Lightning Protection for a building with Metallic Roof

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tarekbadr

Member
There is a steel structure building with Alum. Clading and metallic Roof (47m*22m and its hight is about 9m ) ,My Question is : lightning protection system is required or not for this building , Please advise
 

bphgravity

Senior Member
Location
Florida
Requirements for lightning protection are typcially based on occupancy type, not construction type. While the roofing type changes the dynamics of the system and installation, it does not determine if protection is required or not.

In the event a LPS is not required for this building, the owner has the option to perform a risk assessment to determine if a LPS is suggested and/or practical based on a full evaluation of all issues and conditions.

The US standard for lighting protection is the NFPA 780.
 

tarekbadr

Member
If LPS is required for this building , can we use the metallic roof instade of copper tape mish on roof , then connect it to the steel structure up to earth rod?
 

hurk27

Senior Member
If the metal cladding is bolted or bonded by bolts to a metal structured frame, then you have a great Faraday cage to start with, just add some ground rods around the perimeter or the building and bond them to the building. of course keeping all entry and exit conductors to a single point, will help keep lightning from entering in on any of these circuits. like power, communication, and control conductors, make sure they are properly bonded on the outside and you should be good to go.

Of course this is my opinion and it would be a good idea to have a risk assessment done as sitting here I can't see every thing, but I'm just saying you have a good start with a all metal building.
 
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If LPS is required for this building , can we use the metallic roof instade of copper tape mish on roof , then connect it to the steel structure up to earth rod?

By US standards, NO. You cannot use the metal skin as a strike terminal unless it is 3/16" thick. If it is not then you must provide air terminals as required by the slope of the roof and ground as required.

I'm not that familar with European standards and the tape method.
 

bphgravity

Senior Member
Location
Florida
Bryan
Does Florida have specific requirements for lightning protection?


Yes, the Florida Building Code identifies 3 occupancy types that require a lightning protection system in compliance with the NFPA 780. Hospitals, Nursing Homes, and Educational Facilities.

Most new governmental structures will have a LPS such as fire / police stations, community centers, libraries, city hall, etc., as a mtter of good design, insurance discounts, and sometimes FEMA compliance when used as a shelter or emergency operations center.

You would think the state of Florida would be flooded with lightning protection companies, but in reality, the demand is still huge and there are really not too many out there with the expertise and exclusive focus on this segment of the industry.
 
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