Burst Pressure and Safety Factor
Burst pressure is the pressure at which a hose ruptures in the laboratory and is never used as a working pressure. The common safety factor on hydraulic hoses is 4:1; that is, a hose allowed a working pressure of 250 bar has a burst pressure of about 1,000 bar. The factor represents the allowance for surge and fatigue.
The system's actual peak pressure can be higher than the relief valve setting. The pressure surge created when a valve closes suddenly rises briefly well above the set value. The safety factor is exactly what covers these hard to measure peak values and fatigue over millions of cycles.
- Selection rule: the hose's continuous working pressure must be higher than the system's relief valve setting pressure.
- Impulse service: in circuits that reverse direction frequently, a hose with a higher factor or with documented impulse resistance is selected.
- Fitting match: the weakest link determines the strength of the chain; putting a 250 bar fitting on a 400 bar hose makes the hose's rating meaningless.
Adding electronic remote control does not change system pressure, but it can increase the machine's cycle count. Since hose life depends on cycle count far more than on pressure, it makes sense to shorten the hose inspection interval on heavily used machines.
Where this term is used: How Are Manual Hydraulic Levers Controlled Remotely? A Comparison of 6 Methods