Lighting Protection & NFPA 780

  1. Down stream conductors shall be used where in regards to architectural changes?
    at architectural elevation changes, generators, water towers, and cooling towers.  Main down leads may be used on building steel.
  2. An air terminal is to be what size in diameter and of what type of metal?
    1/2" in diameter and atleast 12" above the protected area, but 24" long.
  3. Air terminals are to be spaced how far apart?
    25 feet maximum spacing with 24" high terminals along the roof edge and no greater than 50ft across roofs or laterally.
  4. Bonding to structural steel for lightning protection for use as a down conductor is allowed every how many feet?
    every 100ft max. at roof level and 60ft or less at grade.
  5. How often are downleads supported?
    every 3ft.
  6. What is the minimum bending radius for one 90 degree bend for a down conductor?
    8" radius minimum
  7. Air terminals will be located a maximum of how far from the roof edge?
    2ft.
  8. Any equipment within what distance of the lightning protection system should be bonded?
    Anything of a metallic nature including gas mains at within 6ft of the lightning protection system.
  9. copper should not be mounted on what galvanic surfaces?
    aluminum surface, bare zinc, or galvanized sheet metal. source: pg 24 of submittal and NEC.
  10. The grounding conductor as defined by NFPA780 should be a minimum of how far into the soil?
    30"
  11. The ground rod for the lightning protection should be 5/8 by 8ft long per the NFPA780 2011 publication, but the submittals may exceed this with what size?
    3/4 dia. and 10ft long.  (since they must be 10ft deep).
Author
johnbowens
ID
339642
Card Set
Lighting Protection & NFPA 780
Description
A summary of the high points regarding the NFPA 780 standard for lighting protection and based on the 2011 NFPA 780 code.
Updated