Ground Ring for lightining system

[faresos]

Is a ground ring for lightning system always required for new construction buildings? I'm working on a project that will required Lightning system, someone told me that ground ring is not required if the building has a steel structure. I could not find this requirement in NFPA 780. Any thoughts will appreciated.

 

[ZoneOfProtection]

Look at 4.20.1.2 (NFPA 2008) - structures over 18m (60') are required to have a ground loop.

Intermediate loops 4.20.3(A) are not required for steel framed structures.

Don't forget if you are using the steel as the downleads that the steel columns are grounded on 60' average spacing not 100' spacing that is required for cable downleads.

I hope I haven't confused the issue.

 

[faresos]

Thanks for the info, that was very helpful! I used to provide ground rings for all buildings with steel structure and less than 60' tall. I'm sure there is a good saving money by deleting the ground ring.

 

[weressl]

Thanks for the info, that was very helpful! I used to provide ground rings for all buildings with steel structure and less than 60' tall. I'm sure there is a good saving money by deleting the ground ring.

The function of the ring is to provide equalizing connection between the electrodes in order to help directing the current flow to a desired location during discharge. When you use the building steel, it performs the same function. Depends on the structure and the type of strike it could be advantageous over single downleads as it would help to spread the manetic flux and RFI emission, so it could reduce the influencing effect on the electrical/electronic equipment within the structure.