1. Technical Paper:
Hydraulic Hose Assembly Care
The benefits of using hydraulically driven systems to power oil spill response equipment The Industry Technical
include; flexible load control, high energy efficiency, intrinsic safety and the ability to power Advisory Committee (ITAC)
equipment remotely from the power source. However, there is a certain amount of basic
maintenance associated with hydraulic systems, without which they can become unreliable
is a forum for information
and even dangerous. Even in wellmaintained systems, hydraulic oil remains a potential exchange between experts
pollutant and spills must be prevented. within the global oil spill
response community. A key
Hydraulic power systems consist of three basic elements: mission of ITAC is the
· A hydraulic pump attached to a prime mover, which can be electrically, diesel or air
driven. development of Technical
· A hydraulic motor operating the equipment. Papers to provide:
· A control circuit.
Hoses, fittings and hose assemblies connect the motor to the pump and transmit high • Advice
pressure hydraulic fluids. These high pressure fluids transfer energy and do useful work.
• Technical Support
Hydraulic systems are used extensively in industry and the cost of repairing or replacing
poorly maintained systems can be high. In addition, fluids under pressure can be very • Benchmarking
dangerous and it is essential that the risk of them escaping from a system is minimised.
The proper care and maintenance of hydraulic hose assemblies is therefore fundamental • Best Practice
to the safe and effective use of hydraulic power systems.
This ITAC paper is intended to give the reader an overview of the basic steps that should
be taken to maximise the working life of a hydraulic hose assembly system. If correctly
implemented these steps should also improve operator safety.
Hose and Fitting care
It is important to recognise when using any assembly that improper selection or improper
use of hoses, tubing, fittings, and assemblies can cause failures, personal injury or
property damage. Understanding the hose assembly and following the installation
instructions provided by manufacturers will reduce these risks.
Some of the main areas for consideration are:
Component Inspection: Prior to assembly, a careful examination of the hose and fittings
must be performed. All components must be checked to ensure that they are the correct
type, size, and length. The hose must be examined for cleanliness, obstructions, blisters,
kinks, cracks, cuts or any visible defects. The fitting and sealing surfaces need to be
inspected for burns, nicks, corrosion or other imperfections. Do not use any substandard or
defective components in an assembly.
Hose and Fitting Assembly: The manufacturer provides guidance on the selection of
hose fittings, hose types and installation. These must be selected to be compatible with the
pressure rating of the system and the environment within which the system is to be used.
Contact:
Minimum Bend Radius: Each manufacturer sets a minimum bend radius according to the Web: www.industrytac.org
hose’s construction and proposed use. Installation of a hose at less then the minimum Email: info@industrytac.org
recommended bend radius may significantly reduce the hose life. Particular attention must Tel: +44 (0)23 8033 1551
be given to prevent sharp bends at the hose connection to the fitting. Any bending during
installation to less than the minimum bend radius should also be avoided. Fax: +44 (0)23 8033 1972
OSRL, Lower William Street,
Southampton, SO14 5QE, UK
The views and advice contained in this paper represent contributions from various ITAC members. Neither ITAC nor any of its members will accept liability for
any loss or damage to property, or personal injury to or death of any person caused or contributed to by the use or misuse of the information contained herein.
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2. Hydraulic Hose Assembly Care
Hose and Machine Tolerances: It is also important when
fitting hoses to design the layout to allow for changes in length
due to machine motion and tolerances.
HoseMaterial Compatibility: It is important to understand
that there are many variables that can affect compatibility of
system fluids with hose materials, these include:
Motion Absorption: It is very important to provide adequate
· Type of fluid hose length to distribute movement and prevent bends smaller
· Fluid pressure than the minimum bend radius.
· Temperature
· Concentration
· Duration of exposure
Environmental conditions can also cause hose and fitting
degradation. Conditions to evaluate when using these
systems in a response include exposure to:
· Ultraviolet light
· Salt water
· Air pollutants
· Extreme temperatures
Lengths: Unnecessarily long hoses can increase pressure
· Ozone drops and affect system performance. When pressurised, a
· Chemicals hose that is too short may pull loose from its fittings, or stress
· Electricity the fitting connections causing premature failures.
