API vs. B16.34 valve specifications 4

[TMBeau]

I have several quetions:

1. Does the API valve standard cover pressure seal bonnet valves?
2. It appears that API standards do not cover globe valves. Is this true and if yes, why?
3. What is the maximum ASME class allowed by API? I know for B16.34 code valves, the maximum is class 4500
4. Can a valve built to API standards by default satisfy ASME B16.34 requirments?
5. Does the API standard cover all gate valve designs or only certain kinds?

Thanks!

 

[svi]

API and ASME standards are complimentary. API valve standards API 600, 6D refer to ASME B16.34.
API 6A may cover globe valves. The maximum rating covered under 6A is 15000 psi.

 

[terje61]

Hello TMBeau,

The API and ASME standards have in common that they cover pipeline equipment (and valves). However they have a different origin.
The API specifications are focussed on upstream equipment, like wellhead equipment, X-mas trees and subsea piping.
The ASME specifications are focussed on downstream equipment, like separator valves, transport lines and processing plants.
It is possible to design a valve that complies with both specifications, but it is very unlikely that an API valve will always cover ASME B16.34 standards.

Example:
API 6A calculates strength based on material classes (45K / 60K etc.) Wallthicknesses may vary, depending on the material.
ASME B16.34 tells you the minimum wallthickness and then provides tables what the strenght will be at what temperature.

So my advise is to keep the standards separate. Do not purchase an API valve if you need an ASME valve or the other way around. If you are the manufacturer: go through the standards in detail and tabulate the requirements for each pressure class. There is no easy way out.

In general the valve design is not restricted by API. These can be all kind of globe or gate valves. But note that manufacturing valves in accordance with API needs API approval/verification. This may restrict the possibilities.
Example:
At high pressure classes API may require as a minimum 60K materials. If a typical design can not be manufactured in high strength material, you will not find it as API qualified.

Regards,
Terje

 

[bcd]

Hello,

There are two distinct types of API valve standards. Those created by the upstream group for distribution of raw crude and gas which can still contain corrosive and other damaging elements (e.g., sour gas). Those are the API-6A and 6D specifications. The only reference to B16.34 is for design guidance. It is not mandatory.

The group writes standards for valves inside the refineries where typically, most of the nasty stuff has been removed. These are the API-5XX and -6XX series of valve standards. In some of these standards, conformance to B16.34 is mandatory. In those that do, they start with the statement that inaddition to complying with B16.34, the following requirements are to be met.

If you are in the downstream side, in the refinery, you will need the appropriate API-5XX or 6XX standard, and in some cases, it starts with complying with B16.34. They go hand in hand.

 

[reverman]

1. Does the API valve standard cover pressure seal bonnet valves?

No. At one time it did cover pressure seals however it was removed from the standard. It is currently being considered at API to put back in for the next revision

2. It appears that API standards do not cover globe valves. Is this true and if yes, why?

Globe valve usage in the petroleum industry historically is very low so no standard was made. A globe valve standard is currently being developed by an API committee but I'm not sure how long it will take to be published. API 602 does cover globe valves for small forges products

3. What is the maximum ASME class allowed by API? I know for B16.34 code valves, the maximum is class 4500

API 600 only covers up to 2500.



4. Can a valve built to API standards by default satisfy ASME B16.34 requirments?


For the most part API 600,602, and 603 valves will by default meet the requirements of B16.34 standard class. Possibly API 6D as well but to be honest I am not very familiar with API 6D products


5. Does the API standard cover all gate valve designs or only certain kinds?

API 600 covers bolted bonnet cast steel (alloy steel) wedge gate valves 2" - 24", Pressure seals and parallel slide valves are not covered