LIGHTNING PROTECTION SYSTEMS
Lightning protection systems are used in geographical locations that have more than five thunderstorm days per
year. Lightning protection systems should be installed on buildings and other structures used for processing,
handling, or storing explosives, ammunition, and other hazardous materials. Approved lightning systems are the
integrally-mounted systems, the separately-mounted shielding systems (mast type), and the separately-mounted
shielding systems (overhead-wire type).
Integrally-Mounted Systems
The integrally-mounted systems (Figure 4) consist of sharp or blunt-ground air terminals of 2-foot minimum height
configured on the structure. Down conductors are as nearly vertical as possible without bends. Any bend must
be as gradual as possible, having a minimum radius of 8 inches, and not exceeding 90 degrees.
Figure 4. Integrally-mounted lighting protection system.
Separately-Mounted Shielding Systems (Mast Type)
The separately-mounted shielding systems (mast type)(Figure 5) uses masts that are remote from the structure to
provide the primary attachment point of a lightning discharge.
MM0149
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