Lightning protection

[imago]

As it's not related to commercial or industrial specifically I thought I'd ask in here.

The work being done is two facing external walls being removed and the offices being made into one by removing the gap between them. Blockwork construction with a steel frame, single storey. Oh and it's a primary school. The down conductor for the lightning protection runs down the face of one wall to an earth pit about 0.5m from the base of the wall.

When the wall comes down the choices(regs and recommendations aside for a moment) will be to either extend the conductor and dig in a new pit, or have the conductor and pit inside the new office. The second choice seems a bad one to me, but that's based on noting more than not liking the sound of the idea. I have no idea if it currently meets a standard, or indeed if the building requires LPS.

I won't be doing anything with the LPS as I don't have experience or knowledge with them. What I will need to do is provide some information as to what will need doing so that I can justify getting in a specialist. So what're the basics with this? Assuming it needs moving is there a particular sign off to be done for BS62305 is the LPS is worked on? Can it run internally? Will it need bonding to building structure elsewhere? Should it have an inspection periodically anyway?

Oh, and any recommendations for a company which does this sort of work in/near Birmingham?

 

[Hants-Spark]

To be honest I know very little with regards to LPS but the idea of running the conductor inside also doesn't sound right to me. I think the fact that there are plenty of specialist firms who do deal with this sort of work and also you yourself have limited knowledge warrents calling in the specialists from the start and getting all the correct information to work with from the off. Check google, I'm sure there will be several firms in and around the area.

 

[Guest55]

lightning rod conductors run inside the building ?
i can see a small flaw in this plan lol.

and the church im working on has the pit rods connected to the met with a rather hefty conductor.
E54 is your best bet for more insights into this issue.

 

[somersetsparks]

lightning rod conductors run inside the building ?
i can see a small flaw in this plan lol.

and the church im working on has the pit rods connected to the met with a rather hefty conductor.
E54 is your best bet for more insights into this issue.

Looks like the OP will have to wait for the morning gong to sound in China

 

[imago]

I think the fact that there are plenty of specialist firms who do deal with this sort of work and also you yourself have limited knowledge warrents calling in the specialists from the start and getting all the correct information to work with from the off.

Quite right, but I would like to give them some explanation as to why a specialist company needs to be called in.

 

[MDJ]

Oh, and any recommendations for a company which does this sort of work in/near Birmingham?

Omega of Nottingham are a good company, I have used them, several times

 

[imago]

E54 is your best bet for more insights into this issue.

Hmm, will you ask him for me? I may have pi55ed him off a bit as we both saddled up our tallest mounts and refused to give way.

 

[Hants-Spark]

Quite right, but I would like to give them some explanation as to why a specialist company needs to be called in.

As I've mentioned I have very little knowledge on this subject but if memeory serves me right there are calculations that need to be carried out to ensure you have enough rods etc for the size of the building, this on its own justifys bringing the specialist in, in my opinion, i wouldn't want anythig going wrong on my conscience.

 

[imago]

Yeah, that's a big part of it as far as I'm concerned. Clearly work has to be carried out on it, but I would think it should be checked out before work starts to make sure that it's up to the job to start with. Then any changes made to it are acceptable and up to standard, and finally that it's certified so that it satisfies the insurance company and the landlord who I presume is the Local Authority.

 

[Outspoken]

Omega Red (as MDJ stated) are excellent contractors who will give good service, if you do not need any protection they will tell you. Most single story buildings do not require protection, but the surrounding environment dictates which do and which do not.

Lightning protection must, by law, comply with the requirements of BS 6651:1999 and BS 62305: 2006. There is a legally required RA that must be completed for an installation, Omega reds version can be seen HERE

If you require independent advice ahead of contacting a contractor then I would suggest you speak to ATLAS (The Association of Technical and Lightning Access Specialists)

I have this as a reference link for when I did some work in Schools, although it's Torbay Council Policy, it is pretty much the same all over the UK so gives you a good idea of the standards expected, you can see this HERE

For general reference here is some outline of the basic requirements that must be considered or complied with;

• BS EN 62305-1:2006 provides the general principles to be followed in the protection of structures against lightning, including their installations and contents as well as people.
• BS EN 62305-2:2006 is applicable to risk assessment for a structure due to lightning flashes. Its purpose is to provide a procedure for the evaluation of such a risk.
• BS EN 62305-3:2006 provides the requirements for protection of a structure against physical damage by means of a lightning protection system (LPS), and for protection against injury to living beings due to touch and step voltages in the vicinity of an LPS.
• BS EN 62305-4:2006 provides information for the design, installation and maintenance of lightning electromagnetic impulse (LEMP) protection measures for electrical and electronic systems within structures, able to reduce the risk of permanent failures due to LEMP.
• BS EN 62305:2006 lightning protection systems comprise external (structural) and internal (surge protection etc.) components, where previous standards did not. It is now recognised that the electromagnetic effects of lightning related activity, and switching events, are the cause of much damage to systems and equipment, with the subsequent loss of critical data.
• Surge protection devices (SPDs) were not required previously to comply with older standards. SPDs are required under BS EN 62305:2006; they are part of the internal LPS and are installed firstly to prevent dangerous lightning currents from entering a building via its services, and secondly to reduce the risk of damage to electrical and electronic equipment and critical systems from transient over-voltages.

