How to Select the Right Pipe Material for Fluid Handling Operations

At manufacturing plants and other industrial locations, many parts are involved in the success of the entire operation. One of those components is the fluid handling system throughout the building — the piping that runs along the walls, ceiling and potentially underground to provide the facility with water, oil and other fluids that are necessary to complete certain processes.

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Like any system, the pipe and fittings involved in your fluid handling operations will eventually need to be replaced. If you’re building a new facility, you get to start from scratch and choose the best piping material for your needs. Whether you’re replacing your fluid handling system or installing one at a brand-new building, there are several factors you should consider before starting, as well as multiple pipe material options to choose from.

When implementing or constructing a fluid handling system in your plant or warehouse, you will have to make several decisions based on your industry, handled materials and objective. One of the most important decisions you will make during this process is the type of pipe material you need to transport your liquids, gases, chemicals and other fluids. This is not a decision to make lightly — the wrong pipe material could jeopardize the quality of your product, as well as the safety of you and your employees.

Here are seven factors to consider when choosing the best pipe material for your fluid handling system.

8 Elements to Consider When Selecting Pipe Material

The material of the pipes in your fluid handling system has a direct impact on the overall success of the system, as well as your facility’s overall mission or goal. It’s critical to weigh all your options and account for the multiple factors that will affect the oil and water pipe material selection process. Here are eight things to consider before you choose your fluid handling pipe material.

1. Material Being Transported

What type of liquid are your pipes transporting? More specifically, is the liquid corrosive or non-corrosive? Corrosive liquids include substances such as crude oil, ammonia, seawater and other acidic liquids that have a heavy chemical makeup. These liquids require a corrosion-resistant pipe material such as a plastic CPVC pipe or lined pipe. Since most liquids are at least slightly corrosive, you will need a corrosion-resistant material for the pipes that will transport it. Meanwhile, non-corrosive fluids or gases like lube oil, air and nitrogen are safe to transport via carbon steel or metal pipelining.

The type of liquid or gas your pipe system transports plays a significant role in choosing fluid handling pipe material. Some pipe materials are better suited for non-corrosive liquids, like oils or standard wastewater. More corrosive liquids, like acid or peroxide, require a pipe with an interior that can hold up to the abrasiveness of these corrosive materials. Corrosive materials are common in many industrial cleaning solutions, as well as in chemical manufacturing and handling. Remember, despite a plastic or metal pipe material’s durability and corrosion resistance, chemicals, acids and saltwater are much more abrasive than standard water or oil. Always keep the liquid you are transporting in mind when selecting a pipe material.

Take a look at how the following popular pipe and pipe lining materials stand up to corrosion:

• Stainless steel: It’s called “stainless” steel for a reason — stainless steel does not rust or corrode as quickly or easily as other materials. It naturally resists most corrosion because it consists of several different alloys, all of which help form a protective oxide layer on the surface. This natural layer is tough and durable. For this reason, it is an ideal water pipe material selection that is also suitable for oils and some chemicals.
• Aluminum alloy: Aluminum does not rust, which is useful when you need your transported liquid to remain pure and uncontaminated. It can handle exposure to many gases, oils and liquids without deteriorating. However, aluminum does corrode over time, especially in saltwater or sulfuric applications.
• Cast iron: Cast iron is easy to find and is uniquely durable against many external sources of corrosion, like plant growth and soil, because it is so thick. Cast iron can withstand water and saltwater for short periods, so it could be suitable for short-term projects. However, it does corrode and rust after prolonged water exposure.
• Fluoropolymer (PTFE) lining: PTFE pipe lining is non-reactive and very resistant against corrosive chemicals. It is one of the most universally applicable pipe lining materials, and thanks to its durability and zero-risk of product contamination, it is the perfect acid, water, chemical and oil pipe material selection.
• PVDF Kynar® lining: PVDF pipe lining is very durable and strong, and is one of the most abrasion-resistance materials on the market. Manufacturing facilities or plants that handle high-strength acids, chemicals, saltwater and nuclear materials find success with PVDF lining. It also resists corrosion from natural sunlight and weathering.
• Galvanized steel: For short-term saltwater projects, galvanized steel is a suitable pipe material, as it does not rust. However, it will corrode after prolonged exposure to both salt and water. Also worth noting is that galvanized steel often corrodes from the inside out, so it may be challenging to detect.
• Copper: Copper is widely used due to its ready availability and aesthetic appeal. It is not completely immune to corrosion, but it is more corrosion resistant than many other materials, such as galvanized steel. Copper is most prone to corrosion in fresh and saltwater, as well as particularly harsh chemicals and acids.
• Resistoflex ATL PTFE lining: ATL PTFE pipe lining contains specially formulated resins that make it very strong and durable during prolonged exposure to saltwater and aggressive chemicals. It is often used in paper processing and power generation plants, as well as in the service industry.
• Carbon steel:  Although carbon steel is ideal for high-temperature fluids, it does corrode easily under high levels of exposure to moisture, chemicals and acids.
• Polypropylene (PP) lining: PP pipe lining is a good high-temperature pipe material as it performs very well in temperatures as hot as 225 degrees, as well as saltwater and both basic and acidic applications. However, it does not withstand solvents, volatile organic compounds (VOCs) or excessively low temperatures. PP lining is often used in water treatment facilities, chemical processing plants, power generation facilities and food and beverage manufacturing.

2. Temperature of Liquid Passing Through

The next thing to consider is the temperature of the liquid in your fluid handling system. If you’re transporting high-temperature liquids, you’ll need to be sure your system consists of high-temperature pipe materials. Certain types of plastic piping may not be ideal for handling high temperatures, while others may be designed to handle fluids no matter how hot they are. Metal pipe materials are typically wise choices for high-temperature liquids, although some types may become too hot to the touch.

If you are handling extremely high or low-temperature fluid — including cryogenic liquids— make sur

e your pipe consists of material intended for extreme temperatures. Otherwise, you risk damaging or corroding your pipes and contaminating the liquids inside of them. In some cases, extreme temperatures can break your piping entirely, resulting in expensive repairs, damaged product and hazardous workplace conditions. Metal pipe material is usually suitable for extremely hot liquids, although you and your employees should exercise caution when working with them. Depending on the temperature, aluminum is often used to transport cryogenic liquids.

