Proper Valve Identification and Labeling Standards and Tips

Improving a facility’s safety and efficiency often is as simple as using proper valve labeling and identification practices. Even though valves may not be a main component of heavy machinery, they can do quite a bit of damage if someone opens the wrong valve. The other benefit of using the appropriate valve labeling and identification practices are significant reductions in the risk of spills, accidents, and injuries caused by the valves and pipes in a facility.

If you want to improve the safety of your facility by adding valve labels for the first time, or if you are looking to improve your valve labeling and identification processes, there are a few standards and practices you should follow including

Read on to learn more about the proper valve labeling and identification processes, standards, and practices.

1. Determine Which Parts of the Valve Need to be Labeled

Valve labeling and identification can be quite an undertaking because there may be hundreds of control valves and thousands of manual valves within a facility or refinery. The challenge is to properly label and identify growing numbers of valves that require repair, maintenance, and validation. Not only do facilities and refineries have several types of valves such as solenoid, gate, plug, butterfly, pinch, diaphragm, ball, and globe, but they also have valves that require identification on several different parts including the body of the valve, bottom of the valve, and underside of the valve.

When determining which parts of the valve need to be labeled, keep in mind that the objective of the tags and labels is to ensure safe operation. All tags and labels should be placed in locations that are visible to everyone. As such, you should not place tags or labels on valve handles or wheels. The Department of Energy clearly states that labels for valve components “should be permanently attached to the components (e.g., attached to the valve yoke, not to a removable part such as a handwheel) in a way that will not interfere with the normal operational use or testing of the component. Valves operated by reach rods or chains, or other remotely operated components, should have an additional label installed at the operating device. Labels for chain operators should be attached to a small piece of tubing through which the chain passes, so the label always remains at the bottom of the chain loop. If the valve is difficult to be seen from the operating location, the label should indicate the open and close direction for the chain or other operator.”

Image via Pixabay by Tama66

2. Know and Understand Valve Labeling Standards

Unfortunately, the American Society of Mechanical Engineers (ASME) and the American National Standards Institute (ANSI) do not explicitly require valve tag placement. However, they do have codes requiring proper marking of piping systems, and those codes typically apply to valves because valves are part of piping systems. As such, valve tags use the ANSI/ASME A13.1 standard for color coding (a pipe labeling standard followed in the industry for valve labeling purposes due to the lack of a separate standard for valve labeling). The tags must identify the valve and usually do so by including the valve number. The tag also typically identifies the valve type and system of which the valve is a part. It’s important to note that the type of valve specified is dependent upon its function rather than on the design of the valve. Additionally, valves such as ball and gate valves are described according to their design and usually are not specified on the valve tags.

The ANSI/ASME A13.1 color code includes six standard colors and four user-defined colors. The six predefined colors identify types of pipe contents, and the standards provide definitions to help facilities use the correct colors. The user-defined colors, on the other hand, are defined by individual facilities using the standard, and the facilities must document the definitions and train workers. The color code is as follows

• Fire-quenching fluids: White text on red background
• Toxic or corrosive fluids: Black text on orange background
• Flammable or oxidizing fluids: Black text on yellow background
• Combustible fluids: White text on brown background
• Other water: White text on green background
• Compressed air or other gases: White text on blue background
• User-defined: White text on purple background
• User-defined: Black text on white background
• User-defined: White text on gray background
• User-defined: White text on black background

There are some points of confusion that arise from the ANSI/ASME A13.1 color code. First, facilities question the difference between flammable and combustible. According to the standard, if the material is a vapor or produces a vapor that could ignite and burn in air, it is flammable. Other materials that could pose a fire hazard fall into the combustible category.

Sometimes facilities question how to label pipes and vales that fall into multiple categories, as is the case then flammable gases also are toxic. Generally, each facility makes the decision. Some facilities identify the hazard type that is more significant to them specifically and use the color for that particular hazard; other facilities use a user-defined color to identify combinations of hazards.

Image via Pixabay by Amigos3D

3. Utilize Proper Tag Placement

Label and tag placement on pipes and valves is critical to facility safety. Facilities typically follow four general rules about placing pipe labels and valve tags; these rules follow recommendations from ANSI.

