A boilermaker is a trained craftsman who produces steel fabrications from plates and sections. The name originated from craftsmen who would fabricate boilers, but they may work on projects as diverse as bridges to blast furnaces to the construction of mining equipment.


Many boilermakers are employed in repairing, repiping, and retubing commercial steam and hot water boilers used for heating and domestic hot water in commercial buildings and multi-family dwellings. Sometimes these boilers are referred to as pressure vessels. Generally, a pressure vessel is a storage tank or vessel that has been designed to operate at pressures above 15 p.s.i.g. The main two tasks of boilermakers involve; using oxy-acetylene gas sets to cut or gouge steel plate and Gas Metal Arc Welding (GMAW), also know as Metal Inert Gas (MIG) welding.

R Stamp Welding

Boiler repair in the United States is governed by the National Board of Boiler and Pressure Vessel Inspectors and the ASME under a classification called R Stamp Welding. In order to perform R Stamp welds and repairs, boilermakers are tested and certified in the quality of their weld joints through a rigorous tesing procedure. The name of the certificate comes from the fact that certified welders are issued a steel stamp that they actually hammer into their work, a logo consisting of the letter R surrounded by a cloverleaf design.

Power Piping

Welding, fitting, and installing the tubes and accessories that attach to the boiler can also be performed by boilermakers, And is governed by the same organizations as R Stamp Welding, except this certification is called Powerpiping certification. The Powerpiping stamp is contains two "P"s the first inverted so that it mirrors the second.


Boilermaking, welding, and fitting pipe can be a full-time year round project at powerplants- since stress fractures, leaks, and rust and corrosion cause a continual need for repair or replacement, and power plants often operate at very high steam pressures. Other boilermakers might work seasonally or on an individual project such as re-fitting a boiler in a seagoing vessel, or in the one-time remodeling of a steam plant.

Boiler repair can be a very valuable service since even the smallest steam boilers for dry cleaners, tailor and alterations shops cans cost upwards of ten to twenty thousand dollars (US) to replace.

Trade unions

The International Brotherhood of Boilermakers, Iron Ship Builders, Blacksmiths, Forgers and Helpers is a labor union which represents boilermakers and workers in related trades in the United States and Canada.

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