Your piping material must support these temperatures as well as maintain them throughout the liquid transfer process. In many applications — including laboratories, food processing, medical facilities and plants that work with hazardous chemicals — precise temperatures are required for all liquids and vapors used.

Some pipe materials that can be suitable for high temperatures include carbon steel, as well as PTFE, PVDF, ATL PTFE and PP pipe linings. For extremely low temperatures, copper, some aluminum alloys and high-alloy austenitic stainless steel are least likely to become brittle and break.

3. The Pressure of the Liquid Handling Process

What is the pressure of the fluids your system is handling? If the pressure of these service fluids is very high, you will need piping material that is either high-strength, higher thickness or designed to resist high-pressure fluids. The average pressure that most manufacturing facilities’ piping must be able to handle is around 150 pounds per square inch gauge (psig). If your facility is working with liquids of higher pressures than this, you may have to request a piping material that is specially designed to handle high-pressure fluids.

Various liquids and gases create different pressures inside of your fluid handling pipes. For example, cryogenic fluids are known for creating very high-pressure environments during the transfer process. Many external factors can impact this pressure, too, including the temperature and elevation of your piping.

Some liquids and gases that might require pressure-specific pipe materials include:

• Ammonia
• Chlorine
• Propane
• Carbon dioxide
• Nitrous oxide
• Acetylene
• Butane
• Hydrogen
• Helium
• Neon
• Nitrogen
• Concentrated oxygen

Make sure you choose a pipe material that is rated for high-pressure or low-pressure substances and conditions. If you use a high-pressure liquid or gas in a pipe that is not suited for high-pressure handling, you risk leaks, pipe bursts, flooding, fire, explosion and injury to property and personnel.

Never assume your fluid handling system is adequate for high-pressure substances. Always ask your pipe provider if your fluid handling system is designed to handle high-pressure fluids and vapors before use.

4. Service Life of the Fluid Handling System

You need reliable and durable piping, but how long do you need your fluid handling system to last? A major component of effective piping design and material selection is asking how long you expect your fluid handling system to last. If you know you’ll likely have to replace the system in five to 10 years due to another reason, such as relocation, you don’t need to invest in a very long-lasting piping material. This may also affect how much money you’re willing to spend on the system, which will, in turn, impact the type of material you should choose.

If, on the other hand, you expect this system to last for 10 or more years, you should invest in the most durable type of piping material.

For example, temporary worksites or processing plants that do not typically deal in fluid handling may not need as intricate or durable a system as a permanent plant that transfers fluids daily. You should also factor in how often your business will use your fluid handling system. Of course, there are some conditions — such as extremely corrosive chemicals, hazardous materials or fluids that need temperature regulation — that will require certain pipe materials, regardless of the desired service life of your system. If no special circumstances apply to your business, use this information to help you gauge the amount you should invest in your pipes, as well as that type and quality of material used.

5. Ease of Maintenance

Just like flooring, countertops and other solid surfaces, certain types of piping material are easier to clean than others. Ask yourself how often you can clean your fluid handling system. Be realistic about the frequency, as it is can become a very time-consuming task depending on the size and intricacy of your system. If you won’t be able to clean it very often, having a low-maintenance piping material should be a priority for your facility.

Make sure the material you choose for your fluid handling pipes is maintainable under your current circumstances. There are three main types of maintenance that all fluid handling systems should consider:

• Preventive maintenance: Preventive maintenance is necessary for all parts of your fluid handling system, and should be performed at regularly scheduled intervals based on the approximate cost of downtime, potential risks of system failure, expected time between part repairs and availability of backup equipment if necessary.
• Routine cleaning maintenance: Routine pipe cleaning maintenance will help prevent internal and external product build-up, which can corrode your system and contaminate transferred fluids.
• Emergency maintenance: Even with attentive preventive maintenance and highly durable products, you will likely require emergency or special repairs at least once in your fluid handling system’s life. Address concerns as they arise to reduce emergency maintenance visits.

During each of these maintenance scenarios, your pipes must be accessible. Always have a professional technician install your fluid handling system. Professional system technicians are trained to consider your system as a whole, rather than focus on singular parts or pieces of equipment. They will make sure your pipes are large enough for your space and business needs, but not oversized. Oversized pipe systems result in unnecessary maintenance and take up a lot of otherwise usable space.

If your business does not have the time, available workforce or budget for regular and frequent maintenance, choosing a low-maintenance pipe material should be your top priority.

6. Exposure to External Elements

External elements exist indoors and outdoors. Indoors, external corrosion and other issues can arise from corrosive fumes in the air, humid conditions and mold. Outside poses several threats for external corrosion and damage, including the salt in seawater, inclement weather, microorganisms, plant overgrowth and more.

If any part of your fluid handling system is exposed outdoors, you need piping material that can withstand environmental elements. External elements that could lead to the deterioration or corrosion of your fluid handling piping include UV light, corrosive soil, precipitation and other atmospheric conditions.

Examples of external elements to be cautious of include the following:

• Corrosive fumes or vapors in the air from other work stations or materials
• Extreme or fluctuating temperatures, both indoors and outdoors
• Mold and mildew growth
• Salt from seawater
• Inclement weather, including rainfall, snow, lightning and hail
• Micro- and non-microorganisms that can burrow or corrode
• Plant, root and moss growth on outdoor piping
• Exposure to UV rays from the sun
• Corrosive and damp soil

7. Valve and Fitting Sizes

Certain piping materials will only have a few valve and fitting sizes to choose from, so you may need to eliminate some options based on this factor. Some of the valve and fitting types you can choose from include:

• Butterfly valves
• Ball valves
• Check valves
• Diaphragm valves
• Rupture pin safety valves
• Knife gate valves
• Solenoid valves
• Slurry valves
• Severe service valves
• Sanitary valves

The types of valve and fittings you choose will depend upon the types of connections you’ll need to make from pipe to pipe, as well as to connect the pipes to other features of the fluid handling system.

8. The Cost of the Material

Cost is a significant factor in any business decision. As you consider different pipe materials, keep in mind the cost of:

• The initial investment in all required parts, including the pipes, valves and pipe fittings
• Whether your chosen material is readily available or needs to be imported
• Routine and emergency maintenance appointments
• Pipe lining materials, if applicable

As with any expense, always consider the return on investment when comparing different costs. For example, if a pipe material is best suited for your industry due to its thermal regulation and durability, but it is more expensive, keep in mind the potential loss you might face if choosing a cheaper, less viable option. For many industries, not investing in the right pipe materials can lead to much more costly issues down the road. Always keep your industry’s non-negotiable needs in mind when examining costs.

