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Topic Title: High Risk Emergency Lighting Help
Topic Summary: To determine if an Area is classed as high Risk
Created On: 16 November 2012 02:02 PM
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 16 November 2012 02:02 PM
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Mattysmith1983

Posts: 80
Joined: 25 July 2008

How do you determine if an area is high risk and requires 10% of the maintained (normal) illuminance. Is this via risk assessment?

My reason for asking the question is that i'm looking at a scheme which involves a distillery for Gin. Now the area is classed as a Zone 1 Atex space but this is purely because the danger in the flammable content of the air due to the alcohol. The area itself contains no moving machinery or any further risks to human life. So is this space classed as high risk due to the nature of the air or can this be classed as open space with escapes routes where 1 Lux is required.

I would be interested in your thoughts.

Many thanks

Matt
 16 November 2012 02:46 PM
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Avatar for OMS.
OMS

Posts: 19747
Joined: 23 March 2004

High risk tasks by definition:

high risk task area lighting
that part of emergency escape lighting that provides illumination for the safety of people involved in a potentially dangerous process or situation and to enable proper shut down procedures for the safety of
the operator and other occupants of the premises

also

4.4 High risk task area lighting

4.4.1 In areas of high risk the maintained illuminance
on the reference plane shall be not less than 10 % of
the required maintained illuminance for that task,
however it shall be not less than 15 lx. It shall be free
of harmful stroboscopic effects.

4.4.2 The uniformity of the high risk task area lighting
illuminance shall be not less than 0,1.


Personally speaking, i wouldn't say that walking through or escaping from the space was a high risk task despite the environment. You don't need to do anything other than get out. Obviously your client will advise the outcome of his risk assessment. Depending on the size I'd go with an anti panic area with a minimum of 0.5 lux overall.

If it's ATEX Zone 1 you might just have a problem with integral batteries though - it's quite probable that with conversion of the ATEX general luminaires (or operation from a battery and invertor outside the zone) you'll get above 15 lux anyway.

Be careful of the ATEX elements if you are unfamiliar with them

Regards

OMS

-------------------------
Failure is always an option
 16 November 2012 02:58 PM
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MHK

Posts: 19
Joined: 29 July 2011

The risks associated with an installation are usually identified within the the risk assessment, however, in the absense of one (which is often the case) take a sensible engineering judgement.

High risk areas are those which would present significant risk to persons i.e. extensive moving machinary, vats contaiming acids / chemical baths, swimming pools etc.

The situation you discribe doesn't sound particularly hazardous, thus a combination of emergency escape lighting and antipanic lighting may be appropriate.

In terms of the luminaires and terminations themselves emergency luminaires would also need to the ATEX rated if there is a potential risk of explosion.

Hope that helps.

MHK
 16 November 2012 03:08 PM
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Mattysmith1983

Posts: 80
Joined: 25 July 2008

Thanks for the responses.

The Atex fittings will adopt an integral PL lamp and battery back up, the problem i have is that if every luminaires within the space incorporates this i achieve 15 Lux, however the space achieves an overall 300 lux value for general lighting so for hazardous areas i would need to a achieve 10% of this which would be 30 Lux. I just cant achieve this.

So shall i just settle at 15 Lux or do i say that 0.5 Lux is acceptable. Other than the flammable atmosphere there it no risk to human life.
 16 November 2012 03:22 PM
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Avatar for OMS.
OMS

Posts: 19747
Joined: 23 March 2004

Well, if you are using integral conversions then you are fixed to a layout by the general lighting aren't you

There are uniformity requirements for emergency lighting that you'll need to meet (Normally 40:1, max to min) which will tend to set the spacing of the emergency luminaires

from this you wil probably end up with every second or every third fitting being an emergency to meet say a target of 1.0 lux minimum

regards

OMS

-------------------------
Failure is always an option
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