Effect of Lightning Strikes on a Building

[Tim]

Good evening guys,

I have just had a call to go and have a look at a hotel tomorrow that was hit by lightning yesterday morning. All i know is that its a 2 story building and was hit and now has a hole in the roof and that there is no lightning protection system in place.

They are worried that the strike may have damaged the electrics in the building and therefore voided their insurance. I have no experiance with lighting protection systems or the effects of a lightning strike on a building, I'm hoping someone on here has some insight on the main things to check. I will be recommending that they have the site assessed for an LPS by a specialist contractor as this is not something I or anyone in the company i am working for is competent to do.

My plan is as follows:
Go to site, ask the manager that was on duty at the time what happened and if anything went down/caught fire/made funny noises etc.
Then check out a sample of RCBO's/RCD to ensure the electronics in them were not damaged by the EMP.
Check Bonding and Earthing conductors and clamps for signs of overheating.
Do the usual Ze and Pfc test to check the main earthing conductor has not been damaged.

Can anyone suggest anything else that would likely have been damaged by a strike? I am working on the assumption that the strike hit some metal work on the roof (AC unit??) that was connected to the MET and that was the route to earth for the strike.

Any advice would be appreciated as this is not one of the things you come up against on a daily basis. And of course i will post up pictures when i get to site.

Cheers,
Tim

 

[Darkwood]

Due the the massive voltage and current along side the massive magnetic fields generated by a lightning strike the install will require a 100% EICR, the main strike comes with many spurring less intense fault paths that may run through circuits that seem to be away from the main damage and will only show up in ELI tests and Insulation Testing.

Ive seen lightning strike to a church blow out the full length ring main of buried pyro cleanly out off the wall leaving a nice chase and plaster on the floor...the pyro was undamaged but it blew out due to an induce EMF as the lightning went through the building not because it was part of the path it tried changing shape in a split second with the induce magnetic field and whip-lashed itself out of the wall.

 

[Tim]

Due the the massive voltage and current along side the massive magnetic fields generated by a lightning strike the install will require a 100% EICR, the main strike comes with many spurring less intense fault paths that may run through circuits that seem to be away from the main damage and will only show up in ELI tests and Insulation Testing.

I hadnt thought of that, i was imagining that all the damage would be around one area, the spurring strikes didn't even cross my mind.

I have been allotted 2 days to check out the building, this wont be enough time to do a 100% eicr, but my purpose on site is to let them know what should be done after seeing the extent of the damage, so a 100% eicr is defiantly on the cards as a recommendation.

Cheers, Tim

 

[SirKit Breaker]

Last lightning strike i looked at needed a full rewire, and the insurance paid for it. Failed IR tests, damaged CPC's and melted sleeving in CU. I think it was the lightning strike that pushed a poor installation over the edge though, not just damaged due to the lightning strike. i would look at the meter as well, it may need replacing with one that will withstand Cat 2 impulse voltage.

Cheers............Howard

 

[Darkwood]

As its and hotel you may be able to do a progressive test where you start on all circuit local to point of strike and work away from that point until your reading are all clear, a previous test report would be good to understand the condition and readings that had been tested in the past ....lightning is so random and varies so much one strike can show cosmetic damage to building only and the next can totally take out the electrical system.... it all down to where the leader stroke paths went ..whether multiple paths were realised and has induced current damaged any sensitive equipment or circuits... Check all rcd's fully function as a priority this may be the life saver as you build your report.

 

[Farmelectrics]

Ill bet there insurance is void anyway with out the lighting protection

 

[Darkwood]

I got told once insurance void due to act of god.... a while back... i legally challenged the to prove that god exists or oblige the claim.... they backed down and payed then reworded all of their insurance policies... they said it was a recognised term i just said im an athiest and so i don't recognise it and questioned their legal teams professional stance for using a religious clause as an exemption within a insurance policy..... no comment lol :wink5:

 

[Silly Sausage]

Hahaha...nice one!
No way Jesus came from your loins either.

 

[Darkwood]

Hahaha...nice one!
No way Jesus came from your loins either.

Very apt profile pic lol

 

[Tim]

As its and hotel you may be able to do a progressive test where you start on all circuit local to point of strike and work away from that point until your reading are all clear, a previous test report would be good to understand the condition and readings that had been tested in the past ....lightning is so random and varies so much one strike can show cosmetic damage to building only and the next can totally take out the electrical system.... it all down to where the leader stroke paths went ..whether multiple paths were realised and has induced current damaged any sensitive equipment or circuits... Check all rcd's fully function as a priority this may be the life saver as you build your report.

That sounds like a proper plan, ill start at the strike point and work out from there.

Cheers for the replys guys, ill be back tomorrow with pics

Tim

 

[GLENNSPARK]

Due the the massive voltage and current along side the massive magnetic fields generated by a lightning strike the install will require a 100% EICR, the main strike comes with many spurring less intense fault paths that may run through circuits that seem to be away from the main damage and will only show up in ELI tests and Insulation Testing.

Ive seen lightning strike to a church blow out the full length ring main of buried pyro cleanly out off the wall leaving a nice chase and plaster on the floor...the pyro was undamaged but it blew out due to an induce EMF as the lightning went through the building not because it was part of the path it tried changing shape in a split second with the induce magnetic field and whip-lashed itself out of the wall.

too bloody rite it will

 

[Engineer54]

Ill bet there insurance is void anyway with out the lighting protection

That would depend on whether or not the building came within the recommended criteria of needing/requiring a lightning protection system.

 

[GLENNSPARK]

I got told once insurance void due to act of god.... a while back... i legally challenged the to prove that god exists or oblige the claim.... they backed down and payed then reworded all of their insurance policies... they said it was a recognised term i just said im an athiest and so i don't recognise it and questioned their legal teams professional stance for using a religious clause as an exemption within a insurance policy..... no comment lol :wink5:

bloody farce innit....

 

[GLENNSPARK]

That would depend on whether or not the building came within the recommended criteria of needing/requiring a lightning protection system.

what?...if it were an act of god?...
what if it were a mosque?

 

[Darkwood]

The church i worked on had had its lightning line pinched by copper thieves but like any religion there building normally have a spire or symbol of some sorts but also due to the obvious attraction for lightning they are fully protected..

What makes me laugh is if they didn't use science/physics to protect their building they have a high chance of been struck .... now as its claimed as an act of god surely he wouldn't attack his own places of worship......food for thought