NFPA 45-2019 Standard on Fire Protection for Laboratories Using Chemicals.
3.2.4* Listed. Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evalua- tion of services, and whose listing states that either the equip- ment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose. 3.2.5 Shall. Indicates a mandatory requirement. 3.2.6 Should. Indicates a recommendation or that which is advised but not required. 3.2.7 Standard. An NFPA Standard, the main text of which contains only mandatory provisions using the word “shall” to indicate requirements and that is in a form generally suitable for mandatory reference by another standard or code or for adoption into law. Nonmandatory provisions are not to be considered a part of the requirements of a standard and shall be located in an appendix, annex, footnote, informational note, or other means as permitted in the NFPA Manuals of Style. When used in a generic sense, such as in the phrase “standards development process” or‘ ‘standards development activities,” the term“standards” includes all NFPA Standards, including Codes, Standards, Recommended Practices, and Guides. 3.3 General Definitions. 3.3.1 Apparatus. Furniture, chemical fume hoods, centri- fuges, refrigerators, and commercial or made-on-site equip- ment used in a laboratory. 3.3.2 Auxiliary Air. Supply or supplemental air delivered near the outside face of a chemical fume hood to reduce room air consumption. 3.3.3 Baffle. An object placed in an appliance to change the direction of or to retard the flow of air, air- gas mixtures, or flue gases. [54, 2018]
3.3.12 Deflector Vane. An airfoi-shaped vane along the bottom of the hood face that directs incoming air across the work surface to the lower baffle opening. The opening between the work surface and the deflector vane is open even with the sash fully closed. 3.3.13 Educational Laboratory Unit. A laboratory unit that is under direct supervision of an instructor and used for educa- tional purposes for students through the twelfth grade. 3.3.14 Educational Occupancy. See 3.3.15 Exit Acess Corridor. A corridor used as exit access that leads to an exit that is separated from other parts of the building by walls. 3.3.16 Explosive Material. Any explosive, blasting agent, emulsion explosive, water gel, or detonator. 3.3.17* Face (of hood). The hood opening or the plane of the inside surface of the sash. 3.3.18 Face Velocity. The rate of flow or velocity of air moving into the chemical fume hood entrance or face, as measured a the plane of the chemical fume hood face. 3.3.19 Fire Separation. A horizontal or vertical fire resist- ance- -rated assembly of materials that have protected openings and are designed to restrict the spread of fire. 3.3.20 Flammable Gas. Any substance that exists in the gaseous state at normal atmospheric temperature and pressure and is capable of being ignited and burned when mixed with the proper proportions of air, oxygen, or other oxidizers. [99, 2018]
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