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4.2 Acoustics and Vibrations Laboratory


Acoustics and vibrations laboratory is in process of acreditation by quality organizations for an exceptional endowment, in equipments and work areas. In this field the acoustic team can realize noise and vibration measurements, complex analysis and post-processing and also noise mapping according to 49/EC/2002 Directive.

Equipment endowing the laboratory, is high end, made by Bruel&Kjaer and 01dB Metravib, covering entire measuring-testing range required by Romanian standards and European Commission Norms.

Specialized rooms for measuring-testing, anechoic, reverberant and trap room are made as house within house offering enough protection against exterior noise and vibrations.

The anechoic room was designed and executed according to ISO 3745 requirements.


· Anechoic room volume is 1200 m3 with 15x10x8 m
· Wall's absorption coefficient is ³ 99% in frequency range of 150 Hz up to 20 000 Hz.
· Distance field irregularity variation:
   L=phonic pressure level;    
   d=distance from sound source to measuring point
· L±0,5 dB for d< 2 m
· L± 1 dB for d=3 m
· L± 1,5 dB for d=4 m
· L± 2 dB for d=5 m
· L± 3 dB for d=7,5

· Background noise is within Cz 25 noise curve
· There can be measured noise source with a maximum volume of 6 m3.
· Wide access door (3,5 x3 m).


Was executed according to ISO 3741- Annex D and ISO 354 requirements.


· Volume: 202,4 m 3 with average sizes of 4,7x5,9x7,3 m
· Background noise is within Cz 25 noise curve
· Frequency range for measuring, determined by room volume:
o lowest frequency in lowest band of 1 octave - 125 Hz
o lowest frequency in band of 1/3 octave - 100 Hz
· There can be measured noise source with a maximum volume of 2 m3 (smaller than 1% of room volume).

Trap room is made of:

1. In diffusion field measuring bench for phonic insulation of air noise, made of horizontally juxtaposed reverberant rooms of which a transmitting one and a receiving one, each of a volume of 106 m3 and average sizes of 3,7x4x6,1m. Between these rooms there is a 10 m2 window for placement of parts to be tested.
2. Impact noise insulation measuring bench made of vertically juxtaposed rooms of which a transmitting one placed above and a receiving one placed below, with an 10 m2 horizontal window for placing parts to be tested.
Acoustic transmissibility through boards block was made according to ISO 140/1, /7, /8, STAS 6161/4 and STAS 6691 international and Romanian standards.

Service range (according to current standards)

  • · Measurements and recordings;
    · Noise-signal analysis;
    · Noise measurements for industrial installations (machines and aggregates);
    · Urban traffic noise measurement;
    · Airport noise measurement;
    · Noise maps realization;
    · Structural acoustic characteristic determination;
    · Destructive acoustics;
    · Audition halls quality;
    · Transitory noise measurement (pressure jumps, sonic boom, ammunition firing);
    · Phonic power determination (ISO 3740 - ISO 3747);
    · Conversation clarity and quality determination;
    · Hydro acoustic measurements;
    · Ultrasonic measurements;
    · Industrial noise attenuation (purging air/steam attenuators, made by COMOTI , machines and aggregates casings);
    · Decrease of industrial and civilian noise (building and areas phonic insulation);
    · Means of transportations noise reduction;
    · Vibrations signal analysis;
    · Vibration mechanics testing;
    · Aggregates condition diagnosis;
    · In frequency response of vibration translators;
    · Vibrations dumping down for industrial machines and equipments;
    · Transportation vehicles vibration dumping.

Laboratory capability regarding acoustic an vibration domain

1. Measurements - in acoustic domain

  • · Measurements and recordings; 
    · Frequency range: from 0,1 Hz to 140 kHz;
    · Dynamic domain: from 10 dB to 170 dB;
    · Noise - signal analysis;
    · Frequency band: 1 octave, 1/3 octave, 3%, 23%,  constant band (3,16 Hz, 10 Hz, 31,6 Hz, 100Hz), narrow band 0,25% (0 - 20 kHz);
    · Frequency domain: from 0,2 Hz to 160 kHz;
    · cestrum ;
    · Regulating conditions control;
    · Industrial installations noise measurement (machines and aggregates);
    · Urban traffic noise measurements;
    · Airport noise measurements;
    · Structural acoustic characteristic determination;
    · Absorption coefficient;
    · Acoustic radiation;
    · Air noise insulation capability;
    · Impact noise insulation capability;
    · Destructive acoustics;
    · Phonic resistance (structure and equipment exposure to 135 dB);
    · Functional tests;
    · Pressure jumps measurement by ammunition firing;
    · Audition halls quality;
    · Reverberation span measurement;
    · Transitory noise measurement (pressure jumps, sonic boom, munition firing);
    · Phonic power determination (ISO 3740 - ISO 3747);
    · Conversation clarity and quality determination;
    · Hydro acoustic measurements;
    Ultrasonic measurements;

2. Reference material

· Industrial noise dumping ( purging air/steam attenuators, made by COMOTI , machines and aggregates casings);
· Decrease of industrial and civilian noise (building and areas phonic insulation);
· Means of transportations noise reduction;

3. Vibrations domain testing-measurement

· Measurements and recordings;
· Frequency range : from 1 Hz to 60 000 Hz
· Dynamic domain : from 0 to 5 000 g
· Vibration signal analysis;
· frequency band : 1 octave, 1/3 octave (2 Hz -160 kHz); constant percentage 3%, 23% (0 - 20 kHz); narrow band 0,25% (0 - 20 kHz);
· Dynamic domain: 0 - 5 000 g;
· Vibration mechanics testing;
· Frequency domain: from 5 Hz to 5 000 Hz;
· Maximum load: 50 kg;
· Aggregates condition diagnosis;
· In frequency response of vibration translators;
· Maximum mass: 300 gr;
· Frequency domain : from 5Hz to 2 000 Hz;
· Maximum acceleration: 115 m/s2.

