255.721 Distribution systems: patrolling.

(a)The frequency of patrolling mains must be determined by the severity of the conditions which could cause failure or leakage, and the consequent hazards to public safety.#

(b)Mains in places or on structures where anticipated physical movement or external loading could cause failure or leakage must be patrolled at intervals not exceeding 4½ months, but at least four times each calendar year.#

(c)Distribution lines operating at 125 psig (862 kPa) or more in Class 3 and 4 locations must comply with the transmission patrolling requirements in section 255.705 of this Part.#