This is a complaint under G. L. c. 148, § 36, charging the defendant, as owner of a designated building in Boston, in which four or more persons were usually employed above the second story within rooms used in the manufacture of paper boxes, with having failed within six months after service of notice from the fire marshal to that effect to equip said building with automatic sprinklers.
The statute is not open to objection on constitutional grounds. It plainly is a regulation designed to protect persons working upon inflammable material in rooms higher than the second story from the peril of fire. It requires the installation of safety appliances in buildings where rooms in the third or higher stories are used for the manufacture of wooden, rattan or cane goods or other substances or stuffs likely to become easily ignited, fire in which would be peculiarly difficult to extinguish when once started, and in which flames might be expected to spread with dangerous rapidity. It is obviously enacted in the interests of public health and public safety. The statute relates only to the use of an existing building for specified dangerous occupations. *141It prohibits such use after seasonable notice unless the safety appliances are installed. Ample time after service of the notice is allowed for change of the occupancy to a less hazardous business if that is preferred to installing the equipment required. It establishes no arbitrary or inflexible rule for the alteration of existing structures, lawful in every particular when erected. See Commonwealth v. Alger, 7 Cush. 53, 103. Compare Opinion of the Justices, 237 Mass. 598, and cases collected at pages 608 to 610. It is confined in its operation to providing safety appliances for buildings above a certain height used for occupations regarded by the general court as subjecting those engaged therein to peculiar risk from fire. Appropriate regulation of this kind comes within the principle of numerous decisions. Commonwealth v. Roberts, 155 Mass. 281. Perry v. Bangs, 161 Mass. 35. Commonwealth v. Hubley, 172 Mass. 58. Commonwealth v. Maletshy, 203 Mass. 241, 245. Storer v. Downey, 215 Mass. 273. Baker v. Horan, 227 Mass. 415, 421. Stevens, landowner, 228 Mass. 368. Chase v. Proprietors of Revere House, 232 Mass. 88. Wheeler v. Boston, 233 Mass. 275. Commonwealth v. E. E. Wilson Co. 241 Mass. 406. The statute here involved distinguishes the present case from Durgin v. Minot, 203 Mass. 26, Goldstein v. Conner, 212 Mass. 57, Kilgour v. Gratto, 224 Mass. 78, Cawley v. Northern Waste Co. 239 Mass. 540, and decisions of that character.
The complaint conforms to the terms and follows in substance the phraseology of G. L. c. 148, § 36, under which it is drawn. There is provision in § 41 of the same chapter that no rule or order shall be made or enforced which requires an expenditure by the owner or occupant of more than five per cent of the last annual assessed valuation of the land and buildings to which the rule or order refers. No averment as to the cost of repairs was made in the complaint and no proof as to the matter was offered by the Commonwealth. It was said by Chief Justice Gray in Commonwealth v. Jennings, 121 Mass. 47, at page 49, “It is a general rule of pleading, that when an exception or proviso is embodied in the clause which defines the offence, or, as it is commonly called, the enacting clause, it must be negatived in the indictment; but that if it is only found in a subsequent distinct clause of the same or another statute, it need not be so negatived.” Commonwealth v. Maxwell, 2 Pick. 139. Commonwealth v. Boyer, 7 Allen, 306. *142Commonwealth v. Shannihan, 145 Mass. 99. That principle is applicable to the case at bar. The limitation as to the expense is not incorporated into the description of the substance of the offence but occurs in a subsequent section. Violation of its terms is matter of defence. No allegation or proof in this respect is required of the Commonwealth in the first instance.
The provisions of R L. c. 148, §§ 28 to 50, are operative in the city of Boston without acceptance by the city council of Boston. This is plain from the definition of the Metropolitan District in § 28. See St. 1914, c. 795, §§ 1, 26, 28.
The notice from the State fire marshal served upon the defendant, after reciting the use of the building for manufacture of paper boxes and the storage of paper and the employment of four or more persons above the second floor, required the defendant to equip parts of the building "with automatic sprinklers in a manner satisfactory to the Building Commissioner of the City of Boston.” This notice was not in conformity to the statute. The type of sprinkler and manner of installation are by the terms of the notice made wholly subject to the untrammelled discretion of the building commissioner of the city of Boston. The notice is objectionable in at least three respects: (1) The statute confers no authority upon the fire marshal to make any delegation of power or duty. Commonwealth v. Staples, 191 Mass. 384. Brown v. Newburyport, 209 Mass. 259, 266. Cawley v. Northern Waste Co. 239 Mass. 540, 543. See Commonwealth v. Slocum, 230 Mass. 180, 190. (2) Attempt to vest an untrammelled discretion in a public officer as to improvement of property without some rule for guidance has been often held void. Newton v. Belger, 143 Mass. 598. Commonwealth v. Maletshy, 203 Mass. 241. (3) The notice was vague and indefinite in requiring the installation of a mechanical device to conform to the satisfaction of a city officer without affording by reference or otherwise any guide. It is fair to afford to the landowner or occupant required to make expensive improvements some guide, rule or information as to what he must do and the manner in which it is to be done, in order that he may have a basis for knowing how to comply with the requirement and when he has satisfied the law. General Baking Co. v. Street Commissioners, 242 Mass. 194.
It is not necessary to determine what if any jurisdiction the *143building commissioner of the city of Boston possesses in the premises. See St. 1907, c. 550, §§ 1, 2, 9, 13, 104, 111; Commonwealth v. Hayden, 211 Mass. 296. It was not possible for the fire marshal by his notice to enlarge or curtail that jurisdiction in any respect. No provision of St. 1907, c. 550, has been called to our attention and we have discovered none which purports to confer upon the building commissioner of the city of Boston the unlimited power implied in the notice of the fire marshal. Williamson v. United States, 207 U. S. 425, 462.
The construction put upon somewhat similar words in Sawyer v. State Board of Health, 125 Mass. 182, 187, manifestly is to be confined to the peculiar facts there disclosed and cannot reasonably be extended to a case like the present. It follows that a verdict of not guilty ought to have been directed. The ground upon which this decision rests renders it unnecessary to consider the other points urged by the defendant.
Exceptions sustained.