These requirements cover humidifiers rated 600 V or less@ and intended to be used in accordance with the National Electrical Code (NEC)@ ANSI/NFPA 70@ and the Rules of the Canadian Electrical Code (CEC)@ Part 1@ C22.1. These requirements cover humidifiers intended for residential and commercial use. This includes humidifiers of the centrifugal atomizing type@ evaporative-media type@ water-injection type@ steam type@ and the like. The humidifiers may be for installation in a room@ mounted on a wall or a ceiling@ or for duct or plenum mounting. These requirements apply to equipment that includes an electric heating element to heat air or water@ or both. These requirements do not apply to evaporative coolers that are also intended to be used for cooling. These requirements do not apply to portable@ electrode-type products@ such as vaporizers@ which are covered by the Standard for Electric Heating Appliances@ UL 499@ and the CSA Standard for Household Cooking and Liquid-Heating Appliances@ CAN/CSA-C22.2 No. 64.