All,

How frequently do you replace oil carrying rubber hoses on screw air compressors, such as Ingersol-Rand and alike ?

Thanks in advance,
Dave

From an RCM perspective, several things to consider.

Is a leak a big problem? If not, wait until it leaks or shows other evidence of aging (cracks) to replace it. There are applications where leak is a big problem - we have one vertical motor with oil lubricated bottom bearing with sightglass connected to reservoir at bottom/top of sightglass. The bottom connection is made by rubber hose. Leak at this hose could in theory drain the bearing oil reservoir.

Then there is the material vs the environmental factors. Higher temperature tends to age most elastomers faster. Some age quickly in outdoor sunlight (uv). Many don't do well in presence of synthetic oil (incompatibilities with normal oil tend to be screened out more than with the various synthetic oils).

For Buna N rubber hose used in the motor bottom bearing sightglass described above, we replace every 20 years or when we see leaks.

I agree with the factors affecting hose life. Cracks are the biggest fear here in particular because they can progress very quickly or be missed during an inspection resulting in total oil loss ( very expensive).

Things get aggrevated because of inherent air compressor oil operating condition with relatively high TAN number. A crack in the hose happened just ONCE before and somebody decided to replace the hoses from then on every 12 months, no matter what. No failure occured since, although unlikely this is the remedy. Naturally, no one wants to take responsibility and extend seemingly short interval.

Another option is to replace with flexible stainless steel braided hoses the next time you replace them and then never have to replace them again.