Par. 1. - All structural metal supporting or forming part of the frame, floors, roof or columns of any building, except as otherwise exempted in this act, shall be protected against the effect of heat.

Protection shall consist of: -

Par. 2. - (a) Concrete. - Cast in forms around and in direct contact with the structural members and reinforced with iron or clamps or hangers or with wires in such a manner as to form a thorough bond. Concrete filling may be deemed protection for the upper flanges where arch construction is used;

Par. 3. - (b) Terra Cotta. - Clamped in place with steel clamps or wrapped securely with number twelve galvanized iron wire or metal lath in such manner as to hold each block in place, set in mortar no poorer than one part natural cement and two parts sand and (except where arches abut) plastered with the same mortar at least one half inch thick, and at least thick enough to make the entire protection as thick as required in paragraph three. Terra cotta blocks may be hollow but each face shall be solid, and no shell or web shall be less than three quarter inches thick;

Par. 4. - (c) Brickwork. - Set in cement mortar;

Par. 5. - (d) Any material or form of construction that will resist the action of flames and a heat of seventeen hundred degrees Fahrenheit for at least two hours without raising the temperature of the material to be protected above five hundred and fifty degrees Fahrenheit, through a thickness of two inches, as determined by fire and water tests for fireproofing construction adopted by the American Society for Testing Materials.

Par. 6. - This protection shall be, unless it is otherwise provided herein, at least three quarter inches thick and at least of the thickness named in the following table: -

On columns carrying masonry walls: -

One and one half inches against the edges of flanges;

Four inches elsewhere. On columns carrying floors or roofs or both: -

One and one half inches against the edges of flanges;

Three inches elsewhere. On beams, girders or trusses carrying masonry walls: -

One inch on top:

Two inches elsewhere. On beams, girders, or trusses carrying floors or roofs or both: -

One inch on top;

One and one half inches elsewhere. On beams deeper than fifteen inches or having a flange width of more than seven and one half inches: -

One inch on top;

Two inches elsewhere. On lugs, brackets, braces and similar minor construction members and beyond the tips of rivets: -

Three quarters of an inch.

Exterior Isolated Columns

Par. 7. - About isolated columns on the exterior of buildings, the thickness of protection may be reduced to one inch, when the same is covered with an outer shell of cast iron or steel.

Plaster on Metal Lath Not Fire Protection for Steel or Iron

Par. 8. - Plaster on metal lath shall not be considered as a fire protection for steel or iron structural members, except that where suspended ceilings of metal lath and plaster leave not less than one inch of air space against the protective covering of such structural member, the protective covering may be one inch in thickness.

Par. 9. - Metal lath and plaster used for the requirements of this section shall have a total thickness, not counting clinches, of not less than three quarters of an inch.

Pipes, etc., Not to be Embedded

Par. 10. - No pipes, wires, cables or other material shall be embedded in the required fireproofing of columns or other structured members.

The above requirements as to fire protection shall not apply in the following cases: -

Par. 11. - (a) Structural metal in second or third class buildings in any case in which wood without fire protection would be permissible under this act.

Par. 12. - (b) Structural metal which faces on enclosed spaces that are strutted up or hung down from floors or roofs where the tops, bottoms and walls or partitions of such spaces are protected against fire on the outer side, as required elsewhere in this act.

Par. 13. - (c) Lintel angles under stone or brick unless over ten feet span.

Par. 14. - (d) Buildings built in whole or in part of a better class of construction than is required by this act shall be required to have only such protection for structural metal as would be required in a building of the type that would be allowed in the given case.

Par. 15. - (e) Metal work in a non-bearing partition, and for furrings and metal used only to support finish or equipment, and for metal of stair construction, suspension rods for balconies, steel work of theatre stages, fly galleries and rigging lofts.

Par. 16. - (f) Metal, other than columns, carrying no other loads than ceilings, or suspended balconies not over eight feet wide. When a suspended ceiling is used it shall be of metal lath and plaster with hanging rods, ties, stiffening, and the like, of metal.

