Pipe Marking For Safety Managers: Start to Finish

In many modern day factories and other facilities, materials flow through lengths of piping that run throughout. These materials can often be hazardous and subject to other dangerous conditions (such as heat and pressure) and are thereby potential safety hazards to workers in their vicinity. To address this, you should learn to effectively evaluate and label any exposed (above ground) piping flowing through your workplace. In this blog post, we’re going to go over your obligations when it comes to pipe marking, as well as some industry standards and best-practice methods for doing so.

Pipe Marking and Your Obligation

Your obligation to label exposed piping is a sort of gray area, seeing as the official ANSI (American National Standards Institute) markings for pipes have not been adopted in most official capacities by the OSHA. However, OSHA regulations do require you to label and take reasonable preventative action with regards to any known possible workplace hazard under the General Duty clause. You can still be penalized by the OSHA for this reason if you have not properly labeled a pipeline (namely those carrying extremely hot/extremely cold, pressurized, or toxic materials). Though the OSHA does not dictate specifications for pipe labeling, the ANSI labeling standards for such pipelines are an industry accepted consensus, and are nearly universally followed.

The 3 Pipe Marking Categories

Before marking, you should be aware that there are three distinct categories as outlined by the ANSI for pipe classifications, and they’re based on what will be running through them.

The first category is highly hazardous material. The following fall under this category:  Anything that is corrosive or caustic, substances that are toxic or that would create toxic gases when exposed to outside air, anything explosive or flammable, radioactive, or any substance that could harm an employee if the pipe leaked or burst (including extreme temperatures or pressure).

The second category is low hazard materials. Low hazard materials aren’t particularly dangerous and only have a small chance of harming employees through mild temperatures and pressures.

The third category is reserved for fire suppression materials, such as water and anti-fire foams.

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Labeling Each Category

If you were only labeling one category, obviously the highly hazardous materials pose the most threat to your employees and expose you to the most liability – make sure these are marked every time. However, the ANSI has outlines for marking pipes carrying the other two categories as well, and it’s recommended that you mark all pipes regardless of what they carry (if nothing else this helps differentiate between more and less dangerous materials). Here are the accepted labeling styles for each category of pipe.

All high hazard materials should have a label that has a yellow background and a black typeface.

There are two sub-styles for marking low hazard class materials:  Liquids use white characters with green as a background, while a blue background with white characters are used for gases.

White letters on a red background are used for anything in the fire suppression class.

It is also worth noting that color codes have been updated in recent years to better narrow down categories of materials, refer to the ANSI/ASME 2007 changes for the new and greater range of labeling schemes.

Sizing:  Labels should be a minimum ½ inch tall, but should increase with the proportion of the pipe diameter. For example, any pipe with a diameter over 10 inches should have a label 3.5 to 4 inches high.

Direction:  Your labels should indicate in some way which direction liquids or gases are flowing through the pipe. This is most easily indicated by an arrow, which can be double-ended in the cases of a pipe that can be flowing either direction.

Placement:  Label placement is a big part of making sure that your markings are effective. Think about the height of your average worker and the height of the pipe that you’re labeling; if the pipe is on the ground, label the top of it, if it’s on the ceiling, label the bottom, if it’s at eye level, label the side (or both sides of the pipe can be seen from multiple angles). In any event, you want the labels to be easily spotted from a typical vantage point – this is usually that of a standing worker, but it could be from the perspective of someone sitting down depending on the work being done in the area (think about this when placing your own labels).

You’ll also want to mark various connection points, valves, and anywhere where flow can change direction with a label (as well as every 50 feet of straight pipe length). These are the points that are most likely to be accessed by workers and so you want to make sure labels are easy to spot at any such junction. 

When it comes down to it, you’re left with some freedom in your labeling process depending on the industry you’re in. While some industries are required by the OSHA to follow certain ANSI pipe marking guidelines (see 29 CFR 1910.6), others are not, and you’re again left in a gray area. You can follow the accepted industry norms or you can come up with your own system if you fall into this gray area. There is an implied third option in those industries which are not required to label by OSHA, which is to just not label your above ground pipes at all – don’t pick this option. You might get away with it, but you might also get slapped with a fine due to the General Duty clause and it’s also more dangerous for your employees.

If you choose to implement your own system, all that really matters is that it does the following two things:

First, it has to be universal and consistent across all of your pipes. You need to keep a written document explaining the labeling system you’re using and laying out a set of guidelines for labeling new pipes with various materials. This written rulebook should be available to show any inquiring OSHA inspector. 

Second, you need to explicitly train your employees on your system so that your labels are easily recognizable to them. As long as an employee can figure out at a glance what is being said about a pipe line (including material, direction, and any additional warnings for temperature or pressure), then you’ve got your bases covered. Training employees is especially important when you use a unique or customized version of the marking system because workers hired from other jobs may be used to a different system (often the exact ANSI one), and therefore might mistake or not be able to understand your labels without explicit instruction as to what they mean. When OSHA does an inspection, they often interview and observe employees to determine if they are aware of your safety rules and procedures, which is just as important, if not more, as having them in place.

Well there you have it, the A to Z of marking pipes. As with all safety related measures that you might not yet have implemented, the front end costs are often fairly insignificant. Even if they do start to add up, they still will pale in comparison to long term costs such as violation fines, and especially the cost of an at-fault injury on the job as a result of cutting corners.

Make sure to check out Creative Safety Supply’s LabelTac 4 Industrial Label Printers to help with all your pipe marking needs.


Tony, Good Information!

Pipe Marking is essential to an organization’s visual workplace. Properly marked pipes take the guessing game away, while keeping employees and visitors informed. Consistency is key though, as you mentioned. A visual workplace is supposed to improve efficiency and productivity. If you lack consistency throughout your pipe marking efforts, your efforts will simply go to waste.

Kyle Holland, fellow blogger at Creative Safety Supply