(c) Purifiers must contain no carbide for drying purposes.
(d) Purifiers must be located inside of gasholders, or, where necessarily outside, must have no hand-holes which can be opened without first shutting off the gas-supply.
24. PRESSURE REGULATORS.--(a) Must conform to the rules for the construction of other acetylene apparatus so far as they apply and must not be subject to sticking or clogging.
(b) Must be capable of maintaining a uniform pressure, not varying more than four-tenths inch water column, at any load within their rating.
(c) Must be installed between valves in such a manner as to facilitate inspection and repairs.
Class B.--Stationary Apparatus for Central Station Service.
Generators of over 300 lights capacity for central station service are not required to be automatic in operation. Generators of less than 300 lights capacity must be automatic in operation and must comply in every respect with the requirements of Class A.
25. GENERAL RULES. GENERATORS.--(a) Must be substantially constructed of iron or steel and be protected against depreciation by an effective and durable preventive of corrosion.
Galvanising is strongly recommended as a protection against oxidation, and it may to advantage be reinforced by a thorough coating of asphaltum or similar material.
(b) Must contain no copper or alloy of copper in contact with acetylene, excepting in valves.