Types of Piping Material Available

Now that you know what factors will affect the piping material you should choose, let’s talk about six of the most popular piping materials, as well as the conditions that each of them would work best for.

1. Cast Iron

Cast iron was one of the earliest materials used for piping, and it’s most commonly found in underground applications. Piping that carries materials like water, gas and sewage underground must be incredibly durable, pressure-resistant and long-lasting since these pipes must last for several decades without having to be replaced. Soil pipes are also commonly made using cast iron due to its excellent corrosion-resisting properties. Cast iron pipes are more popular in apartment buildings rather than private dwellings due to its fire resistance and noise-dampening qualities.

If you need underground piping at your facility that will last as long as possible, cast iron may be the best material for your fluid handling system.

2. Steel and Steel Alloys

Carbon steel pipes and steel alloys are created using different manufacturing methods to provide multiple piping material options all made from steel. Steel is a desirable piping material because of its thickness and ability to contain highly pressurized fluids. Two common types of steel piping materials for manufacturing facilities are:

• Carbon steel pipes: Carbon steel pipes are available in several different grades depending on the amount of carbon the pipe contains. This type of steel piping is more subject to corrosion than other varieties, making it ideal for indoor systems transporting non-corrosive materials.
• Galvanized steel: The second option for steel piping is galvanized steel, which is better equipped to handle corrosive fluids, as well as high-temperature materials. However, it is not as ideal for high-pressure substances, as it is rated only for pressures of up to 250 psi.

3. Nonferrous

The category of nonferrous pipe materials refers to any piping material that is a metal other than steel. Popular options for nonferrous metals include:

• Brass: Brass piping is popular for the transportation of corrosive materials, and the most common type is red brass.
• Aluminum: Several varieties of aluminum piping exist based on the type and amount of alloy added to the aluminum. The level of aluminum pipe you choose will be dependent on whether you’re transporting highly corrosive or high-pressure materials.
• Copper: Copper piping is standard for both commercial and residential water applications, such as plumbing and other waterlines. You can choose between several types of copper piping based on thickness.
• Copper-nickel: Copper-nickel piping is most commonly used in marine and offshore applications for its excellent ability to transport seawater effectively and with minimal corrosion. As a durable pipe material option, copper-nickel can also handle materials of high temperatures.

4. Concrete

The most typical application for concrete pipes is in large-scale engineering projects such as water resource management and stormwater control. Depending on the diameter of the pipe, concrete pipes are typically reinforced with another layer or durable wire to allow it to maintain its strength underground. Concrete pipes used for civil purposes must pass several destructive tests to ensure they can withstand any potentially disastrous occurrences.

These pipes must also be regularly maintained, as dirt and debris can easily stick to the insides of concrete pipes and cause a backup. Depending on the type of material the pipes are carrying, a sewage or stormwater backup could be very hazardous to the surrounding areas. Most manufacturing facilities would not benefit from using concrete piping for their fluid handling systems.

5. Plastic

Plastic pipes are an option you may seriously consider for your facility’s fluid handling system. Options for plastic pipes include:

• PVC: Polyvinyl chloride (PVC) pipes are the most widely used type of plastic piping, ideal for both structural and electrical applications.
• Polypropylene: Polypropylene pipes are most effective and appropriate for transporting chemical waste and other highly corrosive materials.
• Polyethylene: Polyethylene is a flexible but strong material that is best for piping in irrigation, sprinkler and other water-related applications.
• PEX: PEX pipes are essentially polyethylene pipes that have been processed to be both stronger and more resistant to hot and cold temperature changes. This material is becoming a significant alternative to traditional copper pipes.
• ABS: You’ll find ABS pipes in sewer, waste, drain and vent applications.

6. Lined Pipe

We saved the best type of pipe for most industrial and manufacturing systems for last — lined pipe and fittings are recommended for fluid handling systems in most facilities. Plastic-lined steel pipe is essentially the “best of both worlds,” combining the corrosion-resisting qualities of plastic with the durability of metal materials. You can choose which type of plastic material you want your steel pipes to be lined with. Popular choices for plastic-lined pipe and fittings include:

• Polyvinylidene Fluoride (PVDF): When you’re transporting high-strength acids and other corrosive liquids, opting for PVDF-lined pipe and fittings is a durable choice. These pipes are designed to withstand the corrosive properties of fluids involved with chemical processing and electronics manufacturing.
• Fluoropolymer (PTFE): PTFE-lined pipe and fittings are known for their ability to transport fluids at high temperatures and pressures. Its strength and corrosion-resistance make it a popular piping material for many industrial applications.
• Polypropylene (PP): PP-lined pipe is the best choice for handling basic fluids with low chemical makeup and low to no corrosive qualities. It’s the most economical option for small-scale operations and transporting liquids at an average temperature.

Benefits of Adding Thermoplastic-Lined Pipe to Your Operation

For most standard manufacturing facilities and other industrial applications, there are several benefits of plastic-lined pipe and fittings. Some of the most notable advantages of this type of pipe material include:

• Affordability: By combining the excellent resistance properties of plastic lining to the low cost of steel and other metallic materials, thermoplastic-lined pipe and fittings are one of the most affordable piping options for many manufacturing facilities.
• Customization: By adjusting the amount of each material used, you can customize the properties of your lined pipe while still benefiting from each material’s most desirable characteristics.
• Safety: Plastic-lined pipes lead to improved product quality thanks to the lack of contamination from the liquid touching metallic materials. They are also less likely to result in the fouling of materials and the costly downtime that comes along with the cleanup and repair process.
• Lower maintenance: Thermoplastic-lined pipe is resistant to corrosion and chemicals, and it also does not require frequent maintenance or cleaning.
• Simple installation: When installation technicians have been trained properly, lined pipe installation is much simpler, faster and affordable than installing metal pipes.

Which Pipe Material Is Best for Fluid Handling Operations?

To find the best pipe material for fluid handling operations, you must consider several factors about your facility and your fluid handling system. Every manufacturing facility is unique and requires pipe material and fittings for differing applications. When it comes time for you to replace your fluid handling system, be sure to consider each choice carefully and not just do what everyone else may be doing. Just because metal pipe liners work for one facility, for example, does not mean they are also the best choice for yours.

