Your Guide to Proper Pipe Marking

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Proper Pipe Marking

When looking to implement or update a pipe marking system, it’s important to start with gathering as much information as possible. While the concept of pipe marking looks to be straight forward, there is actually a lot to learn in order to successfully become compliant with pipe marking standards. It is common knowledge that visual communication plays a crucial part in employee safety, which is why a variety of pipe marking standards exist in the industrial world. In fact, marking visible pipes helps foster a heightened sense of awareness in employees when they are around potentially hazardous chemicals.

With that in mind, this guide has been put together to help provide a one stop source for everything about pipe marking and how to go about it. It will include different standards that exist, how to choose the right pipe marking material, using valve tags, and much more.

By beginning a pipe marking journey with this guide, employers are ensuring their facility's pipe markings are safe, easy to understand, and helpful for all employees.

ANSI/ASME Pipe Marking Standards

The American Society of Mechanical Engineers, also known as ASME, has created a variety of requirements when it comes to labeling pipes. Accredited by ANSI, the American National Standards Institute, they both work together to provide consistent pipe labeling protocol for any industry that needs it. Whenever discussing pipe markings, the voluntary ASME standards must be followed because of their proven excellence in providing a safer environment for employees. Learning about these standards will help ensure company compliance with OSHA regulations as well.

One of the best ways to learn about ASME standards is by looking at the ANSI/ASME A13.1 standard. This document will help with identifying information needed on a given pipe marking label, whether that be relating to colors, size of the label, symbols, or verbiage.

Updated in September of 2020, ANSI/ASME A13.1 has reiterated that ANSI/NEMA Z535.1, American National Standard for Safety Colors, as well as the Globally Harmonized System of Classification and Labeling of Chemicals, also known as GHS, play a part in the ANSI/ASME A13.1 standard. All three work together to provide the best advice on how to proceed with pipe marking in any facility.

ASME Pipe Color Code

Standard Pipe Color Code from ANSI/ASME A13.1

The ANSI/ASME A13.1 standard for pipe colors is often used as a starting point for many facilities that are looking to improve their visual communication program. A standard set of colors paired with text and an occasional symbol helps to identify the substance in a pipe quickly and in a concise manner. Standardized colors and symbols help to eliminate excessive verbiage and prevent confusion when attempting to identify hazardous materials.  

The colors that the A13.1 standard requires are as follows:

  • Flammable and/or oxidizing - Any pipe that contains flammable fluids or vapor, or any kind of oxidizing agent, needs to have a label with black text on a yellow background.
  • Combustible - Fluids that can ignite in the presence of a heat source, but are not flammable under normal circumstances, should be written with white text on a brown background.
  • Toxic and/or Corrosive – Pipes containing fluids that can be toxic or corrosive should use black text with an orange background.
  • Fire Quenching - Water or other fire suppression substances need to be labeled with white text on a red background.
  • Other Water - Any water that is not intended to be used for fire suppression should be labeled with white text on a green background.
  • Compressed Air - Any vapor or gas that is under pressure but does not fit in another category (such as compressed air) will be labeled with white text on a blue background.

There are also several options for user defined color codes. These include white on black, black on white, white on purple and white on gray. Whenever using these 'open' color options, make sure that they are followed throughout the facility to avoid any confusion.

The Option to Incorporate GHS Pictograms to Pipe Markings

There is even the option to include GHS pictograms on pipe marking labels to provide continuity and a maximum level of communication between workers and their environment. This happens usually in the event there is a larger container that has a standard GHS label and it is connected to a pipe. If this route is chosen, the label must follow the A13.1 standard color scheme, as well as include the following information:

  • The product identifier
  • The pictogram(s)
  • The signal word
  • The physical, health, and environment hazard statement

The more information, the better when it comes to dangerous chemicals.

ANSI Pipe Label Size Standards

Determining the Size of Pipe Labels

The size of a pipe label and the corresponding text size depends on the diameter of a pipe. The smaller the pipe the smaller the label, and likewise for pipes increasing in size. The goal of standardizing sizes for pipe labels is to maximize visibility for employees when passing by or when performing maintenance on a set of pipes. ANSI and ASME’s A13.1 standard describes the needed sizes of pipe labels ranging from pipe diameters of ¾ of an inch to 10 or more inches. The standard also states that pipes of less than ¾ of an inch require a permanent and legible tag.

