Pipes come in different sizes, lengths, colors, and materials; with the type of pipes being tailor-fitted for the intended application and industry. Aside from initially just sewage and water, pipes are now used to transport various substances with varying hazard levels, ranging from non-toxic to toxic. Piping systems in facilities may contain 2 or more kinds of substances, and as such raised the need for proper identification and labeling systems (pipe marking) in order to track the contents of each pipe, flow direction, and of course, to promote safety and avoid accidents.

In the early days, pipes were predominantly used for sewage and irrigation systems. The first pipes were mainly made out of terracotta clay, wood, cast iron, and even lead. Nowadays, pipes are made out of a variety of sturdier and more refined materials such as forged steel, brass, copper, and polyvinyl chloride (PVC). The ingenious design of the pipe allowed contents to be transported from one place to another, enclosed. As time progressed, so has the usage of pipes. They can be seen almost everywhere; be it in electric power plants, sanitation, manufacturing, industrial, or even telecommunication.

Piping networks can be very intimidating and confusing due to the numerous pipes overlapping and going in different directions. But it doesn’t have to be. Rule 1230: Identification of a Piping System (Occupational Safety and Health Standards) as well as Piping of the Philippine Mechanical Code are helpful standards that can be used as guides which places emphasis on the visibility and ease of identification of labels, in order to implement an effective pipe marking system (note: the standards mentioned are applicable for exposed pipes and does not cover pipe systems buried in the ground).

With that, here are the things to consider for pipe markings:

1. Color coding

- used to easily identify the contents. Colors are designated for a specific type of use. It can be applied to the whole pipe, or on the labels to be used.

2. Bold text and symbols

- these can be stencils or printed on labels, naming the contents of the pipe, as well as other essential information (e.g., toxicity, temperature). The color of the text should also be in contrast to the background for better visibility.

• Red Marker/White Text

• Orange Marker/Black Text

• Yellow Marker/Black Text

• Brown Marker/White Text

• Green Marker/Black Text

• Blue Marker/White Text

• Purple Marker/White Text

• Black Marker/White Text

• White Marker/Black Text

• Gray Marker/Black Text

3. Arrows

- to indicate the flow direction of the pipe contents.

4. Label/Text size

- should be visible and readable. This would take into consideration the size/dimensions of the pipe.

5. Label position/placement

- should be easily visible for personnel (e.g., eyelevel). It should be placed on necessary areas in the pipe systems. This includes access and end points, junctions, near valves and flanges, points where there is change in flow direction, as well as along the length of long pipes at intervals (every 25 to 50 feet spacing on straight runs). For instances where there are obstructions (such as when pipes penetrate floors or walls), the labels must be placed in such a way that the labels are still visible when viewed from both sides and different angles.

The surfaces where the markers will be placed should be free from any substances that may prevent it from adhering properly. It is also important to ensure that the markers used will stand the test of time when it comes to actual use; it must be made of materials that are durable enough to withstand weathering and deformation, may it be temperature change, exposure to light and substances (e.g., grease, acids), or the regular cleaning and maintenance.

Given that the above specifications have been met, does not however guarantee 100% safety or success, due to human error. On an evening back in April 2014, sixteen workers in Batangas were doused with caustic soda (chemical name: Sodium hydroxide, commonly known as liquid sosa) while cleaning inside the pipes. These pipes were large enough to fit people inside. During cleaning, one of the employees in charge of the valves that control the flow of chemicals have mistakenly opened the sprinkler system for caustic soda, thus resulting to the accident. They were rushed to the hospital afterwards, 7 of which remained in confinement due to eye injury.

As with any standard or system, proper training and orientation of all personnel should be conducted in order to help avoid human error. All workers should be able to understand the importance of the pipe marking system, be able to identify the labels, and know the repercussions of not conforming to the safety standards. Exercises to help them become aware and be kept involved in the proper implementation of standards can be employed. Routine checks of the facility and internal audits coupled with proper documentation can also be done to ensure full implementation, and of course, help in maintaining an accident-free workplace.