That being said, lined pipe material is often the best solution for most average-sized manufacturing facilities, as it combines the best features of the two most popular small-scale choices — plastic and metal.

Get Custom Pipe and Fittings From SEMCOR

Once you’ve decided which pipe material and fittings might be best for your operation, contact the experts at SEMCOR to start the process of getting them into your building or buildings. We offer the best products for custom fluid handling, including pipe and fittings, valves, hoses and other custom solutions. Plus, all our products are designed with durability in mind, minimizing the need for future maintenance or an early replacement. We can also provide assistance in choosing the right materials based on your facility’s system and needs.

SEMCOR offers a wide range of fluid handling solutions and customizations, including:

• Pipe and pipe fitting fabrications: SEMCOR specializes in rigid piping designed to withstand high-temperature and corrosive environments. We also provide high-quality and standard plastic pipe linings and fittings, including PTFE, ATL PTFE, PVDF and PP lining. If you require custom lining and fabrications, SEMCOR is here to help.
• Hose and valve modifications: SEMCOR offers hoses made of PTFE, metal, rubber and plastic. We also provide PTFE hose crimp fittings, rubber hose clamping fittings and metal hose welding fittings, so each product can be modified to meet your exact specifications. Our valves, actuators and controls come from top industry suppliers and are made of strong, corrosion-resistant plastics so they can withstand the most abrasive fluid transfer. Our design and fabrication options also allow us to create customized valves, actuators and control solutions for any industrial application.
• Custom expansion joints: SEMCOR provides customizable metal and rubber expansion joints from top industry brands like Resistoflex and Hose Master.

Since , SEMCOR has remained committed to answering your questions and delivering nothing but top quality fabrications for your business. To learn more about SEMCOR fluid handling products and services, or to request a quote, reach out to us online or at (314) 300-.

Looking for control valve installation best practices?

Below we'll cover 7 things you must do when installing a high pressure control valve.

1. Don't Hold the Control Valve by the Tubing

Tubing often looks like the perfect handle to lift a valve. However, lifting the valve by this method can quickly bend the tubing itself or the connection point where the nut and ferrell are. And if you bend it too much it can break that seal to the valve.

The best way to pick up a control valve is either by the valve body itself, the topworks or the lifting hooks on the top.

2. Install Isolation Ball Valves

The second best practice is to install ball valves on both the upstream and downstream side of the control valve.

When it's time to do maintenance on a valve, you will need completely cut off any pressure on the upstream and downstream side. This process is referred to as the double block and bleed procedure, and ball valves make it easy to do.

3. Mount the Control Valve Vertically

We often get asked if customers can mount their through-body control valve sideways.

Normally for a through-body valve, the inlet and outlet piping should be horizontal.

However, sometimes, depending on construction of the vessel, the piping the valve is to be installed on is vertical, so if you install the valve without adjusting the piping, the valve would be sideways.

We do not recommend you do this. Here's why.

If you mount the valve horizontally, the weight of the topworks internals and the valve trim pushes the valve stem onto one side of the packing. Because of this, over time you will experience premature wear on the packing and valve stem that could potentially lead to leaks in the valve.

Mounting a HPCV sideways does not allow the lubricating oil on the topworks to travel to the stem. This expedites the wear on the upper stem.

The best practice is to install the valve in vertical orientation so it looks like it's standing upright.

4. Check the Fail Position

Check and make sure the fail position of the control valve is correct for your application.

Sometimes we are asked "Control valves should always be in what position?" This is an impossible question to answer, because it depends on your application.

If you are using it for back pressure, you want it to fail open so pressure doesn't build. However, you may want it to fail closed to protect downstream equipment if there is a failure.

The easiest way to check your valve's fail position is to look at the position indicator to see if the valve is open or closed before you have any pressure on it.

• Is it open? Then the valve is set to fail open.
• Is it closed? Then the valve is set to fail closed. 

The good new is if it's in the wrong fail position, you can open up the top works and convert it without having to buy extra parts.

5. Check for Clean, Dry Supply Gas

Wet or dirty gas doesn't always affect the valve itself, but it does affect the pilot or level controller communicating with it. And if device is not working, the control valve won't work properly.

Examine the vent port of the control device (pilot or liquid level controller). If the vent port looks like it has dirt stuck around it, your supply gas is probably wet. After exhausting the wet gas, dirt will begin to stick to the moisture.

If this is the case, move your tubing to pull supply gas from a high and dry spot or consider using compressed air for instrument supply.

6. Use the Star Pattern to Tighten Flange Connection 

When installing a control valve with a flanged connection, tighten the bolts in a star pattern, just like you do on a car wheel.

One side cinched down too much doesn't create a good seal. Also, any time you are replacing a flanged valve, make sure to replace the flange gaskets. Using a damaged flange gasket can lead to issues.

7. On a Threaded Valve, Use Sealant

When installing a valve with a threaded connection, use Teflon tape or pipe dope (or both) on the threads. This helps seal the connection to prevent leaking and protects the threads.

Bonus: Use 2 Control Valves for Dump Applications!

Recently, many producers in the Permian and Mid-Con have begun using 2 High Pressure Control Valves in dump valve applications on their separators.

These producers are seeing decreased down time and reduced operational costs as a result of this method.

This dual dump design provides redundancy, so you don’t have to stop production to perform repairs. The reason is obvious—if the trim from one valve fails, you can isolate it and divert the flow to the second valve.

This solution also allows for greater variability in production volume. You can install two smaller valves rather than one large valve. You can flow both dump valves in early high-volume production. As production rates decline, you can move down to one valve and repurpose the other on a different application.

Seats, seals and O-rings are small but critical pieces for oil and gas control. These elements play an important role in control valves, regulators, and temperature controllers. They’re made from different types of rubber materials, called elastomers.

You may also hear them called soft goods or rubber goods.  

Each material is designed to perform best under certain conditions. Elastomer wear is inevitable, but by selecting the correct material, you can run production longer before the elastomers require replacement. So, how do you know what to select?  

Download our Free Guide to Valve Elastomers

Let's look at three important questions to ask when selecting your oil and gas elastomers, as well as the four primary elastomer materials that we offer in our products.

What to Consider When Choosing Elastomers

A control valve is made of different elastomers, each designed to perform best under certain conditions. There are three primary data points you need to identify in order to determine which elastomer to select for a given application: Operating Temperature, Level of Potential Corrosion, and Level of Potential Wear.