· Abrasion damage
System Check: In hydraulic or other liquid systems, eliminate
It is important to consult the manufacturers for more all air entrapment after completing the installation. Follow
information on hose compatibility. manufacturers’ instructions to test the system for possible
malfunctions or leaks. To avoid injury during system checks:
Proper Connection of Ports: Proper physical installation of
the hose assembly requires a correctly installed port · Do not touch any part of the system when checking
connection ensuring that no twist or torque is transferred to the for leaks
hose when the fittings are being tightened. · Stay out of potentially hazardous areas while testing
hose systems
Elbows and Adapters: When fitting hose assembly systems · Relieve system pressure before adjusting
in some cases it is advisable to use elbows or adapters to connections.
relieve hose strain
Hose and Fitting Maintenance and
Replacement guidelines
Even with proper selection and installation, hose life may be
significantly reduced if a continuous maintenance program is
not in place. The frequency of inspection and replacement of
assembly components should be determined by the system’s
Routing: The hose assembly should be routed in such a operating environment, the potential risk from a hose failure
manner so that if a failure does occur, the escaping media will and any past experience of hose failures in the application or
not cause personal injury of property damage. in similar applications.
The views and advice contained in this paper represent contributions from various ITAC members. Neither ITAC nor any of its members will accept liability for
any loss or damage to property, or personal injury to or death of any person caused or contributed to by the use or misuse of the information contained herein.
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3. Hydraulic Hose Assembly Care
Visual Inspection: Any of the following conditions require Hydraulic System Storage and
immediate shut down and replacement of the hose assembly:
Protection
· Fitting slippage on hose.
· Damaged, cracked or charred hose. Hose Sleeves: Sleeves are designed to protect hoses from
· Cracked, damage or badly corroded fittings. abrasive wear and other hostile conditions. They simply slip
· Leaks at fitting or in hose. over the end of a hose assembly, or they may be spilt to
· Kinked, crushed, flattened or twisted hoses. allow them to be installed around a hose assembly already
· Blistered, soft, degraded or loose covers. on equipment. Hose covers are generally made of high
strength fabric, and coated with appropriate materials to
The following items must be tightened, repaired, corrected or resist chemicals, heat, particles, moisture etc.
replaced as required:
Hose storage: Temperature, humidity, ozone, sunlight, oils,
· Leaking fittings. solvents, corrosive liquids, insects, rodents, and radioactive
· Worn clamps, guards or shields. materials can adversely affect hose products. Hoses should
· System fluid level, fluid type and any air entrapment. be stored in a dark, dry atmosphere away from heat sources,
electrical equipment, and the above adverse elements. The
Function Test: Operate the system at maximum operating ideal storage temperature for rubber hose is +50°F (10°C) to
pressure and check for possible malfunctions and leaks. +70°F (21°C), with a maximum of 100°F (38°C).
Personnel must avoid potentially hazardous areas while
testing the system. Whilst a hydraulic assembly system may not be in use on a
daily basis in the spill response industry, a number of
Replacement Intervals: Hose assemblies and seals used on procedures should be enforced while the hoses are stored.
Hose Fittings and adapters will eventually age, harden, wear Routine hydraulic operational checks should be made on all
and deteriorate under thermal cycling and compression set. hydraulic hoses based on a 6 monthly and 12 monthly
Hose assemblies and all seals should be inspected and maintenance schedule. Maintenance checks involve a full
replaced at specific replacement intervals based on previous system check, run up to normal operating pressure,
service life, industry recommendations, or when failures could inspection of hoses for damage, cuts, ferrule slip back,
result in unacceptable downtime, damage or injury risk. coupling integrity and leakage. The date of manufacture of
the hoses also needs to be checked.
Hose inspection and failure: From time to time hose
assemblies will fail if they are not replaced at appropriate time Any power pack used with spill equipment will have internal
intervals. Usually these failures are the result of some form hydraulic hose systems which will also have to be checked
of misapplication, abuse, wear or failure to perform proper and maintained. As above; these internal hoses are checked
maintenance. and the system loaded to full pressure for up to one hour
when carrying out maintenance checks.
When hoses fail, the high pressure fluids can escape in a
stream which may or may not be visible to the user. Under Hose Storage Life: Manufacturers and safety standards
no circumstances should the user attempt to locate the leak generally stipulate a storage life for hydraulic hoses and
by feeling with their hands or any part of the body. High these standards vary around the world. The difficulty for
pressure fluids can penetrate the skin and cause severe response organisations is that the standards are generally
tissue damage. built around hose assemblies in continuous service, or
certainly with much greater service life than those
If hose failure occurs shut down the equipment immediately experienced in oil spill response activities. The counter to
and leave until pressure has been completely released from this lack of operational use, which causes the hose to only be
the hose assembly. Simply shutting down the hydraulic exposed to hydraulic pressure for limited periods, is the more
pump may not eliminate the pressure in the hose assembly. arduous operating environment in which they are used.
