I.A.T.S.E 477 Clarification of Lightning Policy

1) National Lightning Safety Institute (NLSI) recommends the suspension of outdoor activities if lightning is within a six mile range, and recommends remaining in shelter thirty minutes after lightning activity has passed.  Lightning range can be detected via commercially available detectors, or calculated by the five second rule, i.e.; sound travels one mile in five seconds.  If the difference between lightning strike and thunder associated with is 15 seconds, the strike is approximately 3 miles away.  NLSI states that if you can see lightning and hear the thunder associated with the activity, lightning is within a six to eight mile range.  Indeed, lightning strike can range six to eight miles.   

2) IATSE 477’s policy towards lightning activity:

a) If lightning is seen and thunder heard, all human occupied lifts shall be lowered to the ground and unmanned.  Unmanned lifts must be secured and all personnel will be required to remain at a safe distance. 

b) If lightning is seen and thunder heard, production shall direct all but essential staff to shelter. 

c) If lightning activity is within a six mile range, all outdoor production activity shall cease, and employees shall be sheltered until thirty minutes after the last lightning activity.