1. Operating Temperature

This one is straightforward: What is the temperature of the liquid or gas flowing through your production process—specifically the temperature the elastomer will be exposed to?

This is the first point you can use to narrow your selection.

Production running at a maximum temperature of 425° F may be limited to a single elastomer option; however, based on temperature alone, a 200° F operating temperature could still use any of these options.

2. Level of Potential Corrosion

Corrosion in oil and gas production occurs when acid gases, such as H2S and CO2, and chemicals contribute to the elastomer and metal deterioration of the production equipment and controllers.

Though elastomers cannot corrode, when their integrity is compromised, it can cause improper valve function, or even total valve failure. This is why the selection of elastomers is so important. 

When you’re dealing with corrosive conditions, you’ll need to consider important resistance rating categories like CO2, H2S and Methanol. Some are clear—such as using HSN for high levels of Methanol, or Aflas® for high H2S presence. Others, like CO2 have similar resistance across each elastomer.

3. Level of Potential Wear.

One cause for elastomer wear (or erosion) is high levels of actuation. This could be from something like a high-producing well where your control valves need to actuate multiple times per minute to control the flow.

The main cause of elastomer erosion, however, is when abrasives like sand are in the flow stream. Sand will quickly wear out internal components and cause further damage to equipment. This is another reason that elastomer selection is so key to production.

4 Types of Control Valve Elastomers

If you are experiencing recurring issues with your elastomers—for example if you’re replacing the elastomers in your valves more than once a month—you probably need to use different materials. Kimray has narrowed down our options to help make the selection easier.

Buna/Nitrile

Buna/Nitrile is a synthetic rubber commonly used in elastomers. It’s also known as Buna-N or Nitrile.

It's good for most applications with a typical amount of wear and corrosive elements present in the production flow. No matter which kit or selections you make, many elastomers across our product lines will likely have some components made of Buna. 

Highly Saturated Nitrile

Highly Saturated Nitrile, or HSN, is a special class of nitrile with more chemical resistance, thermal stability and greater tensile strength. It’s resistant to petroleum oils, ATF, sour gas, amine/oil mixtures, oxidized fuels, lubricating oils, CO2 and low levels of H2S. Another advantage of HSN is its excellent resistance to Methanol injection.

FKM (Viton™)

FKM (Viton™) is the ASTM short form name for fluoroelastomer. Kimray uses Viton™, which is a registered trademark of the manufacturer, but also widely used for the material in general.  

Viton is a great option primarily for higher operating temperatures. However, with those high temperatures, you’ll need to avoid hot water or steam applications, as the material will quickly break apart under those conditions.

Aflas®

Aflas® is the trademark name for a unique fluoroelastomer that is highly resistant to a wide range of chemicals, acids, strong bases, amines, and steam.

Which Should I Use?

Let's contrast a few of these:

Buna vs Viton

Again, Buna is good for most applications with a typical amount of wear and corrosive elements present in the production flow. Viton can operate at higher operating temperatures than Buna. (Note: avoid hot water or steam applications)

Aflas vs Viton 

While Viton can operate at higher operating temperatures than standard Buna, Aflas has many additional advantages.

Aflas is highly resistant to a wide range of chemicals, acids, strong bases, amines, and steam. It also has outstanding heat-resistance and electrical insulation properties, but is proportionately more costly than Buna or Viton. Aflas is typically targeted at special applications such as high levels of H2S, high temperatures, and amine plants.

Signs You Need to Change Your O-Rings

Here are some key indicators that you need to change elastomers from standard Nitrile/Buna to another material:

• The production fluid is high in corrosive materials (for example, you're operating in the H2S-rich Permian Basin)
• You are injecting methanol to prevent freezing
• You have a high-producing well, and your control valves must actuate multiple times per minute to control the flow
• You are repairing your valve regularly (once a month or more)

Best Elastomers for Common Applications

Here are some examples of the ideal elastomer materials in specific applications:

NITRILE/BUNAHSNFKM/VITONAFLASSaltwater DisposalMethanolHighHeatH2SPetroleum FluidsPetroleum FluidsAcidsPetroleum FluidsGeneral PurposeGlycol DehydrationPropane GasolineHigh HeatWaterLow LevelH2SSteamCO2AmineAcidsBases

Free Elastomer Guide

Download our Free Guide to Valve Elastomers

Bending metal tubing is a critical function for pneumatic devices in the oil and gas industry. In this video, we'll equip you best practices, tips, and tricks to ensure that your tube bending and fitting installation is accurate, consistent, and safe.

Equipment Needed

• Hand Tube Bender
• Marker
• Tubing Cutter
• Deburr Tool (may be on cutter)
• Tubing
• Fittings
• Thread Sealant / Loctite
• 11/16” wrench
• 5/8” wrench
• Measuring Tape/Ruler/Protractor (optional)

Fittings

Components

We’ll start by looking at a fitting which includes four parts: the body, nut, front ferrule and back ferrule.

Generally, you don't want to take these apart ahead of time to avoid the possibility of getting any dirt or debris inside. It’s good to know what the parts are, so when you’re putting it together, you know how to layer the components.

For all fittings on control valves and equipment, we suggest using a thread sealant such as Loctite rather than Teflon tape to avoid the potential of any tape getting inside the equipment.

Installing Fittings on Device

We recommend planning out a path ahead of time so you can avoid tubing that crosses paths if possible. Taking some time up front to figure out your paths can save you material and make your bends easier. On our packages, we like to keep all the tubing as close to the valve body as possible to keep it out of the way.

If you’re installing a straight connector, you can fully tighten it when you install it since there’s only one way the tube can go in. However, to give yourself a bit more flexibility, don’t fully tighten any 90° or elbow fittings until the tubing has been installed.

For this high pressure control valve package, we’re going to start by connecting the upstream side of the valve to the sense line.

Apply sealant to the connection. Since it’s a 90° elbow fitting, we won’t tighten it all the way yet.

How to Bend Tubing: 90°

One of the first things you can do on your tubing is make an end reference mark. This mark will make sure you always know which side of the tube is your reference side, which will go to the left of your bender.

This first measurement will be taken from the where the tubing touches the bottom of the nut to the center of where the bend will be. I’m going to use a piece of scrap tubing to get an estimate of where this bend needs to be.

