Vibration Isolation Curbs

Vibration Isolation Curbs are fully integrated roof curb and vibration isolation system to reduce the transmission of vibration from the roof top mounted HVAC unit (RTU) to the building structure.

Transmitted vibration can cause unwanted noise levels throughout the building and the best way to reduce that transmission is through isolation mounting systems that have a negligible damping coefficient.  Elastomeric Isolators tend to have high damping coefficients, which is why we use only metal spring isolators in our products.  The table below shows the vibration transmission from the HVAC unit to the building structure as a percentage.  The data is presented as a function of the forced frequency of the unit and the deflection of the springs in a low damping design such as the Plenums Vibration Isolation Curb.  We offer static deflection up to 2 inches, but the 1-inch deflection is sufficient for most applications.   The highlighted green cells indicate the theoretical, zero damping, operating range of Plenums Vibration Isolation Products.