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Pipefitting is the science and skill of fabricating structures and conduits out of all types of piping, usually for the purpose of handling liquids or gases. Pipefitters are included within the same job description as Plumbers and Steamfitters by the Bureau of Labor Statistics. And while they all share some common skills and practices in their job specifications, there are significant differences in the skillsets. Let’s start with a general definition of plumbing vs pipefitting, and how they differ.

Pipefitter vs. Plumber – What’s The Difference?

Plumbers primarily focus on the installation, maintenance, and repair of systems that carry and supply potable water, as well as the removal (drainage) of wastewater like sewage and runoff. This includes tasks such as installing and repairing water supply lines, toilets, sinks and shower systems, and waste disposal systems. Their work primarily focuses on residential properties, office buildings, apartment buildings and hospitals. Plumbers working on residential properties usually work with . Piping that is joined together is usually brazed instead of welded, or their joints screw together and are tightened to a specific torque.

Pipefitters usually work with piping that transport gases and industrial liquids. Depending on the project, they might complete the installation or assembly of large-diameter high-pressure piping, fabricate custom piping systems to a design specification, or maintain and repair existing high-pressure piping systems. They most likely work in large industrial settings such as conventional and nuclear power plants, petrochemical facilities, and refineries. They also may work in shipyards and on agricultural and infrastructure projects.

Pipefitters might also work with the installation, maintenance and repair of oil or gas-fired boilers in both high- and low-pressure systems. Pipefitters sometimes work with aluminum and copper tubing for refrigeration and cooling systems. This can be something as straightforward as the refrigeration system on a walk-in refrigerator at a convenience store, to a massive and complex cooling system for a large apartment building, factory, or hotel.

The work of a pipefitter is strictly governed by . The piping used in these industrial scenarios often have much larger dimensions than those found in residential plumbing and are made to transport potentially hazardous materials at much higher pressures than household plumbing. Pipefitters normally do not do residential or commercial plumbing.

A Pipefitter’s Job Duties as Per the ASME

In the course of normal job duties, a pipefitter often prepares, cuts, and welds (or brazes) piping together to connect infrastructure or system components. The American Society of Mechanical Engineers (ASME) governs the rules and regulations for pipefitting in the United States. As the ASME B31 standards indicates, pipefitters work within a huge array of sub-codes and specialties, as indicated by this sampling of codes. It is a major benefit for pipefitters to develop specialty skills in more than one of these areas:

ASME B31 Standardized Code Examples¹

• B31.1 - Power Piping is intended for piping associated with power plants and district heating systems. It also covers geothermal heating systems.
• B31.3 - Process Piping (once called the Chemical Plant and Petroleum Refinery Piping Code).
• B31.4 - Liquid Transportation Systems for Hydrocarbons, Liquid Petroleum Gas, Anhydrous Ammonia and Alcohols holds the record for the B31 Code with the longest title. Basically, it is a buried pipeline transportation code for liquid products.
• B31.5 - Refrigeration Piping.
• B31.8 - Gas Transmission and Distribution Piping Systems address the transportation of gases and it too is largely a buried piping code.
• B31.9 - Building Services Piping.

Pipefitting Is Needed in All Four Sectors of the Economy

A pipefitter’s talents are needed in all four primary sectors of the economy². These are the four sectors of the economy with examples of how Pipefitters are needed in each one.

• Primary Sector – This sector deals entirely with raw materials, such as mining, drilling for petroleum and large-scale agriculture. In all cases, complex piping would be needed to handle both water supply and drainage capabilities, as well as extraction of raw goods. For large farms, oil rigs, and deep mines, this type of piping would need to be of a very large scale and be built to standards that allow it to last under heavy loads, extreme temperatures, and weather conditions.
• Secondary or Manufacturing Sector – The manufacturing of any complex product that requires piping would be included in this category; think vehicle manufacturing, major utilities and waste-water plants, and the assembling of fire suppression systems in large buildings. In the transportation sector, pipefitters are also needed by vehicle repair shops and fleets, as they will be needed to skillfully maintain and repair hydraulic or pneumatic lines on heavy equipment, buses, trucks, in shipyards and aircraft. Transportation also encompasses the roads and bridges we drive over. Any piping that is placed under the road as a conduit for power, or storm water control requires a pipefitter. This list in only a sampling of the many manufactured items that require a pipefitter.
• Tertiary sector – Any service-related business, such as hospitality, healthcare, IT, or retail, requires some degree of fitment for piping, depending upon the equipment they use. Think along the lines of water filtration and temperature control equipment for hotel pools, and large-scale water use at theme parks and large resorts.
• Quaternary Sector - which includes education, research and development and public projects. For education, an experienced pipefitter would be needed to teach the next generation of students entering the pipefitting industry. In research and development, test equipment and experimental systems might require a pipefitter to construct both supply lines for coolant and fuels, as well as waste capture.

Pipefitters Often Employ Welding

The Pipefitter must have strong skills in many types of welding, as well as a mechanical aptitude. The welding techniques used can vary greatly, and that depends on the materials being joined together, the end-use of the product, and the environment it will operate in. Welding types usually include Gas Metal Arc Welding (GMAW/MIG), Gas Tungsten Arc Welding (GTAW/TIG), Shielded Metal Arc Welding (SMAW), and Flux Cored Arc Welding (FCAW), which we cover in detail in our article regarding the four most popular types of welding processes.

The Pipefitter Is an In-Demand Essential Skilled Career

The national demand for pipefitters is more than 42,000 jobs per year until at least 2032³. With this demand level, a career as a pipefitter is an attractive proposition. Pipefitting cannot be offshored and is absolutely crucial to a functioning modern economy. Learn how to become a pipefitter.

¹ ASME B31 Code Chart retrieved from on June 4, 2024.

² Sectors of the Economy, published on 19 December 2021 at , and retrieved on April 18, 2024.

³ National Center for O*NET Development. National Employment Trends: 47-2152.00 - Plumbers, Pipefitters, and Steamfitters. O*NET OnLine. Retrieved April 18, 2024, from