Except as is otherwise provided in this section, partitions in buildings of first, class construction shall be constructed of the materials and in the manner herein specified: -

Par. 1. - (a) Brick in cement mortar;

Par. 2. - (6) Concrete, consisting of one part Portland cement and not more than three parts of sand and six parts of stone or gravel, not less than three inches thick if properly reinforced with steel, nor less than four inches thick otherwise;

Par. 3. - (c) Cinder concrete, consisting of one part Portland cement and not more than three parts of sand and six parts of cinders, not less than four inches thick if properly reinforced with steel, nor less than five inches thick otherwise;

Par. 4. - (d) Hollow terra cotta blocks, laid in cement mortar, not less than three inches thick;

Par. 5. - (e) Hollow concrete blocks, of either stone or cinder concrete laid in cement mortar, not less than three inches thick;

Par. 6. - (f) Solid or hollow blocks consisting of gypsum containing not more than twenty-five per cent by weight of cinders, asbestos fiber, wood chips or vegetable fiber, laid in gypsum plaster or cement mortar tempered with lime, not less than three inches thick;

Par. 7. - (g) Metal lath on a steel studding covered with Portland cement mortar or gypsum plaster, of a finished thickness of not less than two inches in the case of solid partitions, nor less than three inches in the case of hollow partitions; or

Par. 8. - (h) Any material or form of construction that may be approved by the commissioner if conforming to the requirements of the fire test hereinafter prescribed. But nothing in this section shall prevent the erection, in the discretion of the commissioner, of partitions of pressed metal and glass or of temporary partitions of wood and glass within rooms or spaces enclosed by fireproof partitions or walls.

Par. 9. - The thicknesses as above described are for partitions up to fifteen feet in height, and they shall be increased in thickness one inch for every additional eight feet or fraction thereof. If partitions are not plastered on both sides, the thicknesses shall be one inch greater than those above specified.

Fireproof Partition Support

Par. 10. - Construction. - Unless built as approved masonry walls, partitions in fireproof buildings shall be independently supported at each floor. They shall be keyed, or otherwise securely fastened to the ceilings, and, when necessary, shall be stiffened with suitable steel uprights securely fastened to floor and ceiling. Partitions enclosing hallways or toilet rooms and other permanent partitions shall not rest on wood flooring but shall start on the fireproof construction of the floor. In the upper story, where there is a space between the ceiling of the top floor and the roof, partitions need not extend above the ceiling.

Par. 11. - Tests of Fireproof Partitions. - In testing the fireproof qualities of any partition construction, a vertical panel not less than fourteen feet long and nine feet high shall be subjected to a continuous fire for not less than one hour at an average temperature of seventeen hundred degrees Fahrenheit, during the latter half hour, followed by an application for not less than two and one half minutes of a hose stream from a one and one eighth inch nozzle at thirty pounds nozzle pressure, without the passage of flame during the test.

[1918, c. 179, sect. 14, Special Act.]