Page 28 - GoodYear Rubber Products 1-866-711-4673 HBD Thermoid Inc

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GENERAL INFORMATION
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Product information is subject to change. For full details, visit our website or contact Customer Service.
AL
FACTORS AFFECTING HOSE
SERVICE LIFE
All hose has a limited life for a given application . This is true
even if the proper hose has been selected for the application; it is
used within rated pressures, temperatures and environmental con-
ditions; and it is properly inspected and maintained. This is because
the elastomers and reinforcement used to construct the hose will
break down over time and with use. In addition, there are a number
of factors that can adversely affect the service life of a hose. The
major ones are:
1. External Abuse – Kinking, bending, high end pull, crushing,
abrasion, exceeding the recommended minimum bend radius,
exposure to chemicals and other abuse or damage will reduce
the service life and performance of you hose. This may be the
case even though the hose may appear to be undamaged from
exterior appearance. Hoses should not be stretched, run over
by equipment, or used to hoist, carry or pull objects. Hoses
should not be bent beyond recommended minimum bend
radius. This could result in kinks which could increase pressure
and hose damage that could reduce pressure resistance.
Large diameter hoses may require additional support to reduce
stretching, kinking and external abuse.
2. System Pressures – Never use hose at pressures that
exceed its ratings. A system (or device or application) can
have varied pressures caused by source, operator action or
mechanical components. It is the responsibility of the purchaser
or user to accurately determine the maximum system pressure.
Steady state pressure can be measured readily by gauges.
Surge pressures are difficult to measure and may require the
use of electronic pressure sensing devices. “Hammer effects”
refers to sudden blockage or stoppage of the system that
causes pressure spikes. This can damage or even cause
catastrophic failure of the hose or system.
3. High Temperatures – Never use hose at temperatures that
exceed its ratings. High temperatures can degrade a hose
very quickly, resulting in shortened service life. The allowable
temperature ranges for the Thermoid hoses are shown on the
following pages. These are for internal product temperatures
and assume external or ambient temperatures do not exceed
the recommended working temperature of the fluid. Where
external temperatures are higher than these ranges, contact
your HBD/Thermoid Customer Service Representative for
recommendations. Fluid and environmental temperatures
that are high, but within working temperature of hose, still
shorten hose life.
4. Low Temperatures – Never use hose at lower temperatures
than recommended. Doing so could cause the hose to crack
or break.
5. Misapplication – HBD/Thermoid designs and supplies a
variety of hoses. Always select the right hose for the
application. HBD/Thermoid disclaims liability for misapplication
of its product. Contact your HBD/Thermoid Customer Service
Representative for application assistance.
6. Internal Abrasion – Applications involving abrasive fluids,
particularly where the hose makes one or more bends, will
reduce the service life of the hose.
7. Flexing and Vibration – Flexing, twisting, vibration or other
movement of the hose may shorten service life.
8. Modifications to the Hose – Repairing the hose, improperly
coupling or re-coupling of the hose, or use of inappropriate
fittings and other modifications to the hose will shorten service
life and possibly cause immediate failure.
9. Improper Installation – Installing hose assemblies in a manner
where the hose is subjected to a torqued condition (twisted
layline), will reduce the life of the hose significantly.
STEAM HOSE WARNING
Steam heat is hotter than boiling water (212°F, 100°C) and
increases in temperature as pressure increases. The danger from
steam in industrial applications is due to the great heat and
pressures involved. Water changes to steam at higher temperatures
when under pressure. If the steam escapes, massive quantities of
heat are released. This, combined with high pressures, can prove
to be dangerous for the operator. Use only steam hoses
designed for these applications. A steam hose should never
be used to carry pressures or temperatures higher than it is
rated to handle, in spite of any safety factor.
Super-
heated
Steam
Hot
Water
Temperature,
°F
450
400
350
300
250
200
0 50 100 150 200 250
Gauge Pressure, psi
X
STEAM CHART
The dotted line shows the process of saturated steam being
transformed into superheated steam. If a steam line is at a
pressure of 150 psi, and a temperature of 366°F, it contains
saturated steam. If the pressure is substantially reduced by the
expansion of the steam (such as the sudden opening of a valve
or the steam passing into a larger pipe or hose), the condition
of the steam follows the dotted line to some point X in the
superheated steam area. This condition may not last very
long, but the superheated steam tends to deteriorate the tube
stock in ordinary steam hose intended for use with saturated
steam. This usually results in hose failure.