12989299 - Laserfiche WebLink

Home Browse Search

FIRE AND SMOKE PROTECTION FEATURES 2. Draftstopping is not required in buildings 718.5 Combustible materials in concealed spaces in Type I equipped throughout with an automatic sprinkler or II construction. Combustible materials shall not be per- system in accordance with Section 903.3.1.2, mitted in concealed spaces of buildings of Type I or II con- provided that automatic sprinklers are also stmction. installed in the combustible concealed spaces Exceptions: where the draftstopping is being omitted. 718.3.3 Other groups.In other groups,draftstopping shall 1. Combustible materials in accordance with Section be installed so that horizontal floor areas do not exceed 603' 1,000 square feet(93 m'). 2. Combustible materials exposed within plenums Exception: Draftstopping is not required in buildings complying with Section 602 of the Mechanical equipped throughout with an automatic sprinkler sys- Code. tem in accordance with Section 903.3.1.1. 3. Class A interior finish materials classified in accor- 718.4 Draftstopping in attics. In combustible construction, dance with Section 803. draftstopping shall be installed to subdivide attic spaces and 4. Combustible piping within partitions or shaft enclo- concealed roof spaces in the locations prescribed in Sections sures installed in accordance with the provisions of 718.4.2 and 718.4.3. Ventilation of concealed roof spaces this code. shall be maintained in accordance with Section 1203.2. 5. Combustible piping within concealed ceiling spaces 718.4.1 Draftstopping materials. Materials utilized for installed in accordance with the Mechanical Code draftstopping of attic spaces shall comply with Section and the Plumbing Code. 718.3.E 6. Combustible insulation and covering on pipe and 718.4.1.1 Openings.Openings in the partitions shall be tubing, installed in concealed spaces other than Me- protected by self closing doors with automatic latches nums,complying with Section 720.7. constructed as required for the partitions. 718.4.2 Groups R-1 and R-2.Draftstopping shall be pro- SECTION 719 vided in attics, mansards, overhangs or other concealed FIRE-RESISTANCE roof spaces of Group R-2 buildings with three or more REQUIREMENTS FOR PLASTER dwelling units and in all Group R-1 buildings. Draftstop- ping shall be installed above, and in line with, sleeping 719.1 Thickness of plaster The minimum thickness of gyp- unit and dwelling unit separation walls that do not extend sum plaster or Portland cement plaster used in a fire-resis- to the underside of the roof sheathing above. tance-rated system shall be determined by the prescribed fire Exceptions: tests.The plaster thickness shall be measured from the face of the lath where applied to gypsum lath or metal lath. I. Where corridor walls provide a sleeping unit or 719.2 Plaster equivalents. For fire-resistance purposes, 4, dwelling unit separation,draftstopping shall only inch (12.7 rum be required above one of the corridor walls. �) of unsanded gypsum plaster shall be deemed equivalent to /,,inch(19.1 rum)of one-to-three gypsum sand 2. Draftstopping is not required in buildings plaster or 1 inch(25 mm)of Portland cement sand plaster. equipped throughout with an automatic sprinkler 719.3 Noncombustible furring.In buildings of Type I and II system in accordance with Section 903.3.1.1. construction, plaster shall be applied directly on concrete or 3. In occupancies in Group R-2 that do not exceed masonry or on approved noncombustible plastering base and four stories above grade plane, the attic space fuming. shall be subdivided by draf[stops into areas not 719.4 Double reinforcement.Plaster protection more than 1 exceeding 3,000 square feet (279 m') or above inch (25 rum) in thickness shall be reinforced with an addi- � every two dwelling units,whichever is smaller. tional layer of approved lath embedded at least'/a inch(19.1 4. Draftstopping is not required in buildings nun)from the outer surface and fixed securely in place. equipped throughout with an automatic sprinkler Exception: Solid plaster partitions or where otherwise system in accordance with Section 903.3.1.2, determined by fire tests. provided that automatic sprinklers are also installed in the combustible concealed space 719.5 Plaster alternatives for concrete. In reinforced con- where the draftstopping is being omitted. Crete construction,gypsum plaster or Portland cement plaster 718.4.3 Other groups.Draftstopping shall be installed in is permitted to be substituted for 4, inch (12.7 nun) of the attics and concealed roof spaces, such that any horizontal required poured concrete protection, except that a minimum area does not exceed roof square feet(279 m�, thickness of /s inch(9.5 nun)of poured concrete shall be pro- vided in reinforced concrete floors and 1 inch (25 rum) in (C Exception: Draftstopping is not required in buildings reinforced concrete columns in addition to the plaster finish. equipped throughout with an automatic sprinkler sys- The concrete base shall be prepared in accordance with Sec- tem in accordance with Section 903.3.1.1. tion 2510.7. 2019 OREGON STRUCTURAL SPECIALTY CODE 153