Insert your tube into the fitting, then measure and mark where you’ll make the 90° bend. This mark will be the centerline radius (CLR) or bend radius. CLR is determined by the die size of the tubing benders.

It can be helpful to mark the whole circumference of the tube so that no matter how it’s inserted into the bender, you can still see the line.

You can easily put this tool in a vise as we’re doing to help keep it steady and leave your hands free to control the tubing.

For more information, please visit Fluid Control Solutions.

Lift the short arm of the bender and insert the tube into the jaw of the bender. Align both zero markers on the tool, then adjust the tube until your mark is aligned with the “L” position. For 90° bends, you always align your mark with the “L”. Our reference side is on the left, so that’s why we use the “L”. If the reference side is on the right, you would use the “R”.

Tighten the tube latch and make your bend. The “0” on the arm (or roll support) will be your indicator for the degree of bend you’re making. Pull the arm down until you reach the 90° mark.

Springback

You may need to bend slightly more than your target angle to compensate for angular springback, which is how the tube will spring back a few degrees when released. Don’t over bend it too far—you can always go back and add more, but you can’t reduce an angle after it’s made.

Cutting the Final Length

Now we’ll be cutting our bent tube to length. Insert the tubing in one fitting and make a mark where it aligns with the shoulder of the fitting body.

A tubing cutter works by rotating around the tubing and gradually tightening the cutting wheel until it cuts through the tubing.

Position the mark in the cutter. Turn the handle until the wheel touches the tubing. Then turn the handle an extra 1/16-turn. The marks on the handle indicate an 1/8-turn, so use that as a reference.

Rotate the cutter around the tube. After every second rotation, turn the handle about a 1/16th of a turn until the tube is cut through.

Deburring

After cutting the tubing, use a deburring tool to remove any sharp edges or burrs from the tubing. This is an important step to ensure that the tubing fits securely into the fittings without causing any damage.

Install Tubing and Tighten Fittings

To keep track of the amount of rotation, you can mark the tubing and nut in its starting position. Hand-tighten the nut and then turn another 1 or 1-¼ turns with a wrench. Overtightening can put too much pressure on the fitting. Do this for both fittings.

How to Bend Tubing: Two 90°

Fittings & First 90°

For our second connection, we’ll be using a straight connector and one elbow. First, apply sealant to the connection. Fully tighten the straight connection then hand start the elbow connector leaving a half turn to make the installation easier later.

For this piece of tubing, we’ll need two 90° bends. Measure to get a rough estimate of the length of tubing you’ll need.

Cutting a long piece of straight tubing is difficult to hold on to while cutting, so you can lightly put it in a vise if you need. We’ll do a final length cut later.

A quick trick you can use to get measurements for a bend like this is to use your tubing set in the connector and some scrap tubing in the other connector. Line them up by eye and use a straight edge or a level to get a more accurate measurement. Make your mark on the center line.

Using the same techniques as the other bend, insert the tubing, align the zeros and put your mark at the “L”. Clamp down with the latch and bend to the 90° mark.

Second 90°

For our second 90° bend, accuracy is more important now because we must reach our fitting perfectly. Return the bent tube to the fitting, and slightly move the scrap piece of tubing so it can rest in its final position. Mark the center line on your tubing for your second 90° bend.

Before clamping the latch down all the way, make sure that your tubing bender is square with the bend you previously made. Check the level of the tool, then check the level of the previous bend.

Secure the latch, bend the arm down to bring the zero to the 90° indicator, maybe a little more, then release.

With the tubing back in the fitting, mark the final length based on the start of the shoulder of the fitting body. Make your cut, again tightening after every second rotation. Deburr the end and you’re ready to install.

Hand-tighten the fittings, mark a reference point and turn 1 to 1-¼ turns.

How to Bend Tubing: 90° & Offset

On this example, we’ll be making a 90° and an offset bend.

First, we’ll measure for the first 90° bend. Use a piece of scrap tubing in one fitting and your actual tubing in the other. Use a level to mark where your centerline will be.

The length of tube before our mark is less than the allowable amount for this tubing bender. Since we know we will need the shortest amount of tubing possible before the bend, I’ll simply adjust it so the reference end of the tubing is aligned with the latch.

A best practice when you’re making two bends on a single tube is to make a reference mark on the top of the tubing, so you get the correct orientation of the bends.

Set in a scrap piece of tubing and measure the distance from the center line of the scrap piece to the center line of the fitting. In this case, 3”.

For this piece, the offset just needs to clear the bonnet or any obstructions. Make your mark and bend the tube, but for this bend, we’re not bending it to a certain angle, we’re bending it to achieve that 3” offset height.

For this bend use the mark you made earlier to help you align the tubing correctly for your next bend. You’ll need more precision on this second bend, so use a level to get your angle correct. Tighten the latch and make your bend.

This might be a little bit of a trial-and-error process, just don’t bend it too much. Bend it close, get a measurement and adjust from there.

The reason we’re doing it this way instead of mathematically is because it’s just not necessary for the type of connections we need to make here.

If you want to calculate the exact distance for an offset with two 45° bends, multiply the offset height by 1.414. That will be the length of tubing needed between the two centerlines of both 45° bends.

With our offset bend ready, mark the final length of tubing near the shoulder of the fitting. Make your cut and deburr the end. Once the piece is in place, make reference marks on the fittings and tubing to fully tighten the connectors.

How to Bend Tubing: Two 90° Plus

For this connection, we’re going to use two straight fittings. The tube will have two 90°s. We’ll start by fulling tightening the fittings using sealant.

Take a rough measurement of the amount of tubing you’ll need. Each side will need to come out of the fitting and make a 90° bend.

Set the piece of tubing in the fitting and a scrap piece in the other. Use another piece of tubing to mark the location of the first bend. Fortunately for this one, we can simply eyeball the placement.

Make your bend as we have before — insert the tubing with the latch part way down, line up the zeros, align your mark to the L, tighten the latch, and make your bend.

With the piece back in the fitting on the body, make your second mark on the tube according to how it lines up with your scrap piece.

This bend will need to be level with the previous one. Check the level of the tool, then level the previous bend before making your second 90°.

Mark the tubing where it meets the shoulder of the fitting to make your final cut.

After deburring, insert the tube, hand-tighten the nut and then turn another 1 or 1-¼ turns with a wrench.

In natural gas production, managing your gas pressure drops is critical. If mishandled, these drops can jam up your system and cause downtime.

