Lightning Protection

[nearlythere]

Anyone ever research this BS EN 62305 - Lightning Protection.

Are there any particular circumstances where the BS would consider the installation of lightning protection eg a certain building height, exposure, construction etc?
Does the BS contain a table of factors which ultimately leads one to recommend installation?

[lancsfirepro]

I like the way you say "this BS EN 62305".  Implies you are dangling it in front of you with a degree of disgust... as though you found a sweaty sock in your soup.  

Bit of info here - looks a bit techy mind...  http://www.atlas.org.uk/docs/bsen62305-simplified-risk-assessment-table.pdf

[longjohn]

So that's a simplified version! could be useful though. thanks. I guess as a fire risk assessor it depends on the building and to what lengths (or heighths!) one wants to take it. It is a section in PAS 79 to be assessed but if you are assessing a three story office surrounded by tower blocks it wouldn't be something to lose sleep over.

[kurnal]

In terms of lightning protection and fire risk assessments I tend to make a qualitative judgement similar to longjohn, with the following additional considerations-

if a building has lightning protection is it subject to an inspection and test regime?,
if it doesnt have lightning protection has an assessment been carried out?

But like longjohn I would be selective in asking these questions.

[DavyFire]

NT,
    A few years ago I did research the phenomenon of lightning strikes in buildings. I was carrying out FRA's and basically didn't know anything about lightning protection. I had a long chat with a local electrician who also designed, installed and inspected lightning protection systems. He gave me a lot of information including a few booklets on the subject. I then contacted Furse, which is a division of Thomas and Betts. I received a useful guide to BS EN 62305:2006
Interestingly different parts of the UK have varying degrees of lightning strikes. The centre of  England for example has a lightning flash density of 1.0 whereas N. Ireland ranges from 0.06 to 0.04 and parts of Scotland are as low as 0.02.
Assessing premises for the need for lightning protection is a specialised subject and there is a need to assess the lightning strike density, type of premises, relation to other buildings, etc.
Here is a link to the Furse website: http://www-public.tnb.com/eel/docs/furse/BS_EN_IEC_62305_standard_series.pdf
It is a useful site and at the end shows the guide to BS EN 62305:2006
If you are carrying FRA's solely for Life Safety as opposed to Property protection and business continuity then you do not need to consider lightning protection. As the author of PAS 79 says lightning protection is not necessary for the purposes of this fire risk assessment.
When serving with the good old fire brigade I did attend a detached house hit by lightning. The damage was collossal. Every conduit, socket and switch had been ripped through the plaster by the force.
You can then appreciate the power of mother nature.

[kurnal]

PAS79

If you are carrying FRA's solely for Life Safety as opposed to Property protection and business continuity then you do not need to consider lightning protection. As the author of PAS 79 says lightning protection is not necessary for the purposes of this fire risk assessment.
When serving with the good old fire brigade I did attend a detached house hit by lightning. The damage was collossal. Every conduit, socket and switch had been ripped through the plaster by the force.
You can then appreciate the power of mother nature.

I don't entirely agree with you there Davyfire. I would suggest that lightning is a fire hazard and indeed  the proforma and table C1 in the current PAS 79 does refer to it as a matter to be considered- ie if there is a system is it maintained?

 I once attended a care home that had been struck by lightning. One chimney was partly demolished, there was a significant fire in the roofspace and 14 minor seats of fire (most self extinguished to be fair) throughout the building. All electrical systems including the fire alarm ruined.   No chance of PHE that day!

[Mike Buckley]

I agree with you Kurnal, my take on its inclusion in PAS 79 is that the first question is simply a matter of fact: does the building have lightning protection or not? If it does, is it tested?

I have never looked at this as having to recommend the installation of lightning protection unless it is very obvious. I did suggest it at one site however the circumstances were that a neighbouring higher building did have lightning protection but it was being demolished, which left the building I was assessing as the tallest in the area!

Besides that the lightning conductor is designed to attract lightning and provide it with a safe path to earth, therefore if lighting protection is installed the building is more likely to be struck, hence it would be a very good idea to ensure that the system works.

One assessment I did I found a factory chimney with a lightning conductor which finished 6 ft above the ground as smeone had nicked the remaining copper!

Should we be recommending lightning protection in general no, unless it is an obvious problem, in which case, advise the client should seek a proper assessment by a competent person.

[nearlythere]

Thanks for all the interesting info about lightning protection. Nothing is ever simple is it?

[DavyFire]

Kurnal,
         Perhaps I didn't make myself clear. If a lightning conductor is installed, I would ask for confirmation of inspections and testing. If one wasn't installed in the first place, then I wouldn't require one solely for life safety FRA's. Especially in N. Ireland where we are fortunately less liable to lightning strikes. But doesn't mean it will never happen.

[kurnal]

I agree and dont pretend to have anything other than a rudimentary understanding of the topic though having witnessed the energey of a strike at first hand find it fascinating.

That said I would never recommend a lightning protection system should be installed as part of a life safety risk assessment but if a building does appear to be at risk I would recommend an assessment be carried out in accordance with BS EN 62305 by a competent person.

Someone nicked the copper Mike? Its usually coppers that nick me......