Podcast: What is a Control Valve’s Fail Position? Episode #1


In this first episode of the Stuff You Should Know about Oil and Gas Podcast, Kyle Andrews, Product Applications Trainer at Kimray, explains control valve fail positions, including fail closed and fail open.

Topics in Control Valve Fail Position

  • What is a valve fail position?
  • Does fail position affect operation of oil and gas separators and other production vessels?
  • How should you set up a back pressure valve to fail?
  • How should a pressure reducing regulator fail?
  • At the 8:10 mark, we discuss converting a High Pressure Control Valve from fail open to fail closed. For more information about that, see our step-by-step video

Resources and products mentioned in this episode:

Transcript

Curtis: We’re doing our first ever Kimray podcast, so I’m pretty excited about it. Kyle is an account manager at our Oklahoma City Kimray sales and service store. Very knowledgeable guy, so that’s why he’s here. And he was the first person to say yes. It’s our first episode and so I just wanted to talk for a second about why we’re doing a podcast. The Kimray marketing department, we produce a lot of blogs and website information. We do videos every month and we’re really passionate about sharing knowledge. We have a lot of fun guys here who are really knowledgeable and have a lot of experience. And so we think it’s good and healthy for the industry if we share that across companies.

So, this is just another medium that we wanted to share some of that information and so hopefully maybe a little safer one if you’re in a truck and you want to listen to something, this could be a helpful thing and you don’t have to watch a video or read something that’s not safe to do while you’re driving. So, let’s go ahead and get into it to Kyler, our first episode, we want to talk about our valve failure position. This is a blog that tracks pretty well on our website. So obviously a lot of people have questions about it and want to make sure they’re getting this right. The question is, should my valve fail open or closed or in place? So real quickly, what if we’re talking about failure position? What type of valve are we talking about?

Kyle: So, we’re talking about control valves.

Curtis: Control valves. Okay, so does that have to be a high pressure?

Kyle: Does not have to be a high pressure or low pressure control valves also have a failure position.

Curtis: Okay. Alright. So, what’s the difference between fail closed and fail open?

Kyle: Fail closed would be if you have no motive gas going to the actuator.

Curtis: What is motive gas?

Kyle: Motive gas or anything energizing the actuator. So, whether you have a pneumatic actuator or even an electric actuator, it’s the thing driving the actuator to a position. If you take that away, the fail position is going to be the position that the valve ends up in. So, with a fail open valve, if you take away the pneumatic signal going to that actuator, it’s going to fail open. The pneumatic signal going to the actuator closes the valve without that signal, it fails open.

Curtis: Okay. So, every valve is either fail open or closed.

Kyle: Yes. you can get those control valves in. You can order them, fail open or fail closed. They’re also convertible, especially our high pressure control valves. Our field convertible are easy to switch from fail open to fail close.

Curtis: We made a video about that once.

Kyle: Yes, we did.

Curtis: Ok, also there’s some language that I’ve come across like pressure open, pressure close. Is that same thing?

Kyle: Same thing, it’s just different way of saying it. Fail open is the same thing as a pressure closed. Pressure closes it and so without that pressure, it’s going to fail open. Or you could say fail close is the same thing as pressure open.

Curtis: Okay, so when that pressure’s pushing on it, then it can close. So, if I’m a producer at any level, I’m trying to figure out which type I need to order. How do I make that determination?

Kyle: Well, it depends on the application and you’re using it in. As if you’re using this as a dump valve, you could be using it as a pressure regulator. Our control valves can be used in a variety of different applications. So, you need to determine what you’re going to use it for, and then that will help you determine if you need fail open and fail close.
Okay, for example if you’re using this as a back pressure regulator with a pressure pilot the standard orientation would be fail open. So you’re holding back pressure on a piece of equipment. If that valve fails and something goes wrong, you want that valve to open.

Curtis: You don’t want pressure building up behind it.

Kyle: Exactly, you want it to relieve that pressure. So the standard set up for a back pressure package is fail open. If that valve fails, it’s relieving the pressure on the piece of equipment that it’s holding that back pressure on. It’s because you don’t want that back pressure to continue to increase if the valve is failed closed.
And that could be bad.

Curtis: Okay, I have a question about equipment again. High pressure or low pressure pneumatic, what about the back pressure valve? Could it be either?

Kyle: It could be either. Our standard is to build those packages as fail open.

Curtis: Okay. So even the AAR then?

Kyle: The low pressure regulators don’t necessarily have a fail position. Because they’re not a control valve it’s a regulator. Its’ works a little bit differently.

Curtis: Ok, if they lose a signal then?

