Noise Emission Testing to EN ISO 3744

Noise emission testing measures the sound power level of a machine. For equipment used outdoors it is a legal requirement: in the EU, Directive 2000/14/EC sets the rules for noise emission by equipment for use outdoors, and Turkey applies a regulation aligned with it. The measurement methods come from standards, mainly EN ISO 3744 and EN ISO 3746.

For noise emission testing, apply to CE Danışmanı (CE Consultant); we manage the whole process for you.

Why the test is carried out

• To obtain accurate and repeatable noise measurements for different equipment and conditions
• To compare the emission levels of different noise sources objectively
• To check whether the equipment meets the noise limits and marking rules that apply to it
• To protect people and the environment from excessive noise

Equipment covered by the outdoor noise legislation is marked with its guaranteed sound power level, next to the CE marking.

Typical equipment

• Construction and road equipment: excavators, dozers, road rollers, concrete breakers, paver-finishers, cranes and drill rigs
• Garden and landscaping equipment: lawnmowers, hedge trimmers, leaf blowers, chain saws and motor hoes
• Industrial equipment: portable power generators, compressors and welding generators
• Handling equipment: loaders and lift trucks

Whether a specific machine is covered, and whether a noise limit applies or only marking, is assessed product by product.

The standards

EN ISO 3744 and EN ISO 3746 both define:

• The shape of the measurement surface around the source
• The number and positions of the microphones
• The requirements for the test site
• How the equipment is operated during the test
• How the sound power level is calculated from the measured sound pressure levels

EN ISO 3744 gives higher accuracy. EN ISO 3746 is a simpler method with a larger measurement uncertainty.

How the test is carried out

1. The purpose of the measurement and the applicable standard are defined.
2. The sound level meter, microphones and calibrator are selected and prepared.
3. The measurement surface is defined, for example a hemisphere or a rectangular box around the source, and the microphone positions are set.
4. The instruments are calibrated before and after the measurement.
5. The operating conditions of the equipment are fixed, as required by the standard.
6. Wind, temperature and humidity are checked and recorded.
7. Sound pressure levels are measured at each microphone position, with precautions against background noise.
8. The sound power level is calculated and corrections for the environment and reflections are applied.
9. The results are reported and the records are kept.

Who can measure?

Measurements are made by laboratories accredited to EN ISO/IEC 17025. In Turkey, accreditation is given by TÜRKAK (the Turkish Accreditation Agency). The staff must be trained in acoustics, and the instruments must have valid calibration.

What the acoustic report contains

• The measuring instruments used, with their calibration certificates
• The measurement method, the measurement surface, the microphone positions and the operating conditions
• The measured sound pressure levels in dB(A) for each operating mode
• The calculated sound power level
• The environmental conditions during the measurement
• A comparison of the results with the legal requirements
• A statement on whether the equipment complies, and recommended improvements if it does not
• Photographs of the equipment and the test site, and the data tables

The report is part of the technical file of the machine. For the general safety requirements of machines, see machinery CE marking.

How CE Danışmanı helps

• Checking whether your equipment falls under the outdoor noise legislation
• Selecting the measurement standard and planning the test
• Coordinating the measurement with accredited laboratories
• Preparing the technical file, the declaration of conformity and the noise marking