Lightning coductors

[Paul2886]

Hi all, Have any of you FRA's been asked to include the testing of lightning conductors in the report. Just had a client that has ask the procedures for this. Have to admit this is the first time this has arisen with me. Any advice on testing would be appreciated and of course how you include this in the report. It is just the requirement to administer the help of a competant tester as I know there are a variety of tests besides visual. Thanks

[patrickhamblin]

Lightning protection is a specialist subject and covered by a suite of Standards under the number BS EN 62305:2006, which is in four parts. Even the maintenance requirements are less straightforward than under the previous British Standard, with there now being different requirements depending on protection levels (BS EN 62305-3).
It is suggested contact is made with a specialist and there is a trade association for these specialists known as 'ATLAS' (Association of Technical Lightning and Access Specialists - previously known as National Federation of Master Steeplejacks and Lightning Conductor Engineers) - they have a Website.

[Chris Houston]

our lot always ask this, it is a cause of fire. Although I must admit to not being familiar with this new standard and had (until today) been asking for annual tests by a competent person. Don't think a fire safety risk assessor needs to be a lightning expert just ask that systems be tested by experts.

[Martin]

(3)   Lightning Strike

The building is provided with a lightning conductor.

Action Required

Confirmation of appropriate maintenance of the lightning conductor is required (BS 6651 – 1999 is the relevant British Standard).

Above is my RA for our buildings with lightning conductors. (I must update to BS EN 62305:2006 at review)  My RA is not very detailed but if we are following relevant BS I am not too worried. I vaguely recollect the inspection interval was 11 months meaning over a period of time the conductor would be seen in different weather/seasons. Our buildings are normal high rise flats and occassional school tower block. Nothing with "extra" ignition/fuel risk.

[wee brian]

what do you do for buildings that don't have a conductor?

[Chris Houston]

There was a methodology contained within the BS to determine if it was necessary, but it is too complex for this sort of situation.  I determine if there is any history of lightning strikes, compare the height of the building to the surrounding buildings, trees, objects.  I've never had to recomend it for a FRA as I tend to do them on low rise buildings, but do occassionaly recomend it for insurance purposes if they are the tallest thing in the area.

[wee brian]

does lightning strike twice??? If there is a history of ligtning trikes then;

a) will there ever be another one?

b) if the building didnt burn down last time then it must be OK???

I suppose this is a legit FRA issue - or is it?

[Mar62]

It is one of the things I cover in my assessments as most of my work tends to be in central london (not an expert on lightning systems). I simply cover the topic, look to see if one is visible and condition if possible to see clearly or if records exist and if its maintained properly. In the past I have found a lot of systems not being maintained, corroded or broken conductors, missing fittings etc. I have never used this but the link below is of a program that can apparently be used to determine the risk of a structure being struck.

http://www.furse.com/elp/risk.asp

[AnthonyB]

Traditionally we've always looked for at least 12 monthly test certificates for lightning conductors, or the retest interval specified by the maintenance engineers whichever is the shorter.

As important we check to see if the installation passed and if not that it has been repaired and retested - more than once have I been shown a stack of test certificates with the un-repaired installation failing each year.

Where no conductor is fitted we look at the surroundings and if it seems odd that it doesn't have one we delve further and request specialist assessment, especially if an existing building of some years has had loads of new things stuck on like air con, mobile phone masts, etc

[Chris Houston]

does lightning strike twice??? If there is a history of ligtning trikes then;

a) will there ever be another one?

b) if the building didnt burn down last time then it must be OK???

I suppose this is a legit FRA issue - or is it?

I can offer no evidence to support this theory, I am just going along with the accepted wisdom of what I was trained as an insurance surveyor, but a lightning does strike twice and one hit should be taken as a warning that more might follow.

Lightning strikes tend to result in moderate damage to electrical systems, CCTV and the like, but they can start a fire.  Just because it only damaged a CCTV system first time round doesn't mean it won't cause a fire second time round.

That said, it is not a common cause of fires in my own experience.

[jokar]

I think it is one of the things that was being sold as part of PAS 79.