Next in importance after the skill necessary for the steam generator
and the engine, is the proper arrangement and care and management of
the pipes and valves belonging to a steam plant.
It is the first thing an engineer does in taking charge of a new place,
to ascertain the exact course and operation of the water, steam, drain
and other pipes.
Examiners for licensing marine and land engineers base their questions
much more to ascertain the applicant’s knowledge of piping than is
generally known; hence the importance of the “points” in the succeeding
pages relating to this subject.
Pipes are used for very many purposes in connection with the boiler
room, and of course vary in size, in material and in strength,
according to the purposes for which they are designed. There are pipes
for conveying and delivering illuminating gas; pipes for conveying and
delivering drinking water, and for fire purposes; pipes for draining
and carrying off sewage and surface water; pipes for delivering hot
water under high pressure, for heating purposes and power; pipes
for delivering live steam under pressure, for heating purposes and
power; pipes for delivering compressed air, for purposes of power and
ventilation; pipes for conveying mineral oils, etc.
In Figs. 111, 112 113 and 114 are given approximate sizes of gas
pipe and boiler tubes, taken from the catalogue of one of the oldest
steamfitting establishments in the country. It will be observed that
the size of gas pipe is computed from the internal diameter, while
boiler tubes are estimated from the outside: thus, 3 in. gas pipe has
an external diameter of 3-1/2 inches, while 3 in. boiler tubes have an
outside diameter of 3 inches only. It may be noted that boiler-tubes
are made much more accurately as to size than gas pipe; this is
especially true of the outside surfaces which are much smoother in one
case than in the other.