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Reg. 5
Modification of Formulae |
| (i) |
Under the Regulations for determining
the working pressure to be allowed on various parts of boilers,
the material to which the formulae apply shall in the absence
of express provision to the contrary be steel complying with
the requirements of Chapter II. |
| (ii) |
Where no test certificate for plates
and rivets are produced, the material may be treated as iron,
if the Chief Inspector is satisfied that the material is of
suitable boiler quality. If in such cases the Chief Inspector
is clearly satisfied that the material is of good quality, a
higher strength than that allowed for iron may be permitted
but the strength of the plates shall not, save for special reasons,
be assumed to be more than 26 tons per square inch. In such
cases the values of tensile and shear strength shall not be
more than 26 and 21 tons per square inch for steel, and 21 and
18 tons per square inch for iron. For iron across the grain
the tensile strength may be 18 tons per square inch. |
| (iii) |
For flat plates of copper, the working pressure as found
from the formulae, reduced by 50 per cent shall be the working
pressure permitted.
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