MTBF data for control valves

Why not ask your valve supplier for such data? Who else but the manufacturer would have such comprehensive information?

Be serious Lynlinch - are you honestly going to believe the salesman when he tells you his valves are "maintenance free"? How would the manufacturer even collect such information?

Most every refinery, chemical plant, gas plant etc will have these figures for their own plant and probably compare themselves with other plants in the same group or with industry wide figures. See if you can get in touch with the reliability engineer of a plant such as mentioned in your area. There are also commercially available reliability figures for most equipment for benchmarking purposes.

Do you mean that you have no expectations of valve performance before you purchase a valve? How gullible can you be?

Of course I have expectations for MTBF. Where in my post did I indicate otherwise?That is why I measure our results and compare them to similar industry averages and specify the valves to the highest of standards.

Gullibility is believing the BS given by the salesman (call him a Sales Engineer if you will).

Ref Oreda 2002 , They have provided comlete list of MTBF , median

But the data collected is for North Sea area , hence the value may change depending upon ur location

anyways for tabulation its a good source

Regards

Jose

I work in a paper mill, and we find different control valves behave differently based on the product in the pipeline, the ambient conditions around the valves and the general state of repair of the surrounding plant., For example, in the pulper area, valves fail more frequently because of wire or other bits in the line; the high humidity and concentration of chlorine in the air, and whether or not the pipeline remains secure in its brackets. The bracketing tends to fail more frequently than in other parts of the mill, causing excess movement on the pipe when the valve operates. This causes eventual physical failure of the valve. It's not always the valve that fails, By far the most common valve related failure we have is the feedback proxy. The identical valve in a different part of the mill only suffers from normal wear and tear, so it fails much less frequently.

You can have the same valve in 2 different parts of a process, and have two distinct sets of MTBF values. Also, depending on whether you replace or repair valves, the MTBF value could also be a product of the quality of the repair done. This would be an interesting metric if you suspected a sub-standard contractor, or a lazy member of staff.

The first stop must be the installation's maintenance records, surely?!