4. Reference material

· Industrial machines and equipments vibrations dumping;
· Transportation vehicles vibrations dumping.


1. Jet engine's noise reduction by using a secondary air flux.
2. Phonic endurance testing of IAR - 93 airplane's air scoops.
3. Noise measuring on airfield during take off - landing.
4. Noise and vibration pressure level determination in VIP cabin for airplanes and helicopters.
5. Absorption coefficient for materials used to increase acoustic comfort inside airships.
6. Industrial noise dumpers for free purges in thermal power plants:
o Jet silencers    SILENCE - COANDA
o Jet silencers   T 20 ÷ T 260
o Jet silencers   AZ  20 – 60 – CONEL - Bacău
o Anti-pumping valve jet silencer ASAP 21-00 - Suplacu de Barcău
o Dumpers for testing bench
o AZ 17 – 00 - Adjud
7. Noise dumpers for ST 18 Pratt & Whitney and AI-20 turbine engines including:
· Ventilated phonic insulating cell with noise dumpers for ventilated air entry and exit equipped with scoop doors closing systems in case of fire.
· Engine air aspiration noise dumper.
· Engine exhaust gas exit dumper.

8. Noise reduction on own turbine engine testing bench

· Engine air admission noise dumper
· Engine gas exhaust noise dumper

9. Noise reduction studies for various clients (SIDEX Galaţi, Porţile de Fier II, and others)
10. Acoustic measurement on Henri Coanda Airport for CFM-56 turbine engine equippingBoeing 737.

INCDT-COMOTI Acoustics and Vibrations Laboratory is endowed with portable analyzers such as Bruel & Kjaer 2250 model and 2260 model and 01dB-Metravib SOLO Master and Premium, 01dB-Metravib and Bruel & Kjaer multi chanel acquisition systems: part of the IVth innovating generation of acoustics and vibrations equipment.

2250 Platform contain:

· Internal software modules set, including frequency analysis and sound and signal recording (logging) in order to play it back;
· Separated modules, easy to be activated through license keys or by ordering exactly what you want directly to the factory.

2250 Platform has following uses:

· Surrounding noise evaluation and monitoring;
· Work environment noise evaluation;
· Phonic protection selection;
· Production quality control;
· Class 1 sound measurement, according to international standards;
· Frequency analysis in band of 1 octave and 1/3 octave;
· On time signal analysis and broadband parameter analysis with recording;
· Measurements logging using text and vocal inputs;
· Measurements logging by sound recording in order to play it back;
· An embedded microphone which allows vocal remarks attached to the measurements for an easier documentation and recalling of during measurement events.

2250 Platform has following characteristics:

· Indicates measurements and states using "semaphore" type indicators;
· Large size, high definition color touch screen;
· High capacity rechargeable battery sets Li-Ion;
· Data logging on standard plug-in memory cards Secure Digital and Compact Flash;
· Standard USB PC interface (On-the-Go);
· Dynamic domain over 120 dB;
· Linear frequency domain 3 Hz - 20 kHz
· Real time frequency analysis in bands of 1/1 or 1/3 octave (optional module)
· Sound recording during measurement;
· Broadband or spectral band values can be recorded (logging) for long term in order to later analysis (optional module);
· Ability to automatic configure and detect the protective screen;
· Connectivity - standard, high speed interfaces;
· IP44 protection level.


2260 Platform:

1. Two channels allowing use of intensity sounder
2. Variety of internal and PC software to provide results and solution over a large scale of noise and sounds related problems.
1. Completely programmable through cards;
2. PCMCIA interface for various applications;
3. High logging capacity for measured data;
4. Besides broadband and 1 octave real time measurements, it can analyze room's and building's acoustics (1-2 channels), acoustic intensity and notes detection



01dB-Metravib SOLO Master and Premium platforms:

· According to most recent international standards (IEC 61672-1) regarding noise levels measurement;
· Can make vibration and vehicle noise measurement, sound and vibration monitoring, real time analysis of 1/1 and 1/3 octaves frequency;
· 24-bit analog-digital conversion which allows one dynamic scale (117 dB) measurement, and it's high memory allows simultaneously measured data logging;
· USB makes SOLO a real time analyzing, PC connected device;

  • Using a modem or a GSM terminal, SOLO can be monitored from a distance and can be asked to extract all measured data, without interrupting current measuring session.

Sony EX-IF10D Orchestra Unit 01dB-Metravib

Technology that can be endowed with 6 IEPE/Direct modules each of 4 channels, meaning it can acquire 24 channels; these EX-IF10D units can be connected and configured for much more complex acquisitions of up to 192 channels (acquired signals can be acoustic, vibrations or combination of both to aid synchronizing).

We mention that this equipment is part of INCDT-COMOTI Acoustics and Vibrations Laboratory's equipment.

PULSE™, BK multi analyzer 3560 C type, versatile analysis system, oriented for applications that represents a platform for a large variety of Brüel & Kjær applications of PC assisted measurement.

PULSE™, BK multi analyzer 3560 C type

A PULSE system consists of a computer with (LAN) networking interface computer, PULSE Labshop, Microsoft ® Windows NT ® , Windows ® 2000 or Windows ® XP, Microsoft ® Office licensed software, and an 3560 B, C D or E acquisition unit.


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