1. What is a Pressure Drop Across a Valve? 

A pressure drop across a valve means that the media is flowing the normal direction—from up to downstream. If you didn't have a difference in pressure between upstream and downstream—in other words, if those pressures were equal—there would be no flow across the valve.  

Production fluid, be it oil or natural gas, naturally flows from high to low pressure. That’s how the flow is determined in any kind of separation equipment or system.  

The pressure drop across a valve may also be called the "differential pressure."

How is Pressure Drop Set? 

Pressure drop across a valve is determined by the control points both upstream and downstream of the valve. If the valve is in a dump application, the pressure drop will be determined by two things:  

1. The pressure held on the separator by the back pressure regulator
2. The pressure controlled by the operating pressure of the downstream equipment

2. Does Pressure Drop Reduce Flow Rate?

Pressure drop does affect flow rate, but does not always reduce it.  

Again, every valve flowing media will have a pressure drop, which is what creates the flow. Whether the pressure drop reduces or increases flow rate depends on if the drop moves higher or lower.

Here's the general rule:  

• Higher pressure drop = more flow.  
• Lower pressure drop = less flow.

If the pressure drop gets higher (meaning there is an increase in differential pressure), there will be more flow across a valve (to a point).

If the pressure drop gets lower (meaning there is a decrease in differential pressure), there will be less flow across a valve.  

For example: A 1” trim in a 2” stem guided valve would be able to flow more with a 100 PSI drop than if it had a 50 PSI pressure drop. This is because there’s more pressure in the flow media pushing on it to force it through the 1” trim.

Note, however, that this increased flow from increased pressure cannot go on indefinitely. At a certain point, you will reach what’s called choked flow.

3. Why is Choked Flow Bad? 

There comes a point where if you’re increasing the pressure drop by lowering the downstream pressure, you’re not going to increase the flow rate. The fluid will reach its maximum velocity at the vena contracta, and after that point, it will enter a state called "choked flow."

The higher the pressure drop is, the more flow you can get across a given orifice size. If you want to increase volume using the same valve and equipment you have, but you are in choked flow, you won’t be able to.  

This creates problems in your system because you can't pass the amount of volume that you need.  And depending on the application you might be starving another piece of equipment that needs volume to operate correctly.  

4. Does Partially Closing a Valve Increase Pressure? 

If you partially close a valve, would it increase the pressure? That depends on your volume.

If you partially close a valve and you are flowing a relatively high amount of volume, upstream pressure may increase if it’s not opening far enough to release pressure.  
If the valve is partially closed and you are flowing a relatively low amount of volume, it could release enough volume so that pressure decreases.

5. Which Valve has the Highest Pressure Drop? 

There are many variables that determine what your pressure drop is, including the application and the flow conditions the valve is exposed to.  

That said, our Cage Guided High Pressure Control Valve can handle higher pressure drops than many valves because of its balanced trim.

This is because with the working pressure of the valve, there is the potential of a high pressure drop, and the valve's operation allows it to work in those high pressure drop applications.

How It Works

1. The flow through the cage-guided high pressure control valve comes from underneath the seat.
2. The upstream pressure moves through the two communication holes inside the piston. This equalizes the pressure on the top and bottom of the piston.
3. This means that the valve is balanced, so regardless of how large your pressure drop is, the valve can be opened or closed by a standard pressure of supply gas from the pilot.
    

6. What is the Solution to Choked Flow?

To get your valve out of choked flow, you must decrease the pressure differential. If you are worried about not passing enough volume through the valve in choked flow, you need to increase your valve trim size or you can increase your upstream pressure.  

One important distinction to make: Once you’re in choked flow, decreasing downstream pressure to increase the pressure differential doesn’t do anything to increase flow rate.  

If you increase upstream pressure, you’re adding more energy to push it across the valve so that can increase the flow rate because it increases the pressure drop.  

In other words, when you’re in choked flow, you can push more production fluid or gas through but you can’t pull more through.

If you add pressure from behind (upstream), you can push more through, but if you take away pressure downstream to create a higher differential, it’s not going to allow more flow through the valve.

Bonus: Cavitation, Flashing, and Staging Pressure Drops

Cavitation is the formation and collapse of air or gas bubbles in a liquid.

The bubbles are formed when liquid undergoes a rapid change of pressure and falls below the vapor pressure. These bubbles collapse when the pressure recovers.

This can all happen in a very short span just after the vena contracta—the point in the valve where the diameter of the flow is at its smallest, and fluid velocity is at its maximum.

What are the Symptoms of Cavitation? 

Because it happens inside a valve or pipeline, cavitation is not easy to spot. Here are two symptoms that may be caused by cavitation:

• Valve Trim Pitting. When the vapor bubbles collapse, it creates a strong force. When this happens over and over on the metal surface of the valve trim, the metal will begin to erode and pit.
• Water Hammering. If cavitation is occurring, your valve may repeatedly open and close sharply. This is called water hammering, and it can lead to an eventual compromise of the valve stem, coupling block and/or valve seat.

How Can I Prevent Cavitation?

There are three things you can do to prevent cavitation in your valves:

1. Decrease the pressure drop across your valve.
2. Install the valve in a cooler place in the process, thereby decreasing the vapor pressure.
3. Make sure your valve is properly sized. Cavitation often happens in applications when a valve is oversized.

Cavitation happens a lot with high pressure drops and high velocities. If you’re experiencing a high pressure drop, another problem to watch for is flashing.  

What is "Flashing" in a Control Valve?  

While cavitation is more common in liquid, flashing is more common in gas production.

Flashing happens when you reduce the pressure on a liquid hydrocarbons to the point that they "flash" into vapor.

For example: If you dump your oil emulsion quickly from a high pressure to low—say, 500 PSI down to 60 PSI—it can flash, meaning the rich, light, high-gravity oil condensate in your production vaporizes, and you lose that resource forever.

The pressure on your operation’s production vessels is what keeps this oil condensate in liquid form.

This is why producers drop gas pressure in “stages.”

What does it mean to Stage Gas Pressure Drops? 

Staging is the process of reducing pressure in stages rather than all at once. Reducing pressure all at once can not only cause freezing, but cavitation and flashing. More oil and condensate can be recovered in liquid form and not be lost to vaporization when staging pressure drops.

This is usually a concern in gas-producing wells. These operations are usually labeled as “natural gas production”—meaning gas is the largest resource the producer is recovering by volume.