1. Place pipe labels at all directional changes
2. Place pipe labels on both sides of the entry points through floors and walls
3. Place valve tags next to all valves and flanges
4. Place pipe labels at 25-50 foot intervals on straight runs

It is best to place valve tags in locations where workers will clearly see the pipe contents and valve information prior to opening the valve itself. It is important never to attach valves to valve stems or actuators. In many cases, tags are attached to valves using plastic or metal ties.

4. Use the Proper Type of Valve Tag

Valve tags can be made of a variety of materials including plastic, metal, wood, or paper. Metal valve tags are popular because of their durability. They are available in a variety of metal types including stainless steel, aluminum, and brass. Stainless steel tags are ideal for environments that include water and chemicals because they resist rusting and corroding. Aluminum tags are light weight and capable of being engraved. They are a good choice for environments that have low temperatures; however, they are not as strong in extremely hot environments. Brass tags are strong and may be used in high-temperature situations and environments that are corrosive.

Tags also vary in size from small circles to large squares, depending on the amount of information they need to contain. Of course, facilities need to select the proper type of tag for the valve environment in which it will be placed. Thus, safety managers often use multiple types of tags throughout their facilities. They also often choose tags that follow the pipe color schemes to have a consistent labeling system that visually communicates information to workers.

There are many considerations to make when labeling and identifying valves and pipes in a facility. Safety manager should determine which parts of the valve need to be labeled, know and understand valve labeling standards including ANSI/ASME A13.1, utilize proper valve tag placement, and use the proper type of valve tags throughout their facility.

Image via Flickr by PEO, Assembled Chemical Weapons Alternatives

Safety valves and pressure relief valves are crucial for one main reason: safety. This means safety for the plant and equipment as well as safety for plant personnel and the surrounding environment.

Safety valves and pressure relief valves protect vessels, piping systems, and equipment from overpressure, which, if unchecked, can not only damage a system but potentially cause an explosion. Because these valves play such an important role, it’s essential that the right valve is used every time.

Here are six factors that must be considered when selecting and sizing safety or pressure relief valves.
 

1. CONNECTION SIZE AND TYPE
   The valve size must correspond to the size of the inlet and discharge piping. The National Board specifies that the both the inlet piping and the discharge piping connected to the valve must be at least as large as the inlet/discharge opening on the valve itself.
   The connection types are also important. For example, is the connection male or female? Flanged? All of these factors help determine which valve to use.

2. SET PRESSURE (PSIG)
The set pressure, which is measured in pounds per square inch (PSIG), is the pressure at which a safety or pressure relief valve opens.

The set pressure of the valve must not exceed the maximum allowable working pressure (MAWP) of the boiler or other vessel. What this means is that the valve must open at or below the MAWP of the equipment. In turn, the MAWP of the equipment should be at least 10% greater than the highest expected operating pressure under normal circumstances.

3. TEMPERATURE
Temperature affects the volume and viscosity of the gas or liquid flowing through the system. Temperature also helps determine the ideal material of construction for the valve. For example, steel valves can handle higher operating temperatures than valves made of either bronze or iron. Both the operating and the relieving temperature must be taken into account.

4. BACK PRESSURE
Back pressure, which may be constant or variable, is pressure on the outlet side of the pressure relief valve as a result of the pressure in the discharge system. It can affect the set pressure of the upstream valve and cause it to pop open repeatedly, which can damage the valve.

For installations with variable back pressure, valves should be selected so that the back pressure doesn’t exceed 10% of the valve set pressure. For installations with high levels of constant back pressure, a bellows-sealed valve or pilot-operated valve may be required.                                                                                                                                                                                           

5. SERVICE
Different types of service (steam, air, gas, etc.) require different valves. In addition, the valve material of construction needs to be appropriate for the service. For example, valves made of stainless steel are preferable for corrosive media.

6. REQUIRED CAPACITY
Safety valves and relief valves must be able to relieve pressure at a certain capacity. The required capacity is determined by several factors including the geometry of the valve, the temperature of the media, and the relief discharge area.

The required capacity is set by the applicable code. It is usually expressed in:

• LBS/HR – pounds per hour (steam flow),
• SCFM – standard cubic feet per minute (air or gas flow), or
• GPM – gallons per minute (liquid flow).

These are just the basic factors that must be considered when selecting and sizing safety valves and relief valves. You must also consider the physical dimensions of the equipment and the plant, as well as other factors related to the environment in which the valve will operate.

Let us put our valve expertise to work for you. Contact us for help selecting the right valve for your project.