply to the lift and consider how likley it is that a fire in the building could affect the supply to the lift.
In many buildings even pre building regulations the lift had to have an independent feed taken from a spur direct from the meter- look at  the routing of the cable and make a judgement. Usually the lift has a seperate spply and cables are protected- even if only by being routed up the protected shaft of a lift or staircase.
See also BSEN 81.

I go with Anthony on the signs and training - if you do wish it to be interfaced to the alarm you have to be certain that it will only take people to an area you can guarantee will be safe from fire

[KevinD]

Hello Kurnal,
Thanks for the additional advice, this sounds like a job for the electrician!

It does make me wonder though why the effect of a power failure of the lift in emergency situations doesn't appear to be well covered either in British Standards or fire safty guidance.  Maybe this is because risks are low or it could be because as many of you have said fail to ground isn't always the best option.  I've hunted for ages though and can find very little even in reference to this as a consideration.

I appreciate risk assessment is key and in speccing/designing the lift properly at the design stage but I can't help but feel there would be a lot of building managers who wouldn't have the faintest idea how secure the power supply to their non-evacuation lift is in the event of an elctrical fire, or whether they could release any trapped occupants quickly were this to happen.