These requirements cover aluminum electrical metallic tubing (EMT) and elbows in trade sizes 3/8 ?C 4 (12 ?C 103) for use as a metal raceway for the installation of wires and cables in accordance with the National Electrical Code. The values in parentheses are metric designators of tubing. Steel tubing provided with an exterior coating of zinc or a zinc-based@ nonmetallic@ or other alternate corrosion-resistant material and an interior coating of an organic or zinc material@ is covered by the Standard for Electrical Metallic Tubing ?C Steel@ UL 797. A product that contains features@ characteristics@ components@ materials@ or systems new or different from those covered by the requirements in this standard@ and that involves a risk of fire or of electric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A product whose features@ characteristics@ components@ materials@ or systems conflict with specific requirements or provisions of this standard does not comply with this standard. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development@ revision@ and implementation of this standard.