History of the Uniform Mechanical Code:
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.
The 2012 edition is the fourth edition developed under the ANSI consensus process. Contributions to the content of the code were made by every segment of the building industry. The 2012 Uniform Mechanical Code is supported by the American Society of Sanitary Engineering (ASSE), the Mechanical Contractors Association of America (MCAA), the Plumbing-Heating-Cooling Contractors National Association (PHCC-NA), the United Association (UA) and the World Plumbing Council (WPC).