Alterations - Fireproofing to be Satisfactory to Commissioner

Par. 17. - In work in connection with alterations of existing buildings, the character and amount of protection for steel and iron work shall be made satisfactory to the commissioner.

Par. 18. - Whenever any protective material or structural metal is, in the opinion of the commissioner, liable to injury by trucks or merchandise, wood or metal guards shall be applied as he may require.

Firestopping - Third Class Buildings

Par. 19. - In buildings of third class construction the exterior walls at each floor level, and all spaces between joists over girders and bearing partitions, and from plate to roof boarding, shall be firestopped with masonry or metal.

Firestopping in Second Class Buildings

Par. 20. - In buildings of second class construction spaces between strap furring on brick walls shall be filled for a distance of five inches below and five inches above the floor beams with mortar, and all spaces between joists over girders and bearing partitions, and from plate to roof boarding shall be firestopped with masonry not less than four inches thick.

Roof, Stairway and Chimney Firestopping

Par. 21. - In buildings of second or third class construction spaces between rafters, over furring enclosing spaces under the roof, shall be firestopped with wood or metal, and spaces between stringers of stairs and joists of landings, unless stairs are unceiled or of incombustible materials, shall be firestopped with masonry or metal or not less than seven eighths of an inch of wood, at least twice in each flight of stairs. All spaces around chimneys shall be thoroughly firestopped with sheet metal, metal lath and plaster, or masonry.

Firestopping - How Applied

Par. 22. - Firestopping shall completely fill all openings where it is applied; all chases or enclosures for pipes shall be firestopped adjacent to other required firestopping and by the same materials, except that metal lath and plaster' may be used.

Rat-proofing

Par. 23. - No building operations shall be permitted which will create unnecessary permanent spaces where rats will find refuge from their enemies and breed.

Firestopping Floors

Par. 24. - In every building of second or third class construction each floor shall be thoroughly stopped by a continuous layer of asbestos fabric, magneso-calcite or other fire-resisting material approved by the commissioner.

Par. 25. - Furnaces and Smoke Pipes. - The tops of all heating furnaces and smoke pipes shall be at least one foot below the nearest wooden beams or ceilings. All ceilings immediately over a furnace or boiler, and for six feet on each side thereof, and all ceilings over indirect radiators shall, except under fireproof floors, be metal-lathed and plastered.

Par. 26. - Register Boxes. - All hot-air register boxes in the floors or partitions of buildings shall be set in soapstone or equally fireproof borders and not less than two inches in width, shall be made of tin plate, and shall have double pipes and boxes properly fitted to the soapstone. Hot-air pipes and register boxes shall be at least one inch from any woodwork, and register boxes shall be fifteen inches by twenty-five inches or larger, and their connecting pipes shall be two inches from any woodwork. If indirect hot water or indirect steam heat is used, the commissioner may modify or dispense with the foregoing requirements. Par. 27. - Vent and Smoke Pipes. - All vent or smoke pipes for stoves, furnaces or heaters, not including gas stoves, hereafter installed shall be placed not nearer than twelve inches to any lath, plaster or board partition, ceiling or woodwork. Where such pipes pass through a lath and plaster or board partition, they shall be protected by ventilated metal collars at least six inches larger in diameter than the pipe. Where such pipes enter the chimney, the opening into the same shall be protected by a metal collar built at least four inches into the brickwork of the chimney. No such pipe shall pass through the roof or exterior wall of any building. Such pipes when within eighteen inches of a ceiling shall be protected by having the ceiling over them, and at least two feet wide, wire-lathed and plastered, or by having a shield of metal of the same width hung from the floor timbers, and at least six inches distant therefrom. Vent pipes to gas stoves, if placed nearer than three inches to any woodwork or lath and plaster partition, shall be protected with incombustible material.

[1918, c. 179, sect. 13, Special Act.] [1921, c. 60, sect. 2.]