Unique Pipe Marking Color Standards

When deciding what type of color standards to use for labeling a facility, it is important to know all the possible options. There are pipe marking standards for marine vessels, medical purposes, and wastewater treatment, to name a few. Unique environments may call for different color recommendations or even combinations of colors to keep employees safe and aware of their surroundings. The decision to use voluntary standards put forth by standard setting organizations like ANSI, ASME, or the NFPA, is always a prudent one, as the standards might still be mandatory by OSHA.

Carefully choosing which color standards to use is well worth the effort, as it will not be an easy feat to change later down the road. High quality pipe marking labels can last for years and if the standard within the facility is changed, replacement of all outdated pipe markings will be necessary.

Marine Pipe Marking

Sea Vessel and Marine Pipe Marking: ISO 14726:2008

As mentioned above, one of those unique pipe marking situations revolves around marine vessels. These pipe color codes can often be quite different from those that are used on land due to the use of different chemicals, and other potentially dangerous environmental hazards for those in the vessel and the aquatic life surrounding it. For those reasons, keeping in line with marine pipe color standards is important for anyone that operates these types of vessels or facilities.

ISO 14726:2008 is the standard that corresponds with marine pipe labeling. Put forth by the International Organization for Standardization as a Draft International Standard, this document describes the process of identifying the contents of piping systems on ships and marine technology by using colors. Not only will following this standard help to ensure consistency across all marine vessels, it will also help vessels stay compliant globally.

Documenting Facility Specific Pipe Marking Standards

Once a pipe marking standard has been implemented and established within a facility, it is highly recommended that the employer create a document with all the pertinent pipe marking information for their employees. This book, chart, PDF, or physical sign should clearly communicate the color meanings, any abbreviations or number sequences, what they are used for, and when they should be used. A set pipe marking code will allow a facility, and all its departments, to have everything they need to make the environment as safe as possible.

Knowing that facilities globally will use varying pipe marking standards, the collective use of a pipe marking key or chart for the benefit of the employees, will improve the same core areas of safety. To elaborate, a displayed pipe marking code may help with the following:

  • Training: When new employees are brought on board, they will have immediate access to all the necessary pipe marking information. This will keep them safe as well as those around the new employees.
  • Remembering and reminders: Employers cannot expect every employee to be a star pupil in remembering every single detail about pipe identifiers. Having a key or pipe marking book around will aid their memory. Eventually, those details will be engrained in their brain making the key a gentle reminder in case they forget.
  • Safety: Guessing is the exact wrong way to go about identifying pipe contents. Having a facility specific pipe marking code will immensely aid in keeping employees from making assumptions about hazardous materials.
  • Standardization: Different departments should not be going by separate pipe marking codes. This can generate confusion between departments and can result in accidents. Standardization, just like beginning a pipe marking program, must follow through and be identical in all departments for safety and clarity.

The Importance of Training Employees on Pipe Marking

Whenever working with piping in any facility, it is important to remember that the number one goal is ensuring everyone has the ability to work in a safe environment. This not only requires high quality pipe labeling materials, but also clear communication of information regarding the meanings of those labels.

As with any safety improvement strategy in a facility, it is critical to incorporate training into the overall plan. Sharing pipe marking information with employees who will be in direct contact with those pipes during everyday tasks will help with getting the most out of any pipe marking plan.

Without proper training, wasted time and a lack of safety will plague the facility because employees will need to stop to read each label and consult the provided color chart if they are responsible, and haven’t made any assumptions about the pipe’s contents. A lack in knowledge can lead to delayed responses in emergency situations.

Appropriate times for training employees on identifying pipe contents by labeling include:

  • Onboarding - Whenever a new employee is hired to work with various pipe related tasks, they need to be trained in areas such as color charts, hazardous materials, and on emergency situations.
  • Refresher - Refresher training for employees annually is a great way to keep them up to date on identifying the contents of pipes.
  • Visual Reminders - Signs, posters, and other visual reminders placed around a facility is a great way to reinforce what people already know. Whether it’s just covering the color guide or reinforcing more detailed information, these visual reminders are very effective.
Pipe Marking Arrows

The Types of Pipe Labels Available

There are numerous ways to label pipes and valves in a facility that are OSHA compliant, follow ANSI standards, and give an extra boost to safety protocol for employees. The two categories to choose from include vinyl tape material and valve tags. However, there are several different choices to pick from within those two categories of which we will go into depth here.

