Reg. 330, Reg. 331, Reg. 332, Reg.
Test Connections-Inspectors Pressure Gauge
|Every boiler shall be fitted
with a valve or cock carrying in a vertical position a
receiving screw for attachment of the Inspectors
pressure gauge. The receiving socket shall be tapped for
M20 x 1.5 metric threads and shall be fitted with an easily
||Fusible plugs shall
be of sufficient height and fitted in such a position
as to give early protection to all parts of the boiler
liable to damage by the direct application of furnace
heat in the event of shortness of water.
||On boilers having
wet back reversing chamber, a minimum of two fusible plugs
shall be fitted; one on the crown of the reversing chamber
and the other on one of the tube plates. On boilers not
having Wet back reversing chamber, at least one fusible
plug shall be provided on the front end tube plate. The
plug shall be fitted in such a way that in the event of
fusion of the plug, the pressure inside the boiler shall
push the pellets out.
Note: - For example : In Lancashire Boilers the
fusible plugs should be in the crowns of the furnaces
from 12 inches to 18 inches in front of the brickwork
|Fusible plugs shall consist
of an outer body with a central conical passage the smallest
part to be not greater than 1/2 inch for plugs suitable
for pressure up to 100 lbs. per sq. in. and not greater
than 3/8 inch for plugs for pressures exceeding 100 lbs.
per sq. in. The passage shall be closed by a plug secured
by an annual lining of fusible alloy so that the plug
may drop clear if the lining melts.
The portion of the body carrying the fusible metal should
preferably be detachable from the base to allow of easy
replacement without removing the whole fitting from the
|The non-fusible portions of
the plug shall be of bronze except where the nature of
the boiler water precludes the use of a non-ferrous material.
The fusible metal shall be an alloy melting readily at
a temperature not less than 150º F in excess of the
saturated steam temperature at the maximum permissible
working pressure of the boiler.