What is the difference between working burst and proof test pressure

For a piping component,it will have a working pressure,proof test pressure and burst pressure.What is the difference between these pressure specifications for pipe fittings products?

Forged steel flange hydro pressure test

The working pressure means the pressure of the pipe fittings or flanges in the working conditions range,normally called pressure range.

Hot induction bend ready for burst proof test in Hebei Haihao

The proof pressure for the pipe fittings or flanges,which means over-range pressure,is the maximum pressure that may be applied to the pipe fittings or flanges without changing its quality.After the pressure is released,the pipe fittings will recover to the original if the pressure is under the proof pressure limit.

A860 wphy fittings for-CNPC oil pipeline burst testing

The burst pressure is the maximum pressure that can be applied to the pipeline components without physical damage.Burst pressure can be defined as the maximum pressure this pipe fitting can withstand before breaking.When the pressure exceeds the burst pressure,the pipe will explode.

Stainless steel pipe fittings after burst proof testing

For example,the pressure range of the following piping components

Working pressure: less than 5.0 Mpa,

Proof pressure: 3times of working pressure 15.0Mpa,

Burst pressure: 6times of working pressure 30.0Mpa.