However, these wells still produce oil, sometimes called “white oil” because of its light color, and it can create significant revenue for these producers.

Many producers use a gas production unit (GPU) on their natural gas wells to heat the well stream before reducing the pressure, helping to mitigate freezing. In this set up, the oil and condensates can be recovered in the separator portion of the GPU.

The dry gas, meanwhile, flows out of the top of the vessel. The gas is sent downstream into a sales line. Some of the dry gas is used to power the instrumentation on the GPU.

Staging vs. Compression

Note staging is the reverse of the process of compression. The purpose of a natural gas compressor is to re-pressurize natural gas to push it downstream.

When the gas reaches a compressor, producers want the condensate to be “knocked out” so it doesn't damage the compressor.

In many industries, engineers will create a blueprint for equipment and control layout, called a Piping and Instrumentation Diagram, or P&ID. In this video, we’ll walk through codes and symbols specifically for oil and gas production equipment so you can read and understand P&IDs in the industry.

P&ID vs PFD

Process diagrams can be broken down into two major categories:

1. Process and Instrument Diagrams (P&IDs)
2. Process Flow Diagrams (PFDs).

A P&ID is complex while a PFD is more of an overview of a process.  

A flow diagram is a simple illustration that uses process symbols to describe the primary flow path through the production equipment. It provides a quick snapshot of the operating unit and includes all primary equipment and piping symbols that can be used to trace the flow of the well stream through the equipment. Secondary flows, complex control loops and instrumentation are not included. These PFDs are more helpful for visitor information and new employee training.

Field technicians, engineers, and operators use P&IDs to better understand the process and how the instrumentation is interconnected. 

Sales personnel and OEMs (original equipment manufacturers) use P&IDs to spec equipment and build the vessels.  

Not all P&ID elements are standardized, but the instrumentation symbols follow a standard set by the International Society of Automation (ISA). The ANSI/ISA’s S5.1 standards are what this guide will be using to communicate consistently.

After some practice, you’ll become familiar with many of these codes and symbols, but if you’re just starting out or need a visual resource to reference, make sure to download our P&ID Reference Guide, which features a full list of symbols.

Download P&ID Symbols Guide

Tag Numbers

Stand alone, physical instruments are indicated by a tag number with a circle around it.

Tag numbers are a series of letters and numbers that identify a device as what it is controlling, the type of device being used, and the number assigned to it on the P&ID.

• The first letter indicates the parameters being controlled, monitored, or measured.
• The second letter tells the type of device being used.
• The third, fourth, and fifth letters further designate the function of the component and modify the meaning of the preceding letters. 

For example, “PC” is a Pressure Controller, while “PIC” is a Pressure Indicator Controller.  

This chart shows common abbreviations for what you would see and how it would be written on a P&ID. However, there are many other abbreviations that you will see such as this more comprehensive industry list.

The number below these letters is the numerator to help identify a specific component on a project within the control loop. When there are multiples of the same device used in a diagram, this number helps viewers to reference that specific instrument.  

If you were looking at a list of the controls, you could look at the control loop number to find that specific device on the P&ID.

Companies have different protocols for where these numbers originate. ANSI/ISA-S5.1 Table A.1 and A.2 dictates typical loop and instrument identification/tag numbers structure and allowable letter/number combinations for loop numbering schemes.  

A viewer can use these critical tag numbers to reference additional process information for that instrument, which helps product sizing, material selections and other variables.  

You'll notice that some components such as check valves, ball valves and isolation valves do not use tag numbers. Typically, the information given with these will be limited to their symbol and the line size.

Instrument Location

The circle combined with the presence or absence of a line determines the location of the physical device.  

No line means the instrument is installed in the field near the process.  

• Located in field
• Not panel, cabinet, or console mounted
• Visible at field location
• Normally operator accessible 

A solid line means the instrument is in a primary location in a central control room (accessible to the operator).

• Located in or on front of central or main panel or console
• Visible on front of panel or on video display
• Normally operator accessible at panel front or console 

A dashed line tells us that the instrument is in an auxiliary location in a central control room (not accessible to the operator).

• Located in rear of central or main panel
• Located in cabinet behind panel
• Not visible on front of panel or on video display
• Not normally operator accessible at panel or console 

A double solid line means that it is in a local control room or on a local control panel

Located in or on front of secondary or local panel or console 
Visible on front of panel or on video display 
Normally operator accessible at panel front or console 

A double dashed line means it’s in an auxiliary location in a local control room or local control panel.  

• Located in rear of secondary or local panel
• Located in field cabinet
• Not visible on front of panel or on video display
• Not normally operator accessible at panel or console 

These symbols may be supplemented with information on the name of the local control room or the local control panel, just outside the symbols, for example, COMPRESSOR, i.e., the local control room or local control panel for a compressor.

Shared Display & Shared Control

Shared display means you can see the same information in several locations across a network and it can be accessed anywhere. Shared control means you can change the parameters of that device remotely.  

Some instruments are part of a Distributed Control System, or DCS, where a user can select a specific controller or indicator and see it in one location, such as on a terminal screen.  

With today’s computerized systems using virtual controllers like in PLCs and DCSs, new P&ID symbols had to be developed. If you take the same tag number symbol for a physical instrument and add a square around it, it now means that it is part of a shared display and shared control in a DCS.

Line Types

Different symbols for line types tell us about the instrument. Users can identify how instruments connect to each other and what type of signal is being used.

For example, a solid line indicates piping, while a dashed line tells us that there is an electrical signal. Familiarize yourself with these different connection symbols by downloading our reference chart.

Piping Symbols

Piping symbols have various important uses you’ll want to be familiar with. For example, one important symbol to note here would be the concentric and eccentric reducers. This will help you identify when piping changes sizes. You’ll see these sometimes immediately upstream or downstream of a control device. This information is helpful for understanding flow capacity and sizing.

Control Valve Symbols

P&ID symbols can sometimes change from company to company. This is especially true with control valve symbols. This chart of common control valve symbols can be downloaded for reference but always consult the P&ID legend if available.

Pumps, Tanks and Other Types of Equipment Symbols

Here are the symbols for pumps, tanks, and other types of equipment. The most common pumps used in oil and gas industry are screw, progressive cavity, and reciprocating pumps. The most common tanks are dome roof tanks.  

If you want to learn more, please visit our website Directional Control Valve.