All hoses have two pressure ratings: a working
pressure rating and a bursting pressure rating.
The working pressure rating represents com-
mon pressures a hose experiences each time the
equipment is operated. Hoses that operate within
their working pressure ratings will move just as
much fluid at the end of the day as they did at
the beginning.
It’s important to remember that working
pressure is not fixed — higher temperatures affect
the materials hoses are made from and can change
ratings. When the air temperature is above 80ºF,
the working pressure rating drops. For instance,
a hose with a working pressure rating of 150 psi
will actually hold less pressure when it’s more than
80
ºF. Thus, it is very important to select hoses
that have working pressure ratings that are higher
than the pump pressure. That way, the hoses will
still perform even when temperatures are high.
The bursting pressure rating is the highest
pressure a hose will maintain before it fails. Hoses
experience such high pressures when a bypass or
relief valve fails. Hoses can take high pressures for
a time before the hose’s reinforcements fail and
the hose bursts.
Bursting pressure ratings are normally four
times higher than working pressure ratings.
But, depending on the manufacturer, these safety
margins may vary. The difference between the
working and bursting pressure ratings is a built-in
safety margin. When operators keep the hose
within the working pressure range, the hose
should not fail as a result of pressure alone.
Always remember that pressure ratings are
assigned to new hoses. Over time, as hoses wear
from both the inside and out, the actual working
and bursting pressure ratings will decrease. Routine
maintenance on any application equipment should
include replacing hoses when necessary.
Manufacturers may or may not stamp pressure
ratings directly on hoses. Some manufacturers
Cuts in hose covers expose the
reinforcement, which can lead
to a premature failure.
Most hoses are labeled with their working pressures.
If not, examine the hose’s shipping container or reel, or consult the supplier.
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