45 dBA Compliance

New Office Building
State of California
Department of Industrial Relations
4740 Allene Way, San Luis Obispo
Building Site falls within projected 60 dB airport noise contour.
This study determined compliance with California State
Building Code requirement for interior habitable spaces to be
at or below LEQ = 45 dBA.

Sound Level Meter, Exterior

Sound Level Meter, Interior

One hour Sound Levels, Interior / Exterior

The study was conducted in accordance with ASTM E966 - 04 Standard Guide for Field Measurements of Airborne Sound Insulation of Building Facades and Facade Elements.  The Outdoor-Indoor Transmission Loss (OITL) was measured by synchronous recording of A-Weighted sound levels outdoors and indoors, using the Traffic Noise method.

The one-hour sound levels are shown in the graph above.   Positions of sound level meters are shown below.

1.  At the top (red line) is the outdoor sound level (position X1 below).  

2.  The green line is a plot of synchronous sound levels in an exterior room (position X3 below)

3.  The blue line is a plot of sound levels in an interior room (X2 below)

Outdoor LEQ one hour is approximately 55 dBA.  Indoor LEQ one hour is approximately 35 dBA.  OITL is approximately 20 dBA.