Kyle: Well they won’t necessarily lose a signal.

Curtis: Because its’ all incorporated in one thing?

Kyle: Correct, it’s integrated and maybe we can do another podcast over that cause it’s kind of getting down into the nitty gritty.

Curtis: Alright, we’ll do another podcast. So, in a dump valve application, what would I want?

Kyle: Fail closed and if something goes wrong with the level controller that’s opening and closing the dump valve and if something were to go wrong then, normally you’d want that to fail close. That way you’re not draining the vessel of liquid and then blowing gas down the liquid lines.

Curtis: Okay, so I’d want that liquid to just stay in the tank until I can address the problem.

Kyle: Yes and separation equipment will have a high level shutdown sensor on it. So, if the valve dump valve fails and goes closed, liquid level will continue to rise in the vessel until it hit that switch and then it would shut the incoming liquid down where it’s coming into the vessel upstream.

Curtis: Okay if we’re sketching out some different applications, so dump valve, fail close, back pressure, and fail open.

Kyle: Yes, pressure reducing is going to be a fail closed because you’re monitoring downstream of the valve, so that’s what you’re wanting to protect. So if something goes wrong with the valve, you want it to fail closed. That way you’re saving that piece of equipment that’s downstream. All in a pressure reducing application. Back pressure would be fail open while PR or pressure reducing is fail closed.

Curtis: Okay, we said we could change that in a high pressure situation or hybrid control valve. You could flip those top works and change it?

Kyle: Yes. you can change the fail position.

Curtis: Do that people do that regularly?

Kyle: Yeah, if they’re taking a valve that they’ve used as a dump valve and they want to convert that valve to a back pressure package, they’re going to have to swap the failed position because the dump valve is going to be fail closed, but then you want the back pressure package to be fail open.
So, you’d have to change the top works. And you don’t have to buy new valve, you just flip it. When people are repurposing valves, it’s really handy to be able to change field position.

Curtis: Would they get a repair kit if they do that?

Kyle: I would if you’re already going to have the valve out of service. It’s a good time to put a repair kit in it and make sure that it’s functioning well.

Curtis: Okay, so any common problems, challenges you see, confusion about this idea of fail open, fail close?

Kyle: Yes, I actually had a customer reach out and he needed a back pressure package. I tested the pilot, the valve, and I did some sizing for the trim set. He didn’t want us to build the package for him. He just wanted the components. So he ordered all the components and had everything tubed up. It was about a week after he got the parts, he called me and said, this back pressure package is not working. It won’t open at all. And I asked him if he could send me some pictures. Eventually he sent me pictures later that day.
When looking over the pictures, I instantly saw what was incorrect. He had the failed position of the valve incorrect.

Curtis: So, you could just see that by how it was tubed up?

Kyle: Correct. He had, it backwards. He had it where it was trying to fail closed. So, pressure was trying to open the valve. The signal from the pilot was trying to open the valve. The issue was the pilot he was using was an indirect pilot, which is our standard pilot for all pressure regulating packages, but he had the failed position of the valve incorrect. So, he had it failing closed when it needed to be fail open.
And there’s a couple of things that he could have done to make this work. He could have either flipped the failed position of the valves by flipping the top works, or he could have changed the action of the pilot. It was an indirect pilot, so he could have changed it to a direct pilot. Which would have made that package a fail closed back pressure package. Either one would have worked. I went ahead and told him just to change the top works over and then put the output of the pilot to the other side referring to the actuator. And he did that and it worked just fine.

Curtis: Ok great work! So, what about failing in place?

Kyle: In terms of pneumatic actuators, like we’ve been talking about, there is no fail in place. That’s more on the electric actuator side. So, with pneumatic actuators in pneumatic top works, the spring is what makes it go to that failure position.
So there’s no way to stop that spring halfway in it’s travel, or if it’s traveling open and the valve fails. That spring’s going to push it all the way one direction, whether that’s fail open or fail closed.

Curtis: Okay so an electric actuator, you can either stop where it is or….?

Kyle: Correct, if your electric actuator has a battery backup and let’s say you lose power as long as it has that battery, it can go to a known position or the last signal that it received. If it received a signal saying, I need you to go halfway open and that’s the last thing it got, then it’ll stay there. Then you can also have it fail all the way closed or all the way open.

Curtis: Okay all right Kyle, so key takeaways on applications again where you would use fail close, fell open. Can you walk us through that?

Kyle: Yeah, so a liquid dump valve is going to be a fail closed. Pressure reducing valves like a suction control valve on a compressor is also going to be fail closed and back pressure valves are going to be fail open.


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