Unit Operation or Unit Process : A segment of a physical or chemical process that might or might not be integrated with other segments to constitute the manufacturing sequence
NFPA 1 Fire Code, National Fire Protection Association (NFPA), MA, USA 2009 ed. https://law.resource.org/pub/us/code/ibr/nfpa.1.20 03.pdf, (Code: Nat Fire Protection Association Fr&LfSf Requir - Amer) {171 NFC}