Pipeline Valve Compliance: API 6D Testing

Do you have spare valves in your lot that you’re planning to install on your pipeline? If so, how long has it been since those valves have been tested to API 6D specifications?

If you’re in the oil and gas industry, you’re probably very familiar with API 6D, the standard that provides specifications for ball, check, gate, and plug valves used on pipelines. API 6D testing is required by the Department of Transportation for all pipeline valves. Not only that, but if an accident happens, both the DOT and the EPA will want to see the test records to assess whether your valves are in compliance.

When to perform 6D testing

All valves installed on pipelines must be tested to 6D standards. In other words, it doesn’t matter the application — if a valve has an API stamp, it must have supporting paperwork.


Crane loading ball valves

Here are some common situations when you’ll need to have your valves tested:

  • When you’re recommissioning a pipeline. Over the past few years, pipelines that were decommissioned have started being recommissioned. Since the valves on these lines have often been idle for years, they need to be reconditioned and tested.
  • When you’re installing spares that have been sitting around for a while. If you’re replacing a valve on your line with a new one that’s been sitting outside for more than a year or through extreme weather changes, you’ll want to test it before installing it into the line.
  • When you’re using a valve in a bypass while you perform maintenance. Technicians will often put in a valve in a bypass pipeline while they perform maintenance on the main line. If these bypass valves have been sitting for more than a year or have experienced extreme weather changes, they should be tested before installation.
  • When you send a valve in for repair. Any time you have an API-stamped valve repaired (e.g., because it’s leaking or not functioning correctly), the valve must be retested before you put it back into service on your line.


Semi truck with ball valves

What API 6D testing entails

There are three types of tests required under API 6D:

  • Stem backseat test
  • Hydrostatic shell test
  • Hydrostatic seat test

For valves up to 16” x 300 lbs, we can perform these tests using our Barbee TF 100-DAQ test stand. We have tested up to 24” 900# in the shop, and we can test larger valves with bolt-on flanges into the valve.

A complete test takes about 8 hours from start to finish. The majority of that time is devoted to the hydrostatic shell test, which the DOT requires to be held for 4 hours.


Ball valve on Barbee test stand

Here are some common questions we get about 6D testing:

  • Can you hold the tests for longer than the API specifies? Yes. Many companies have more stringent internal requirements, so they request longer tests.
  • Will the test be charted? Yes. We perform charted tests and can provide graphs showing pressure, temperature, and duration (see image below).
  • What media do you use? We can use whatever media you require. Companies often ask us to use oil-based media, put antifreeze in the water, or even use water wetter.
  • Can you do an air test? Yes. We perform air tests at a lower pressure than for liquid tests.
  • If you bolt flanges into the valve, what torque do you use? The torque values are determined by the bolt size.

In short, we can perform testing based on your requirements, whether that means just meeting or exceeding 6D specifications. To learn more about 6D testing, or if you have any questions about our valve services, please contact us.


Ball valve chart testing

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