Pipe Marking Vinyl

Pipe marking tape, or vinyl, is the most popular way to identify the contents of pipes. It is easy to apply and lasts years without fading, smudging, or tearing. For that reason, it is one of the most cost-effective options and is easy to comply with OSHA regulations and pipe marking standards. There are countless types of vinyl to choose from, some of the most common types of vinyl used for pipe marking include:

There are also options for arrow tape to be used alongside normal pipe marking activities to identify the direction in which the contents are flowing.

Pipe Marking Valve Tags

Valve Tags

The best way to mark a pipe valve is to use a valve tag. These tags can be placed directly on the valve and will help to inform employees about its contents, the potential dangers that chemical poses, and more.

Valve tags are extremely easy to use and very effective. Facilities should ideally have them placed on every valve that is used. This includes water valves, chemical valves, gas valves and any others that are present. Taking just moments to attach, the tag can remain in place for years without a problem. There are many types of valve tags to choose from depending on the specific situation. Those options include:

  • Stainless steel valve tags which are durable and can even withstand chemical exposure. AutoCAD programs allow for detailed engravings of important information as well.
  • Plastic valve tags are reusable due to companies printing off vinyl stickers of needed information and applying it to the tag.

Choosing the Right Pipe Marking Supplier

Picking a reliable and high-quality pipe marking supplier will make a pipe marking project much more manageable. A good supplier will ensure that their customer has access to the most common types of pipe marking labels and other tools that are also compliant with standards and regulations.

Piping often extends great distances throughout a facility which means many labels will be needed to outfit it properly. There are often options for pre-made labels as well as the option to make them in-house without having to wait on lead times or worrying about mistakes.

The following are a few different types of labels that can be beneficial to any facility:

  • Ammonia Markers - If the facility uses an ammonia refrigeration system it is essential to use approved ammonia markers. These markers need to meet the IIAR standards for abbreviation, physical state, marker body, pressure level, and flow direction.
  • Pre-Made Pipe Marking Labels - Standard pipe marking labels are availablefrom any good supplier. These will be common labels such as ones that say, "Fire Sprinkler" or “Hot Water.” Others can be custom printed by the supplier to meet specific needs.
  • Pipe Marking Arrow Tape - Identifying the directional flow of the pipe’s contents is absolutely necessary. The easiest and most effective way to do this is by using arrow tape. As the name implies it is just tape with arrows pointing in one direction.
Pipe Marking Printer

Creating Pipe Labels with an In-House Printer

Another great option is to obtain a label printer for the facility. The ability to print labels in-house ensures quick and easy access to labels when needed. They can print exactly what is required at the fraction of the cost of labels made and shipped by a supplier. For that reason, many companies choose this option, it saves on time and cost.

There are a variety of excellent pipe label printers on the market to choose from. Pipe labeling is not their only specialty, they can be used for making any types of labels or signs that a business needs to keep its employees safe. Check out the following three popular industrial label printers:

  • LabelTac 4 - The LabelTac 4 is great for printing between ½" and 4" labels. It can create easy to read visual reminders for employees. This printer also comes with a lifetime warranty.
  • LabelTac 4 PRO - The Pro version of the LabelTac 4 printer has an upgraded cutter, motor, and print head to ensure a faster and easier printing process. It also has an upgraded ribbon capacity allowing for longer times between changing out the ribbon supply.
  • LabelTac 9 - This is the largest industrial label printer commonly used. It is for labels between 4'' and 9'' in width. It is made with die-cast metal and has a clear media view for easy use.


There is a lot to learn when it comes to pipe marking, but the more time that is spent learning about how to properly mark pipes, the better off a facility will be. When pipe marking is taken seriously, employees will catch on and continue to practice safe behavior. Taking the time to label pipes and valves correctly is well worth the effort regarding the improvement in safety.

Consider taking a few minutes to watch this simple video about pipe marking and how it should be done:

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