{"operation":"document","citation":"49 CFR 171.9","title":"Rules of construction.","source_type":"regulation","agency":"Pipeline and Hazardous Materials Safety Administration","status":"current","official":true,"published_on":null,"effective_on":"2026-08-18","summary":"(a) In this subchapter, unless the context requires otherwise:\n\n(1) Words imparting the singular include the plural;\n\n(2) Words imparting the plural include the singular; and\n\n(3) Words imparting the masculine gender include the feminine;\n\n(b) In this subchapter, the word: (1) “Shall” is used in an ","machine_formats":{"json":"https://regulus.evalyn.ai/document/49-cfr-171-9.json","markdown":"https://regulus.evalyn.ai/document/49-cfr-171-9.md"},"app_url":"https://regulus.evalyn.ai/document/49-cfr-171-9","source_url":"https://www.ecfr.gov/on/2026-08-18/title-49/section-171.9","body":"(a) In this subchapter, unless the context requires otherwise:\n\n(1) Words imparting the singular include the plural;\n\n(2) Words imparting the plural include the singular; and\n\n(3) Words imparting the masculine gender include the feminine;\n\n(b) In this subchapter, the word: (1) “Shall” is used in an imperative sense;\n\n(2) “Must” is used in an imperative sense;\n\n(3) “Should” is used in a recommendatory sense;\n\n(4) “May” is used in a permissive sense to state authority or permission to do the act described, and the words “no person may * * *” or “a person may not * * *” means that no person is required, authorized, or permitted to do the act described; and\n\n(5) “Includes” is used as a word of inclusion not limitation.\n\n[Amdt. 171-32, 41 FR 15996, Apr. 15, 1976, as amended by Amdt. 171-32A, 41 FR 40630, Sept. 20, 1976; Amdt. 171-121, 58 FR 51528, Oct. 1, 1993; 75 FR 60338, Sept. 30, 2010]","truncated":false,"body_characters":897}