All the petitioners-appellants are employed by the City of New York under the civil service title of “ Stationary Fireman ’ ’. Their appeal here is by our leave from a unanimous order of the Appellate Division, First Department, confirming a determination of the comptroller of the City of New York in which, after hearings, he dismissed complaints filed by petitioners under section 220 of the Labor Law. The comptroller held that petitioners are not in such employment as entitles them, under that statute, to the “ prevailing rate of wages ” mandated by the statute to be paid to “ laborers, workmen or mechanics ” on public works. The argument against petitioners runs like this:
(1) That section 220 is available only to persons employed in the construction, maintenance or repair of public works (see Matter of Pinkwater v. Joseph, 300 N. Y. 729; Matter of Dinan v. Joseph, 304 N. Y. 696; Matter of Miele v. Joseph, 305 N. Y. 667).
(2) That the test of whether or not a city employee is engaged in the construction, maintenance or repair of public works is the municipal civil service commission description of his job duties *67(Matter of Flannery v. Joseph, 300 N. Y. 149; Matter of Dinan v. Joseph, supra).
(3) That the civil service description of the job of stationary fireman: “ To fire high pressure boilers with coal or oil; operate by hand low pressure boilers, burning either No. 5 or No. 6 oil; perform related work ”, describes the operation of a mechanical facility only, and not construction, maintenance or repair work.
(4) That, because of the above, evidence was inadmissible, and the comptroller excluded it, to show that the actual job duties of these petitioners included the making of repairs on boilers.
Despite the exclusion from evidence, at the hearings, of proffered proof that these men regularly made repairs on the boilers they fired, the record before us contains allegations and admissions that it is regularly a part of the duties of such stationary firemen to make some of the repairs on their boilers even though there is a separate civil service classification of “ Boilermaker ”.
Begardléss of the complexity of much of the case law as to the impact of section 220, this at least seems to be settled: that those whose work has to do with the construction and maintenance of the fabric and essential parts of public buildings are entitled to prevailing wages even though their connection with building construction and maintenance is as minimal as that of the sign painters and sign letterers who were held entitled to prevailing wages in Matter of Miele v. Joseph (supra). We think these petitioners are entitled to no less, and for these reasons:
(1) It is undisputed that they do regularly make boiler repairs — that is, they repair heating facilities which are necessary parts of the buildings.
(2) In so doing, they are not working “ out of ” their civil service titles, as was the case in Matter of Flannery v. Joseph (supra).
(3) The job definition here involved includes not only firing and operating boilers but also “ related work ” and it is undisputed that the related work includes a substantial amount of boiler repairs.
*68(4) These petitioners, as stationary firemen, have been classified by the municipal civil service commission in Part 38 of the competitive class, in a salary grade “ at the prevailing rate of wages * * * as determined by law ”. We have indicated that grading is a controlling factor in the fixing of compensation for incumbents of positions in the graded services of the competitive class (see Matter of Corrigan v. Joseph, 304 N. Y. 172, 182; also Civil Service Law, § 6). While the validity of such grading may be challenged in a direct suit against the officials who adopted and approved the grade, such grading except in such a suit, must be deemed valid in any subsequent administrative or judicial proceeding wherein any collateral attempt is made to question the legality of the grading (see Matter of Corrigan v. Joseph, supra, p. 186, note). Therefore, the grading of the petitioners in Part 38 of the competitive class at the prevailing rate of wages, not directly challenged, entitles them to section 220 relief, procedurally, rather than relegating them to suits at law for those same prevailing wages.
(5) Section 220 itself contains, in its subdivision 4 (par. a), an exclusion of “ Stationary firemen in state hospitals ”, which certainly suggests that other stationary firemen, like these petitioners, are under the statute.
(6) The work of petitioners is at least as closely related to the preservation and maintenance of physical structures as were the sign painters in Matter of Miele v. Joseph {supra).
The order appealed from should be reversed, with costs, and the matter remitted to respondent comptroller, for further proceedings not inconsistent with this opinion.
Lewis, Oh. J., Conway, Dye, Fuld and Froessel, JJ., concur; Van Voorhis, J., taking no part.
Order reversed, etc.