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HG3555A/42306 Portable Power Unit
Appendix A
SELECTION, INSTALLATION AND MAINTENANCE OF
HOSE AND HOSE ASSEMBLIES
- SAE J1273 MAY 1986*
SAE RECOMMENDED PRACTICE
The following recommendations on selection, installation
and maintenance of hose and hose assemblies was
established by the S.A.E. in 1979 and reaffirmed May
1986. Please read these general instructions carefully.
1. SCOPE
Hose (also includes hose assemblies) has a finite life and
there are a number of factors which will reduce its life.
This recommended practice is intended as a guide to
assist system designers and/or users in the selection,
installation, and maintenance of hose. The designers and
users must make a systematic review of each application
and then select, install, and maintain the hose to fulfill
the requirements of the application. The following are
general guidelines and are not necessarily a complete
list.
Improper selection, installation or maintenance
may result in premature failures, bodily injury, or
property damage.
2. SELECTION
The following is a list of factors which must be
considered before final hose selection can be made.
2.1 Pressure – After determining the system pressure,
hose selection must be made so that the recommended
maximum operating pressure is equal to or greater than
the system pressure. Surge pressures higher than the
maximum operating pressure will shorten hose life and
must be taken into account by the hydraulic designer.
2.2 Suction – Hoses used for suction applications must
be selected to insure the hose will withstand the negative
pressure of the system.
2.3 Temperature – Care must be taken to insure that
fluid and ambient temperatures, both static and
transient, do not exceed the limitations of the hose.
Special care must be taken when routing near hot
manifolds.
2.4 Fluid Compatibility – Hose selection must assure
compatibility of the hose tube, cover, and fittings with
fluid used. Additional caution must be observed in hose
selection for gaseous applications.
Greenlee Textron / Subsidiary of Textron Inc.
2.5 Size – Transmission of power by means of
pressurized fluid varies with pressure and rate of flow.
The size of the components must be adequate to keep
pressure losses to a minimum and avoid damage to the
hose due to heat generation or excessive turbulence.
2.6 Routing – Attention must be given to optimum
routing to minimize inherent problems.
2.7 Environment – Care must be taken to insure that the
hose and fittings are either compatible with or protected
from the environment to which they are exposed.
Environmental conditions such as ultraviolet light, ozone,
salt water, chemicals, and air pollutants can cause
degradation and premature failure and, therefore, must
be considered.
2.8 Mechanical Loads – External forces can significantly
reduce hose life. Mechanical loads which must be
considered include excessive flexing, twist, kinking,
tensile or side loads, bend radius, and vibration. Use of
swivel type fittings or adapters may be required to insure
no twist is put in the hose. Unusual applications may
require special testing prior to hose selection.
2.9 Abrasion – While a hose is designed with a
reasonable level of abrasion resistance, care must be
taken to protect the hose from excessive abrasion which
can result in erosion, snagging and cutting of the hose
cover. Exposure of the reinforcement will significantly
accelerate hose failure.
2.10 Proper End Fitting – Care must be taken to insure
proper compatibility exists between the hose and
coupling selected based on the manufacturer's
recommendations substantiated by testing to industry
standards such as SAE J517d (November, 1976).
2.11 Length – When establishing proper hose length,
motion absorption, hose length changes due to pressure,
as well as hose and machine tolerances must be
considered.
2.12 Specifications and Standards – When selecting
hose, government, industry, and manufacturer's
specifications and recommendations must be reviewed
and applicable.
2.13 Hose Cleanliness – Hose components vary in
cleanliness levels. Care must be taken to insure that the
assemblies selected have an adequate level of
cleanliness for the application.
2.14 Electrical Conductivity – Certain applications
require that the hose be non-conductive to prevent
electrical current flow. Other applications require the
hose to be sufficiently conductive to drain off static
electricity. Hose and fittings must be chosen with these
needs in mind.
21
4455 Boeing Dr., Rockford, IL 61109-2988 815/397-7070
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