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  • Spectra Tech Ltd: Noise Criteria (NC) (PNC) Curve Onsite Field Testing Services Nationwide: ANSI/ASA S12.2, HVAC System / Environmental Noise, Richard Lemker, Nationwide, Ohio, Indiana, Kentucky, Cincinnati, Dayton, Columbus, Springfield, Bowling Green, Knoxville, Portsmouth, Louisville, Lexington, Indianapolis, Frankfort, Lima, Bloomington, Huntington, WVA, OH, IN, KY

    Spectra Tech employes sophisticated equipment and software to automatically measure and document the Noise Criteria (NC) or Preferred Noise Criteria (PNC) Curve values of interior noise, primarily resulting from the building's HVAC system operation. We can also provide assistance in designing solutions to reduce excessive noise.

    • The Noise Criteria Curves were developed in cooperation with ASHRAE to form a universal standard by which HVAC noise could be quantified.
    • The test consists of recording the average unweighted (fast response) sound levels for each octave frequency band between 63 Hz and 8,000 Hz (8KHz) while the building's mechanical systems are in their typical operating mode.
    • The test results are plotted over a family of reference curves. The corresponding value of the plot at its highest level in any octave band is the NC or PNC value.
    • Plot / Print Test Results: We can provide documentation of test results by plotting / printing the test values on paper, and / or provide the reslts in PDF format.

    For a comprehensive list of acoustical measurement variables and criteria that can be measured and / or computed, please visit Detailed Measurement Specifications & Definitions

    For specifications on our primary audio test equipment, please visit Audio Test System Specifications


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