Lightning protection

[Ainsley Whyte]

What does the code says about lightening protection for oil refinery ? Can you say it is a breach not to protect against lightening strike from hitting your plant especially the oil plant.

 

[ron]

There is no national code that requires lightning protection that I'm aware of.
There is a hazard analysis in NFPA 780 you can perform to determine whether it is recommended.

 

[charlie b]

I agree with Ron. The "Lightning Risk Analysis" (LRA) to which he refers essentially looks at two things: (1) How likely is it that lightning will strike the structure? and (2) How serious would it be if lightning did strike the structure?

For item (1), the LRA has you consider how often lightning strikes occur in that area of the country. There is a map that shows strike frequency. You also consider the shape of the building (i.e., tall buildings get hit more often that short ones) and what else is in the area (i.e., lightning is less likely to strike your building if there are taller buildings or tall trees nearby).

For item (2), the LRA has you consider what is inside the building, and rate its importance. For example, a lightning strike on an elementary school, a gas station, or a hospital might be more of a concern than one on a restaurant, a bookstore, or a car repair shop.

The process has you calculate and compare two numbers. Depending on which of the two is larger, the LRA results say either that lightning protection is recommended or that it is not warranted. It does not say that one is "required," as Ron mentioned.

 

[Ainsley Whyte]

I agree with Ron. The "Lightning Risk Analysis" (LRA) to which he refers essentially looks at two things: (1) How likely is it that lightning will strike the structure? and (2) How serious would it be if lightning did strike the structure?

For item (1), the LRA has you consider how often lightning strikes occur in that area of the country. There is a map that shows strike frequency. You also consider the shape of the building (i.e., tall buildings get hit more often that short ones) and what else is in the area (i.e., lightning is less likely to strike your building if there are taller buildings or tall trees nearby).

For item (2), the LRA has you consider what is inside the building, and rate its importance. For example, a lightning strike on an elementary school, a gas station, or a hospital might be more of a concern than one on a restaurant, a bookstore, or a car repair shop.

The process has you calculate and compare two numbers. Depending on which of the two is larger, the LRA results say either that lightning protection is recommended or that it is not warranted. It does not say that one is "required," as Ron mentioned.

Agree my friend

 

[David Svennigsen]

There is no national code that requires lightning protection that I'm aware of.
There is a hazard analysis in NFPA 780 you can perform to determine whether it is recommended.

Thanks, Ron for help because I've also the same problem.

 

[don_resqcapt19]

Even where lighting protection is required, the construction of the refinery many not require the use of strike termination points or down conductors.

 

[oldsparky52]

When I wired fuel systems we were required to install (2) ground rods at opposite sides of the tanks and bond the tank to the ground rod. The theory as I remember it was the lighting was not going to damage the tank but they wanted the lightning to drain. It was not an NEC requirement at the time, but some NFPA document (that I don't remember).

 

[fbhwt]

When I wired fuel systems we were required to install (2) ground rods at opposite sides of the tanks and bond the tank to the ground rod. The theory as I remember it was the lighting was not going to damage the tank but they wanted the lightning to drain. It was not an NEC requirement at the time, but some NFPA document (that I don't remember).

NFPA 780 Chapter 7 Protection for Structures Containing Flammable Vapors, Flammable Gases, or Liquids That Can Give Off Flammable Vapors
7.2.2 Inherent Protection. Metallic structures that are electrically continuous; tightly sealed to prevent the escape of liquids, vapors, or gases; and of 3/16in. (4.8mm) thickness or greater to withstand direct strikes shall be considered to be inherently self-protecting.

7.3.7 Grounding.
7.3.7.1 A ground ring electrode or ground loop conductor supplemented by grounding electrodes as identified in 4.13.2 through 4.13.7 shall be provided for structures containing flammable vapors, flammable gases, or liquids that can give off flammable vapors.
7.3.7.2 A metal tank shall be grounded by one of the following methods:
(1) A tank shall be connected without insulated joints to a grounded metallic piping system.
(2) A vertical cylindrical tank shall rest on earth or concrete and shall be at least 20ft. (6m) in diameter, or shall rest on bituminous pavement and shall be at least 50ft. (15m) in diameter.
(3) A tank shall be grounded through a minimum of two grounding electrodes, as described in section 4.13, at maximum 100ft. (30m) intervals along the perimeter of the tank.
(4) A tank installation using an insulating membrane beneath for environmental or other reasons shall be grounded as in 7.3.7.2(3).