Establishes minimum regulations for mechanical systems using prescriptive and performance-related provisions. First introduced in 1996, the IMC was developed with broad-based principles that make possible the use of new materials, methods and design. Changes include: New and existing mechanical systems must be maintained in accordance with ASHRAE/ACCA/ANSI Standard 180. Parking garage exhaust now defined as environmental air. Includes specifications for grease reservoirs in commercial cooking exhaust duct systems. Includes requirements for underground grease ducts. Requires any combustible material in a return air plenum to be listed and labeled to verify compliance with ASTM E-84 or UL 723. Air dispersion systems are now allowed. New requirements for evaporative coolers. Don't forget to order the Turbo Tabs!