LEC 2012 covers Packaged Plumbing and Mechanical Systems (PPMS), also known as skid systems, that are designed to inactivate and disinfect waterborne pathogens and microorganisms within hot water distribution systems from replicating and infecting humans. PPMSs combine devices that are typically located in a commercial or industrial building's mechanical room or basement. These systems include a water heater and distribution mixing valve, or water heater with integral temperature control device, an ultraviolet treatment system that treats incoming and recirculating water, filters, an anti-scaling device, chemical injection connections, and a connection to drain.

The PPMS shall include a programmable controller that manages the disinfection and control of the PPMS. The controller includes:

• Ability to send regular and as-needed maintenance alerts;
• Ability to send local and remote alerts;
• Connectivity to external building automation systems (e.g. MODBUS and BACnet).