211.0 I – — 2025 California Mechanical Code

Immediately Dangerous to Life and Health (IDLH). A concentration of airborne contaminant’s, normally expressed in parts per million (ppm) or milligrams per cubic meter (mg/m [3] ), that represents the maximum level from which one is capable of escaping within 30 minutes without escapeimpairing symptoms or irreversible health effects. This level is established by the National Institute of Occupational Safety and Health (NIOSH).

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Incinerator. An appliance or combustion chamber for the reduction, by burning, of rubbish, garbage, and other wastes.

[NFPA 211:3.3.91]

Industrial Heating Equipment. Includes appliances, devices, or equipment used, or intended to be used, in an industrial, manufacturing, or commercial occupancy for applying heat to any material being processed, but shall not include water heaters, boilers, or portable equipment used by artisans in pursuit of a trade.

Insanitary Location. An area, space, or room where the air is unfit or undesirable for circulation to occupiable parts of a building.

Interconnected. Mutually assembled to another component in such a manner that the operation of one directly affects the other or that the contents of one specific duct system are allowed to encounter or contact the products being moved by another duct system. [NFPA 96:3.3.34]

Interlock. A device that senses a limit or off-limit condition or improper sequence of events and shuts down the offending or related piece of equipment or prevents proceeding in an improper sequence in order to prevent a hazardous condition from developing.

Intermittent Pilot. A pilot that burns during light-off and while the main burner is firing, and that is shut off with the main burner.

Interrupted Pilot. A pilot that burns during light-off and that is shut off during normal operation of the main burner.