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Parker Tech Bulletin

This document provides terminology and guidelines for selecting hoses and fittings for fluid transfer systems. It discusses that the working pressure of hoses and fittings must be equal to or greater than the maximum system pressure. It also describes proof pressure tests that pressurize hose assemblies to twice the working pressure without leakage. Additionally, it notes that hoses have a burst pressure design factor of 4 times the published working pressure and that burst pressure should not determine hose selection. Fluid and ambient temperatures must also stay within the hose's recommended range to avoid degradation.

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100 views1 page

Parker Tech Bulletin

This document provides terminology and guidelines for selecting hoses and fittings for fluid transfer systems. It discusses that the working pressure of hoses and fittings must be equal to or greater than the maximum system pressure. It also describes proof pressure tests that pressurize hose assemblies to twice the working pressure without leakage. Additionally, it notes that hoses have a burst pressure design factor of 4 times the published working pressure and that burst pressure should not determine hose selection. Fluid and ambient temperatures must also stay within the hose's recommended range to avoid degradation.

Uploaded by

jc
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Technical Handbook Hose and Fittings Terminology

– The basics

Working Pressure
Hose and fitting selection must be made so that the published maximum
recommended working pressure of the Hose and fitting are equal to, or greater
than the maximum system pressure. Surge pressures or peak transient pressures
in the system must be below the maximum working pressure of the hose assembly.
Surge pressures and peak pressures can usually only be determined by sensitive
electrical instrumentation that measures and indicates pressures at mili-second
intervals. Mechanical pressure gauges indicate only average pressures and cannot
be used to determine surge pressures or peak transient pressures.

Proof Pressure Test


This test is typically carried out on customer request according to a method defined by the ISO 1402
standard. The test should be made at normal ambient temperature with a proof test bench using water
or another suitable liquid. The hose assembly should be pressurised for between 30 to 60 seconds at
twice the working pressure of the hose assembly. There should be no leakage or pressure drop.
A complete test report should be provided together with the hose assembly to the customer.

Burst Pressure
All hoses in this catalogue have a pressure design
factor of 4:1, implying therefore that the burst pressure
(hose destruction) is minimum 4 times the published
working pressure.
Published burst pressure ratings for hose are for
manufacturing test purposes only – burst pressure
should never play a role in the selection of a hose. x x x

Fluid Compatibility
The hose assembly (hose inner tube, hose outer cover and hose fittings) must be chemically
compatible to both the fluid being conveyed by the hose as well as the medium surrounding it.
(the chemical resistance table contained in the catalogue, indicates only the resistance of the
hose innertube to the respective fluid)

Temperature Range Temperature range


In order not to negatively effect the properties of the rubber hoses it
should be made certain that fluid and ambient temperatures, both steady
and transient, do not exceed the limitations of the hose as published in 
the catalogue. Temperatures below and above the recommended limit +100
will degrade the hose and failure may occur and release fluid.
The mechanical properties of the hose are also influenced by low or high

-50

temperatures and should be considered when designing the system.

Aa-2 Bulletin C4400-A/UK

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