LIGHTINING PROTECTION FOR HAZARDOUS AREA

[Engels]

In Brazil, the National Standard (NBR-5419) regarding protection against lightning, establishes that hazardous areas should have yours items placed outside volume to be protected, in other words, the air terminals and down conductors, could not cross the areas that the classification shows as shaded areas in the graphs.

The problem is that, in case of towers or high structures, is not possible to attend this statement. I ask: How do the American and European standards deal with this matter?

Thanks

 

[DonMcC]

In the US, see NFPA 780: Standard for the Installation of Lightning Protection Systems 2000 Edition. If I remember, it costs about 40 US. Chapter 6 is titled: Protection for Structuures Containing Flammable Vapors, Flammable Gases, or Liquids That Can Give Off Flammable Vapors.

 

[Shavner]

As Stated NFPA 780 - Ch 6. gives excellent coverage on the subject. The use of lightning masts is an excellent way to address these problems. The question I have is the Height of the structure in question. For rough estimating a 5200ft2 (480M2) building with a max height (salient Plane) of 45' (13M) we used 6 75 foot steel masts with three #2/0 (70mm2) "catenary" cables strung overhead between the the masts. Basically you want a zone of protection of 100' (30M) around the building with a primary and secondary ground girdles. The easiest way to visualize the 100' zone of protection is to imagine a 100' diameter sphere rolling around the building. with the masts in place as long as the sphere does not touch the building, or come within the sideflash distance you are protected. now there are some more detailed items to it but it gives a general idea to protecting dangerous buildings.

 

[Shavner]

Sorry was typing too fast - 100' RADIUS sphere - And cost can play an important role in the system chosen either a free standing system or a catenary