How To Achieve 1 Hour Fire Rated Wood Roof Trusses

Screw fastened perpendicular to lower chord of wood trusses of 2 x 4 38 mm x 89 mm.

How to achieve 1 hour fire rated wood roof trusses. Floor joists vary in depth but maintain 16 o c or less. Ibc table 721 3 item 21 1 1 describes a single prescriptive 1 hour rated floor or roof assembly that includes wood trusses. Concrete with cellular steel 3 hr. Wood joists wood i joists floor trusses and flat or pitched roof trusses spaced a maximum 24 o c.

Gypsum wallboard roof ceilings wood framing pitched roof truss 11 1 hr. With 1 2 wood structural panels with exterior glue applied at right angles to top of joist or top chord of trusses. 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. 12 x 24 2 x 4 8 w10 x 25 beam floor units and beam support 3 hr.

Urb concealed grid system and tile. Applied to bottom chord of each truss floor or roof 1 hour. 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. I believe adding 5 8 drywall on both sides is the answer one hour fire rating for a truss drywall contractor talk.

Ul p533 roof ceiling one layer 5 8 15 9 mm fire shield c ga rc 2603 wallboard attached to 1 2 12 7 mm resilient furring channel spaced 12 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. 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.

3 4 fr 83 12 x 12 z runners fluorescent type none 2 1 2 concrete. Fire rated suspended ceiling wood truss council of america floor or roof fire notes 1. 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. Ul u338 figure 17 3 3.

For additional information on fire resistance rated assemblies see sbca research report 1509 01. 2x4 studs spaced 24 o c. No minimum joist size is given except that it needs to be adequate for structural loads. Assemblies include ducts dampers lighting or other fixtures in the tested assembly.

Type x gypsum board is wallboard to which non combustible fibers have been added. See full report for details.