Plenum Panels™ are predicted to have significantly superior resistance to objectional vibration such that vibration is not the controlling factor for design and therefore, the full strength can be utilized in both single and double plenum configurations.
Vibration is often the controlling factor for allowable spans for solid CLT floor panels because the natural frequency is usually in the 9-10 Hz range and unsatisfactory for human perception. As a result, spans of solid CLT panels must often be shorter to avoid objectional frequencies. Shorter spans for vibration is not good utilization of wood and strength.
Plenum Panels are much lighter than solid CLT panels with a weight of 5 to 15 psf compared to 12-37 psf – about 60% lighter when compared to solid panels. This decrease in weight in combination with a slight decrease in Moment of Inertia (I) yields a calculated natural frequency of 20 to 24 Hz based on the formula below.
Using this formula and substituting the Plenum panel properties, there is a predicted increase in frequency of approximately 2 times soldi CLT because of the smaller area and slightly reduced moment of inertia.
This results in an expected natural frequency of approximately 20 Hz for Plenum Panels which is significantly outside the objectionable range of 5-10 Hz. The vibration resistance is further enhanced by the damping effect of the shear matrix in Plenum Panels.