Use of air on the pushover ram to clean standpipes is an acceptable practice…

Filnamn: Use of air on the pushover ram to clean standpipes is an acceptable practice; Standpipes should be cleaned if 20% of the cross sectional area is clocked.

OSHA interpretation letter responding to Bethlehem Steel's variance request on mechanized standpipe cleaners, denying the variance and stating that standpipes should be cleaned when 20% or more of the cross-sectional area is blocked, with inspection before each charge.