Predicting the life of hydraulic hose

A variety of service factors affect how long a hose assembly will last. Factors such as operating conditions, ambient temperature, pressure, and the type of hydraulic fluid all play a role in how long a hose assembly survives in service. Not a week goes by without someone asking, "How long will the hoses last on our system?" Society of Automotive Engineers (SAE) specifications state the shelf life of bulk rubber hose is 10 years from the date of manufacture and is considered unlimited for thermoplastic hose, if stored in subdued light and controlled temperatures with no fittings attached. But in use, so many variables come into play that it is impossible to exactly predict the service life of a hose assembly. However, understanding important operating parameters that affect a hose, combined with a bit of experience, can help guide users as to when an assembly should be replaced. Key factors to consider include size, temperature, application, media, and pressure. refers to the fact that every hose is designed for specific pressures, flows, temperatures, and so on, and deviating from these will shorten its life. This may seem obvious, but users sometimes undersize a hose to increase flow rate and run equipment faster, or simply because of space constraints. But excessive flow velocity will damage the inner tube, especially at bends, and lead to premature failure. It can also raise fluid temperature and have a detrimental effect on pumps, filters, and other system components. Some users take the opposite approach and specify a larger-than-required hose to keep flow velocity low and fluid cool. Such a system increases costs and creates problems such as routing a larger hose in a smaller envelope. Also, the effects of fluids and aging on hose materials are independent of size, so spending more on an oversized assembly