Generators are built in such a way that it is impossible for the acetylene
to escape from the gas holding compartment during the recharging process.
This is accomplished (1) by connecting the water inlet pipe opening with a
shut off valve in such a way that the inlet cannot be uncovered or opened
without first closing the shut off valve with the same movement of the
operator; (2) by incorporating an automatic or hydraulic one-way valve so
that this valve closes and acts as a check when the gas attempts to flow
from the holder back to the generating chamber, or by any other means that
will positively accomplish this result.

In generators having no separate gas holding chamber but carrying the
supply in the same compartment in which it is generated, the gas contained
under pressure is allowed to escape through vent pipes into the outside
air before recharging with carbide. As in the former case, the parts are
so interlocked that it is impossible to introduce carbide or water without
first allowing the escape of the gas in the generator.

It is required by the insurance rules that the entire change of carbide
while in the generator be held in such a way that it may be entirely
removed without difficulty in case the necessity should arise.

Generators should be cleaned and recharged at regular stated intervals.
This work should be done during daylight hours only and likewise all
repairs should be made at such a time that artificial light is not needed.
Where it is absolutely necessary to use artificial light it should be
provided only by incandescent electric lamps enclosed in gas tight globes.

In charging generating chambers the old ash and all residue must first be
cleaned out and the operator should be sure that no drain or other pipe has