I hope this information is helpful to you.

 

[imago]

Half of each glass block wall will be removed, along with the white rendered walls behind them. You can see the down conductor just to the left of the steel column in the centre of the picture. The pit is just to the right of the same column.

 

[Outspoken]

If the wall behind that has the ADT alarm mounted on it is to stay then you could likely go onto the roof and simply redirect the current conductor and utilise the existing pit with a little work, but I seem to recall something in the Regs about the conductor being mounted on flammable materials, and the top of the wall is clearly clad in wood.

I would certainly suggest you get in an expert, this not only make you look professional, but it gets the job done properly and quickly, gives you peace of mind and a completion/test certificate that is also professional. The other side of it is that if something did go wrong you have legal protection because you used a certified contractor for the work.

 

[Brightspark2]

What determines a building needing lightening protection?...

Im guessing height is the main factor but ive seen 3 storey buildings with it...

 

[Outspoken]

What determines a building needing lightening protection?...

Im guessing height is the main factor but ive seen 3 storey buildings with it...

Location, location, location. That is the whole point behind the RA being done to assess the risk the building has to lightning strikes. A single story structure surrounded by taller buildings is under minimal if any risk and likely would not require any, but a single story structure in the middle of a field would be at seriously increased risk of a strike if it was actually the tallest structure about.

The material the structure is made from is also important, concrete structures are less susceptible than wooden or metal structures, however most buildings have steel of some description on the roof and thus their vulnerability increases as a result.

 

[Brightspark2]

Location, location, location. That is the whole point behind the RA being done to assess the risk the building has to lightning strikes. A single story structure surrounded by taller buildings is under minimal if any risk and likely would not require any, but a single story structure in the middle of a field would be at seriously increased risk of a strike if it was actually the tallest structure about.

The material the structure is made from is also important, concrete structures are less susceptible than wooden or metal structures, however most buildings have steel of some description on the roof and thus their vulnerability increases as a result.

I see, very interesting..

 

[Engineer54]

As it's not related to commercial or industrial specifically I thought I'd ask in here.

The work being done is two facing external walls being removed and the offices being made into one by removing the gap between them. Blockwork construction with a steel frame, single storey. Oh and it's a primary school. The down conductor for the lightning protection runs down the face of one wall to an earth pit about 0.5m from the base of the wall.

When the wall comes down the choices(regs and recommendations aside for a moment) will be to either extend the conductor and dig in a new pit, or have the conductor and pit inside the new office. The second choice seems a bad one to me, but that's based on noting more than not liking the sound of the idea. I have no idea if it currently meets a standard, or indeed if the building requires LPS.

I won't be doing anything with the LPS as I don't have experience or knowledge with them. What I will need to do is provide some information as to what will need doing so that I can justify getting in a specialist. So what're the basics with this? Assuming it needs moving is there a particular sign off to be done for BS62305 is the LPS is worked on? Can it run internally? Will it need bonding to building structure elsewhere? Should it have an inspection periodically anyway?

Oh, and any recommendations for a company which does this sort of work in/near Birmingham?

Before anything else i say, i don't hold any grudges against you, or anyone else come to that, that i have a disagreement with, on any of the threads...

Basically the existing down conductor would need completely removing, and the air conductor on the roof modifying to suit the new external contours of the building. There should be a down conductor every 10m around the building each with a removable test point (depending on the connection to the earthing rods/electrodes used on the system) If the LP system hasn't been tested for some time, now would be a good time to bring in a specialist company to survey the existing system carry out any modification work and finally certify the installation. Ensure this LP system is bonded to the main incoming service MET....

As some have stated, internal down conductors is not the way to go here, but in certain circumstances internal steelwork, say in church bell towers and castle towers will need to be directly connected to the LP system internally. Also re-bar reinforcement and steel frames of buildings can be used in certain circumstances as down conductors, but i think i'm digressing away from your particular query now!! lol!!

 

[imago]

Cheers gents, I've forwarded details of Omega and Furse to them. I've pointed out that there's a fair bit involved in this and that the first step should be a proper assessment, followed by qualified recommendations.

 

[Outspoken]

If you would like to download a very useful guide to Lightning protection I have uploaded one to my dropbox folder, you can download it HERE