NBC Procedure for Sawn Lumber

Part 9 of the National Building Code of Canada (NBC) includes a vibration criterion in section A-9.23.4.2.(2) . The calculations for the span tables in Part 9 use the following simplified static analysis method of estimating vibration-acceptable spans.

1. The span S_i that results in a 2 mm deflection of a single joist supporting a 1 kN concentrated load at midspan is calculated.
2. The span S_i is multiplied by a factor K to determine the "vibration-controlled" span for the entire floor system.

This factor "K" depends on the subfloor sheathing thickness, bridging of joists, and connection of the subfloor to the joists,

Although the Canadian Wood Council has published extended span tables incorporating the vibration criteria for various residential floor system configurations, Sizer provides you with the ability to check vibration for floor joists used in non-residential applications.

Note: The vibration criterion is only applicable to simply supported 2" nominal thickness lumber joists.