The duration of tests to determine the efficiency of a hand-fired
boiler, should be 10 hours of continuous running, or such time as may be
required to burn a total of 250 pounds of coal per square foot of grate.
In the case of a boiler using a mechanical stoker, the duration, where
practicable, should be at least 24 hours. If the stoker is of a type
that permits the quantity and condition of the fuel bed at beginning and
end of the test to be accurately estimated, the duration may be reduced
to 10 hours, or such time as may be required to burn the above noted
total of 250 pounds per square foot.
In commercial tests where the service requires continuous
operation night and day, with frequent shifts of firemen, the
duration of the test, whether the boilers are hand fired or
stoker fired, should be at least 24 hours. Likewise in
commercial tests, either of a single boiler or of a plant of
several boilers, which operate regularly a certain number of
hours and during the balance of the day the fires are banked,
the duration should not be less than 24 hours.
The duration of tests to determine the maximum evaporative
capacity of a boiler, without determining the efficiency, should
not be less than 3 hours.