NFPA 780 scope: what structures to protect

[radug]

Hello,

I have been asked if in a parabollic-through thermal solar plant, the solar field containing only parabollic-through collectors should be protected against lightning according to NFPA 780.

I am not familiar with USA regulations, it could be the first plant to be built there. I have just read NFPA 780-2011 and in its scope, it clearly says that electric generating plants are out of scope. I have only found IEEE 665 which specifically says something about lightning protection in generating plants.

However, although we intend to protect the power block of the plant against lightning and surges, protecting the whole solar field would be quite another thing.

So I am asking about interpretations, should the solar field be considered an ordinary structure? Could lightning protection be avoided (in terms of complying with regulations)?

I myself consider that the solar field should also be protected against lightning and surges, but as previously explained, have been asked to find a legal justification to avoid it.

 

[rbulsara]

Lighting protection is generally not a code requirement, but you may want to check your local codes. The insurance companies may have a say though. Also design criteria or client's expectation may require it.


Rafiq Bulsara

http://www.srengineersct.com

 

[DRWeig]

Yes, check local codes as Rafiq suggests. If no code (which is probably the case), you may want to just go through the NFPA 780 calculations and present them to your client to accept or decline as a basis for protection.

The legal requirement really boils down to managing risk. Who's liable if lightning causes a loss that could have been prevented?

Good on ya,

Goober Dave

 

[radug]

Thanks for the comments.

I think this issue is not correctly addressed in current standards.

I will do NFPA 780 calculations as a basis as you suggested.

In the other hand, I have not dealt with any insurance company issues. I was told by a DEHN representative about it, but at least in Spain, I have not heard about any specific cases.

Could someone provide with cases, specs or something similar from insurance companies in Europe or USA where they specifically ask for lightning protection?

 

[stevenal]

See IEEE 998. Not a regulation, but a guide.

 

[AusLee]

IEC 62305 comes in 5 parts and have a test you can do to evaluate if you need to protect the building or not regardless of applicable regulations.

It asks questions such as how frequently is the building used ,what is the heritage value, etc ... the result is either direct lighting protection is required (and to what level), or only indirect protection via surge arrestors or no protection required.