Valve Size and Pipe Class

You speaking of industrial Hydraulics?

3000# is a kind of industry standard pressure rating for most standard hydraulic components.

Always over-design, and expect the worst case scenario.

Thanks for your prompt answer. Can we use small valves at just design, not over-design?

Not sure I understand what you are asking.

Are you trying to find a only 600psi valve? You might find one, but i know you can find a 3000psi, which will work the same, only with a much higher saftey factor.

Please Clarify your question.

Yah. I'm trying to know if I can accept this valve (#600). I agree with you #3000 should be better, but the supplier only have valves #600.

If the Valve is rated at 600psi, and your system runs at (or less than) 600psi, you'll be fine. Just dont ever run a valve beyond its rating.

What is the standard that the valve was designed/manufactured?

ASME B16.34, perhaps?

(you also need to provide material of construction and temperature)

The line size decreases and pressure increases .so as to sustain the pressure the valve class is always higher .

Hi,

I very well understand your question, as during my initial days, I too had this doubt. I had discussion with industry people and the reason is:

Valve manufacturers have standardized the valves. If they maintain 1/2" valves from 150# to 600#, it will increase their product range. Moreover, if you look at the otherside of the coin, it is useful to the end users also. It helps to maintain less inventory.

So, it is standradization which is reason and this is beneficial to both producers and end-users.

Dear Kumaran,

Yes, you were clear, and make sense.

Thanks for your support

we are takling from Technical (process point of view ) pressure increses as size decreses so as to sustain higher class valve is used

It is normal where I work at to use an 800 lb class valve on small steam and condensate lines (under 2.5 inch OD) even though the pipe is at less pressure rating say 50 or 150 lb. steam. The small valves are cheap and provide allot of safety factor. On these same lines we would use a 3000lb rated socket weld fitting instead of a 1500 lb. or less socket weld fitting for the same reasons even though either would work. I am not aware of a socket weld small bore valve with a lower rating although they may exist. By using an over rated valve we can also standardize on some materials and prevent someone from installing a lower class valve into a into a higher rated line. On pipe sizes over 2.5 inch OD the cost of over rating on these valves is allot more although we do usually go to the next class rating for valves in most cases.(150 class valve on a 50lb steam line and a 300 lb. class valve on a 150 lb. line and so on.)