Testing & Measurement of Acoustics, Noise, Sound and Vibration

Measurement & Testing Engineers and Acoustical Engineers & Consultants

Professional Sound, Noise & Vibration Measurement and Testing Engineering Services:

Thornton Acoustics & Vibrations, Consulting Engineers in Acoustics Vibrations and Noise Control, of Pittsburgh PA provides noise and vibration testing and measurement engineering services for sound, acoustics, noise, and vibration throughout North America with a prominence in Pittsburgh PA, Cleveland OH, NY, MD, WV, and VA. The firm uses advanced approaches to make measurements and conduct tests by investing in top-of-the-line and state-of-the-art measurement instruments and testing equipment. The firm owns a comprehensive inventory of technically advanced instruments, transducers, and test equipment (no rentals) used for virtually all types of acoustical, noise, and vibration measurement or testing situations where the state-of-repair of the instruments and their calibration is explicitly known.

The firm’s highly qualified noise and vibration engineers possess a wide array of instruments and measurement techniques that are needed to properly measure the sources and paths of noise and vibration and its contribution to receiver locations. Measurements are also used to characterize a source for the purposes of comparing it with some standard or client requirement. More often than not, the experience and knowledge of the firm’s sound and vibration engineer will be the key to accurately characterizing the source or item under test. Measurements made by the acoustical consultant may vary from a simple noise or vibration measurement at a single location to complex measurements that determine the sound power level or map out the vibration levels.

Instruments, equipment, and procedures are consistent with good practice and recognized standards as appropriate. Thornton Acoustics & Vibrations follows acoustical, noise, and vibration evaluation procedures that are consistent with good practice and the appropriate parts of the American National Standard Institute's Methods for the Measurement of Sound Pressure Levels, ANSI S1.13-1971 and the Method for the Physical Measurement of Sound, ANSI S1.1-1963 (R1971). For community noise measurements, appropriate parts of ASTM Measurement of Outdoor A-Weighted Sound Levels, E1014-84, are used. Dr. Thornton, a principal, is well known and respected in North America for his high level of expertise as an “Individual Expert” on the prestigious ANSI S12 Standards group.

All sound-level measurements are made with precision instruments that include two Bruel & Kjaer 2250 Sound Level Meters equipped with octave and third octave bands, narrow band filters, data logging, and sound recording. These Type I instruments meet the strict requirements for precision work. All standard acoustical & noise metric are able to be measured. These include the LA, LMAX, LMIN, LNs, LDN, and LEQ. Real time octave and third octave band measurements are done with the B&K 2250 SLM with 120 dB dynamic range or with the B&K Pulse System with a 160 dB dynamic range Dyna-X front end, or an HP 35670A Dynamic Analyzer. The Pulse system allows all of these metrics to be measured in the octave and third-octave bands at the same time. It also allows measurements with different weighting, and averaging times such as the fast and slow responses at the same time. The real time signal can be stored on disk and post-processed if other issues come up after testing has been completed. The limitations of the Pulse are only on the user’s imagination and computer’s memory limits. The B&K 2250 SLM is able to measure the actual noise that is occurring at the time of the measurement and store it in the memory banks along with measured data. Both the B&K Pulse and 2250 SLM are state-of-the-art for noise measurement.

Vibrations are measured with PCB accelerometers and force hammers. Measurements are processed with a B&K Pulse System which has 160 dB Dyna-X Front-End. With a 160 dB dynamic range, data can be collected without ranging problems common to adjustable range analyzers. Transducers (excluding heavy ones) are field calibrated with a B&K vibration calibrator.

Spectral analysis is done in real time with a B&K Pulse System with the backup support of a Hewlett Packard 35670A Dynamic Analyzer. Simple field FFT measurements can be made with the B&K 2250 sound level meter. The B&K Pulse system allows many different types of analysis to be performed at the same time along with the retention of the raw time history data for follow-up post-processing if it is needed.

Tape recorders are not normally used but two DAT recorders are available to record and document events at request of the client. The B&K 2250 meters are also able to record with high fidelity.

The Sound Intensity Method is used for the measurement of sound intensity and power of sources. Measurements are made with the frequency domain method that allows the use of sound pressure, sound intensity, phase, and coherence spectra to evaluate how accurate the data are. Unless a person is very proficient and properly trained, results can be in substantial error and lead to false conclusions. The use of these spectra can help determine how trustworthy the results are.

Sound Noise and Vibration Measurement and Testing Services Offered:

Sound and vibration measurement and testing services include:

- Sound Intensity Measurements
- Sound Power Measurements
- Plant Noise Surveys
- Noise Contours and Mapping
- Occupational Noise Exposure Measurements
- Community Noise Surveys
- Room NC & RC Measurements
- HVAC RC Measurements
- ASTM Pipe Lagging Standards Testing
- In-Situ STC and FSTC Field Transmission Loss Testing
- FIIC Impact Testing of Floor-Ceiling Assemblies
- Precision Reverberation Time Measurement
- In-Situ Absorption Measurement
- Pipe Lagging Transmission Loss Measurement
- ANSI, ISO, & ASTM Standards Testing
- Rotating Equipment Measurements
- Structureborne Noise and Vibrations
- Ground Vibrations
- MRI & CT Scanner Site Measurements
- Transmissibility Testing
- Validation of Vibration Isolation of Equipment
- Modal Analysis for Noise & Vibration Control
- FSTC and FIIC testing
- Community noise level measurements and studies
- Noise contouring of industrial plants
- Sound intensity measurements of noise sources for ranking and control
- Absorption coefficient measurement

Sound Noise & Vibration Measurements and Testing Projects Completed:

Over 1000 projects have been successfully completed by Thornton Acoustics & Vibrations that includes the measurement and testing of:

- Paper lines
- Aircraft jet engines
- Corporate jets
- Military weapons
- Machine guns
- MRI noise
- MRI site vibrations
- CT Scanner site vibrations
- Refinery equipment
- Haul trucks
- Emergency generators
- Fans
- Engines
- Motors
- Refinery sound power measurements
- Sound intensity measurements of submarine components
- River dredging operations
- Compressor stations
- Machine shops
- Corporate jet aircraft engine noise
- Police gun ranges
- Air raid siren
- Highways and interstates
- Hospital helicopter operations
- Drag strips
- Airports
- Fossil fuel power plants
- Nuclear power plants
- Trucking terminals
- Outdoor and indoor HVAC
- Chemical plants
- Printing plants
- Gunshot murder cases
- Ski resort compressors
- Steel plants
- Scrap yards
- Mining operations
- Landfill operations
- Nightclubs
- Electric arc furnaces
- Asphalt and paving plants
- Casting shake out
- Go cart tracks
- Pipe mills
- Concrete and asphalt kilns
- Wood chippers
- Refrigeration equipment for ice rinks
- Amusement parks
- Coal prep plants
- Yucca Mountain nuclear waste site
- Bin sorter
- RTO’s
- Air knife
- Mine fans