A document that is similar in content and structure to a code or standard but that contains only nonmandatory provisions using the word "should" to indicate recommendations in the body of the text
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}