Uniform Mechanical Code

Designated as an American National Standard, the Uniform Mechanical Code (UMC) is a model code developed by the International Association of Plumbing and Mechanical Officials (IAPMO) to govern the installation, inspection and maintenance of HVAC (Heating, ventilating and air-conditioning) and refrigeration systems.

The UMC is developed using the American National Standards Institute's (ANSI) consensus development procedures. This process brings together volunteers representing a variety of viewpoints and interests to achieve consensus on mechanical issues.

The UMC is designed to provide consumers with safe mechanical systems while, at the same time, allowing latitude for innovation and new technologies. The public at large is encouraged to provide input for the development process. The code is updated every three years.

In 1926, a group of Los Angeles plumbing inspectors recognized that there were no uniform requirements for the installation and maintenance of plumbing systems. At that time, heating was done by boilers that piped the heat to radiators. Efficient air conditioning was not available. Widely divergent practices and the use of many different, often conflicting, plumbing codes by local jurisdictions led to plumbing systems that were incompatible and potentially dangerous. This underscored the necessity of developing a model code that could be uniformly applied across jurisdictions.

Two years later, the city adopted the first version of a uniform plumbing and mechanical code developed by the Los Angeles City Plumbing Inspectors Association (LACPIA) and based on the input from a committee of plumbing inspectors, master and journeyman plumbers, and mechanical engineers, assisted by public utility companies and the plumbing industry.

The ultimate product of this effort, the first Uniform Mechanical Code, was published by IAPMO, the new name for LACPIA, which was adopted in 1966 when the scope of mechanical work grew beyond plumbing and became more readily available in residential applications.) in 1967. Over the last fifty years, this voluntary code has been adapted by jurisdictions not only throughout the United States, but internationally as well. The consensus development process was first applied to the 2003 edition.

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