Hydraulic Hoses

In general, If the hose has completed their total life, its use has been obtained. During the hose's life (not knowing your actual application) it experiences many factors which cause the degradation of the materials (pressures, temps, chemical reactions, time, environmental, mechanical damage etc). Re-using a hose that has already provided ample service life can be dangerous. I'm not saying that it cant be done, but is not advisable. If injury occurs due to the failure of the hose, who will be held accountable? I know i would not want to be the responsible party for any incident involving a hose which i signed-off on. (again, I do not know your application, and maybe you are running low psi and the catastrophic failure of a hose may not matter?)

To answer (or not answer) your question, i do not know of a standard practice for certifying used hose for recirculation into another service life. There may be something out there, but I'm not aware of it.

There are many test specifications to qualify a hose. They range fom MS military specs to SAE J-specs for automotive to SAE AS-specs for aerospace.

It depends on the hose type and application.

I am not aware of a specification to re-certify a hose as you would a pressure vessel. The major factor in the life of a hose is the material. Most hose material degrades over time. Brand new hoses that have never seen service are scrapped due to their age all of the time. Also many hoses have an exterior cover so you can not see the true condition of the functioning hose material.

Generally hoses are seen as a service part. For safety reasons your hose should be replaced.

If you could give me the hose type and application I may be able to give you more specific information. If you want to review a typical hydraulic hose test specification you could start with SAE J343 for 100R series hose and assemblies.

The only safe use of such hoses that I know of has been where the high pressure side hoses have been used as very low pressure return hoses or used in very low pressure situations or on equipment where a possible leak or catastrophic failure is acceptable.

NOW,the saving of and use of old hoses and belts Until a PROPER replacement was available was a common and accepted rule in every place I worked and has personally saved me from being stranded on land,inland waters and open sea away from work.

Just because it is new and has just been tested,does not mean that it is BETTER than the old ones.The pressure testing of hoses used with hazardous materials was part of my job for many years.The hoses were most apt to fail shortly after the testing than at any other time when records were checked!Were we stressing them by checking them by the manufacters specifications just as they were checked before being sold?Alfred

A bit of a grey area the prediction of hose condition, SAE J1273 generally recommends the following checks:

(A) Flex the hose to the minimum bend radius and compare it with a new hose. After flexing, examine the cover and tube for cracks (difficult in an assembly without a bore scope), if any appear , no matter how small reject the hose.

(B) If the hose is wire reinforced, and the hose is unusually stiff, or a cracking sound is heard during flexing, reject the hose.

(C) Look for any indication of rust on the hose cover or adjacent to the hose end fitting, either of these would be cause for rejection.

(D) Any seepage from the end fitting or cover blistering, this should be rejected.

(E) As belt and braces, proof test in accordance with SAE J343 to double the working pressure. This should give a reasonable indication of the hose condition should (A) , (B) , (C) and (D) prove to be satisfactory and more assurance is required.

Hope this helps.

sir your help is appreciated and i m thankful for your valuable advice ! sir can u send me the relevant extracts of SAE J1273? help and time is appreciated ?

-points for maintenance inspection in SAE J1273.

Visually inspect hose and fittings for:

a. Leaks at hose fitting or in hose

b. Damaged, cut, or abraded cover

c. Exposed reinforcement

d. Kinked, crushed, flattened, or twisted hose

e. Hard, stiff, heat cracked, or charred hose

f. Blistered, soft, degraded, or loose cover

g. Cracked, damaged, or badly corroded fittings

h. Fitting slippage on hose

i. Other signs of significant deterioration

For testing of hoses it basically says to go back to the manufacturer.

If their failure could endanger a life don't use them !

I'm not sure where you are located but considering the low cost and the almost excessive availability of hydraulic hose assemblies I don't think it's worth the risk or typical machine down time that would occur in the event of a failure.