How To Achieve 1 Hour Fire Rated Wood Roof Trusses

2x4 studs spaced 24 o c.

How to achieve 1 hour fire rated wood roof trusses.

Floor joists vary in depth but maintain 16 o c or less. See full report for details. I believe adding 5 8 drywall on both sides is the answer one hour fire rating for a truss drywall contractor talk. Ibc table 721 3 item 21 1 1 describes a single prescriptive 1 hour rated floor or roof assembly that includes wood trusses.

Screw fastened perpendicular to lower chord of wood trusses of 2 x 4 38 mm x 89 mm. Fire rated suspended ceiling wood truss council of america floor or roof fire notes 1. Wood joists wood i joists floor trusses and flat or pitched roof trusses spaced a maximum 24 o c. Ibc section 722 6 could be used to calculate up to a 1 hour rating for a wood frame wall floor or roof assembly.

1 hour rated wall bearing or non bearing with optional insulation with a finish rating of 20 minutes for 1 layer of gypsum each side for non bearing walls or 59 minutes with 2 layers of gypsum each side for bearing walls on a single gable truss with 2x3 o c. No minimum joist size is given except that it needs to be adequate for structural loads. The reluctance to rely on approved test results is unwarranted as explained in section 17a and section 17b of sbca s metal plate connected wood truss handbook. Ibc table 722 6 2 2 allows 10 minutes for wood floor or roof joists at 16 o c.

Type x gypsum board is wallboard to which non combustible fibers have been added. Assemblies include ducts dampers lighting or other fixtures in the tested assembly. 276 fire rated ceiling assemblies suspension ceiling designs floor ceiling designs a003 3 hr. Urb concealed grid system and tile.

Trying to use section 721 6 1 of the ibc to acheive a 1 hour rating of existing floor assemblies in 20 buildings by using only 1 layer of 5 8 drywall. How do i get a 1 hour fire rating for the truss. With 1 2 wood structural panels with exterior glue applied at right angles to top of joist or top chord of trusses. Concrete with cellular steel 3 hr.

Fire resistance rated truss assemblies. For additional information on fire resistance rated assemblies see sbca research report 1509 01. Ul u338 figure 17 3 3. 3 4 fr 83 12 x 12 z runners fluorescent type none 2 1 2 concrete.

According to the book commercial drafting and detailing a typical one hour fire rated wall consists of 2x4 studs spaced 16 inches from the center of one stud to the center of the next covered by 5 8 inch type x gypsum board. 12 x 24 2 x 4 8 w10 x 25 beam floor units and beam support 3 hr.