Dual Plate Check Valve Standard. API 6D vs API 594

[Macdev]

Hi All,

I got the situation here.

Customer request for the wafer type dual plate check valve with API 6D standard. But we already supplied the wafer type dual plate check valve with API 594.

From my supplier/manufacturer feedback is (The valve (Wafer type) comply to API594. The API 6D is not applicable for this valve.)

My question is

1. If the wafer type dual plate check valve comply to API 594 code, did we need to comply API 6D also or it can be waived.
2. What is the different API 594 and API 6D

Appreciate all answer and advise.

Regards
Macdev

 

[gerhardl]

First: I am not familiar with API 6D, but out of curiosity I took a fast peek at the document.

Why is API 6D, a very widecatching document, with details on a large number of valve constructions, materials and tests, with cross references to a vast number of other regulatives, not applicable for your valve?

The only exception I could see was valves for petroleum subsea, mentioned covered by other specifications.

It is not uncommen that a customer requier several specification regulations covered. Quite another question is how your customers wish to have you prove the construction, and to which particular details of API 6D.
Is any exact wording or details given on this?

 

[JSOSA555]

Those valves are also designed to work in vertical position (the spring needs to be that way) It’s a rule!!!, Because the set point of the PRV must be depending only on the force of the spring, if you install it horizontally, also side forces, sliding and friction affects the setpoint (and you can not messure them) . Also the inlet piping must be the shortest possible. In API and ASME standards you can find some guidelines regarding installation, if you install the valve on the side of the pipe, you must use elbows and additional fittings in order to keep the valve in vertical position, so in this scenario de pressure drop at the inlet of the valve will be higher and you can have problems like chattering.

There are valves desgined to work on gas, vapour, liquid or even 2 phases, depends on the system

Hope this could be helpful

 

[Macdev]

Hi gerhardl

No exact words given by customer, but they provide the datasheet stated API 6D.

The issue right now, customer asking me what is the different between API 594 & API 6D.

Did we need the API 6D if the manufacturer already follow API 594?

 

[Pipingeng100]

API 6D generally talks about the Pipeline valves. It covers only the face to face dimension in the standard.
And the Body wall thickness shall be ASME B16.34.

API 594 specifically designed for Dual Plate Check Valves and it is commonly used in all
kind of engineering industries. It covers the face to face dimensions, Body wall thickness,
Inspection requirements etc.

Better to go for API 594. It clearly depicts the design. API 6D (commonly used for Ball Valves more
than 4") Trunnion mounted. ISO 17292 (upto 4").