It may take some time for the pressure to reduce to a safe Hoses can be dragged across decks and jetties, trailed into
level for inspection. The hose assembly and equipment then seawater and more generally abused than normal plant
can be checked and faulty components replaced. hoses. For this reason a system of rigorous inspection, and
periodic testing should be included in the maintenance
Seals used in fittings and adapters: All seals, such as programme rather than simply using a pure replacement
Dowty and Elastomeric, will eventually age, harden, wear and programme. Nonetheless, hoses do need periodic
deteriorate under thermal cycling and compression set. replacement and it is important to track the age of the
These seals should be inspected regularly and replaced assembly and monitor its condition.
when needed.
The views and advice contained in this paper represent contributions from various ITAC members. Neither ITAC nor any of its members will accept liability for
any loss or damage to property, or personal injury to or death of any person caused or contributed to by the use or misuse of the information contained herein.
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4. Hydraulic Hose Assembly Care
The date of manufacture of hoses is generally marked on the When hydraulic systems are operating, hydraulic fluid
hose and other information is provided, for example: temperatures range from 165° to 185°F due to the high
pressure and represent a potential burn hazard. Hydraulic
· R1 ~ 2Q/05 marked on a hose shows it is a single oil is a fire hazard and when ignited can cause severe burns
nd
wire construction hose made in the 2 quarter of or fatalities.
2005
Remember never search for a pinhole leak by running your
· R2 ~ 4Q/05 would denote a two wire construction hand or finger along a hydraulic hose. Hot hydraulic oil at
hose made in the fourth quarter of 2005. high pressure can puncture gloves and penetrate several
inches into soft tissue.
There are many different types of hoses and assemblies in
production around the world and governments and
manufacturers have different standards regarding safety and
hose care. Oil Spill Response Organizations (OSROs) Tips on Hose Assembly Care and
generally work over and above the stipulated standards,
however government guidelines, such as the British Maintenance
standards, should be used as a benchmark.
Recognized industry standards ensure that the user will Ø Try to fit male fittings on hoses and
adhere to a maintenance schedule and understand the safety females on machines. Male fittings are
implication if not met, however it is the users duty of care to easier to clean if they are dragged through
ensure these checks are not only carried out in maintenance
but during any operation as well and at regular intervals. It is sand etc.
the responsibility of the organisation to clearly identify what is
involved in all the ‘inuse’ and ‘maintenance’ checks. Ø Always clean fittings before connection.
Ø Always ensure caps and plugs are fitted
Inuse Safety Considerations on hoses when not in use.
PreUse Activities: It is important for every user to Ø Store hoses out of sunlight. Hoses left in
thoroughly review and understand information provided in the direct sunlight will degrade and high
equipment operator’s manual with particular attention being pressures will be generated when oil
given to descriptions of safety procedures. Risk Assessments expands in hose making connection
should be carried out before using the equipment.
difficult.
Prior to use, always inspect hydraulic hoses and fittings for
defects or leaks and to ensure that they are securely Ø Use a pressure relief tool to release
attached at connection points. Confirm that lowpressure pressurelocked hoses. Do not bang
hoses or fittings are not connected to highpressure hydraulic
systems or pumps. If a hydraulic system fails the preuse
hoses on deck, floor etc to release locked
inspection, notify your supervisor and follow all procedures to pressure.
ensure it is marked ‘out of service’ until repaired.
Ø Always wear safety goggles when
handling or working with pressurised
Operating Precautions: Before starting the engine, look to
see that people and obstructions are clear of the equipment. hoses.
Never support any implement or equipment by its hydraulics.
Ø Do not use hydraulic hoses as lifting or
Always shut the engine off and release all hydraulic pressure mooring lines.
before disconnecting, performing maintenance or making
repairs. Beware of any hydraulic pressure that may be stored
in pressure vessels or accumulators. Always use supports, Ø Use protective tape (Densil) to protect
jacks, stands, or blocks to prevent movement of hydraulic fittings from corrosion.
implements or components.
The views and advice contained in this paper represent contributions from various ITAC members. Neither ITAC nor any of its members will accept liability for
any loss or damage to property, or personal injury to or death of any person caused or contributed to by the use or misuse of the information contained herein.
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