Material testing for determination of sound insulation performance of acoustic enclosures – Laboratory measurements

Test method for Determination of sound insulation performance of enclosures – Measurements under laboratory conditions helps to determine the sound insulation performance of enclosures; meeting the needs of customers who need to announce results on materials and products that are eligible for installation, use, construction, etc. in works and projects in a convenient, transparent, and compliant manner.

Overview of the test method content Determination of sound insulation performance of enclosures – Measurements under laboratory conditions

Test method name: Acoustics – Determination of sound insulation performances of enclosures. Part 1: Measurements under laboratory conditions (for declaration purposes)

Test method:

ISO 11546-1:1995: Acoustics – Determination of sound insulation performances of enclosures – Part 1: Measurements under laboratory conditions (for declaration purposes) [1]

Performed at: Laboratory, Institute of Development & Application of Acoustic Materials (DASM).

1. Objectives and test subjects

– Test objective

This standard specifies the in-situ measurement method to determine the sound insulation performance (sound reduction) of enclosures.

This standard does not apply to individual parts constituting the enclosure but only to the entire enclosure.

1. The sound insulation of the parts constituting the enclosure such as walls, doors, windows, silencers, etc. must be measured in accordance with other relevant standards.
2. Standards related to the measurement of noise reduction of enclosures under laboratory conditions (TCVN 7839-1 (ISO 11546-1) and in cabins (ISO 11957).

The measurement methods specified in this standard are based on ISO 3740, ISO 9614, and ISO 11200 (see Table 1).

Depending on the selected method, the sound insulation performance (sound reduction) of the enclosure is determined by the reduction of sound power level or sound pressure level.

This method is intended to be measured at the position where the enclosure surrounds the actual sound source (machine). When these methods cannot be implemented, alternative methods such as using an artificial sound source can be used. These methods are also described in this standard.

– Test subject

The entire enclosure.

– Selection of measurement method

The sound insulation performance value of an enclosure can only be accurately measured by measurements using an enclosure designed for the actual sound source. Therefore, if possible, measurements should be carried out using the actual sound source method. If the enclosure is fixed or attached to another sound source, the sound insulation performance can only be determined using the actual sound source. If the actual sound source cannot be used, the substitution method using the sound field outside can be used to determine the sound insulation performance. In cases where neither the actual sound source method nor the substitution method can be used, the sound insulation performance can be measured using an artificial sound source inside the enclosure as described in Appendix A. (For enclosures that can be commonly used using sound absorption materials on the inner surface and a small gap ratio (preferably <2%), this method is particularly useful. The substitution method and the artificial sound source method can be applied to enclosures with a volume smaller than 2m³.

Enclosures with a gap ratio deviating significantly from the standard on gap ratio and sound absorption standards must be measured using the actual sound source. The substitution method and the artificial sound source method cannot be applied to close-fitting enclosures (enveloping and coating) because there is no free volume between the enclosure and the surface of the actual sound source. In cases where a single-number quantity is required based on measurements conducted by the substitution method or the artificial sound source method, the A-weighted sound pressure insulation, Dpr.w, and the A-weighted sound power insulation, DW.w, are used (See definitions 3.13 and 3.14). The weighted sound insulation is a single-number value that can be used to roughly compare different types of enclosures. However, this quantity should not be used as a general measurement for the sound insulation performance of the enclosure because the actual sound insulation performance depends heavily on the actual noise spectrum. If the actual noise level is known or assumed, the A-weighted noise level reduction due to the use of the enclosure can be estimated according to the method given in Appendix C. NOTE 7. Measurement data using an actual sound source do not necessarily have to be compared with measurement data using the substitution method or the artificial sound source method. In cases where the actual sound source is attached to the enclosure, structural-borne sound transmission may affect the measurement results.

– Test method applied to enclosures without an actual sound source

+ Substitution method

+ Artificial sound source method

2. Experimental procedure

Implementation steps:

• Preparation, arrangement of equipment, microphones, etc.
• Performing the test.
• Processing and reporting results.

3. Notes on Measurement Uncertainty

When using measurement methods employing actual or artificial sound sources in accordance with this standard, a standard deviation equal to or lower than that of the international standard used will occur.

For the substitution method, the standard deviation in the frequency range from 250Hz to 10,000Hz is close to the standard deviation specified in ISO 3741. At the frequency range from 50Hz to 250Hz, the measurement uncertainty of the supplementary measurement must be close to the desired standard deviation.

If a measured result value is declared, it must be certified in accordance with ISO 4871.

Role – and importance of the test method Determination of sound insulation performance of enclosures – Measurements under laboratory conditions

The test method Determination of sound insulation performance of enclosures – Measurements under laboratory conditions performed by the Institute of Development & Application of Acoustic Materials helps meet all practical needs of customers and businesses wishing to:

• Determine the sound insulation performance (sound reduction) of enclosures.
• Control quality during the production process, optimize research and development of enclosures.
• Publishing test results to increase competitiveness and sales, or to bring materials and products into installation, use, and construction in projects smoothly, transparently, and compliantly.

In addition, in cases where the test sample does not meet standards, DASM will conduct consulting and design of shapes, structures, and materials to optimize the design efficiently and cost-effectively.

If previously you had concerns and had to spend heavily on similar activities abroad, now you just need to contact DASM. The entire remaining process will be proactively handled by us as a comprehensive package in the shortest time to complete your customer experience with us: DASM provides acoustic consulting services with truly superior quality, highly competitive pricing in the industry, and dedicated, attentive customer care policies.

The significance of acoustic material testing services at DASM

Today's globalized commercial life opens up countless new markets and sources of supply across five continents. Accompanied by international regulations and standards, this helps customers easily evaluate and trace product origins, and select suitable or superior items. In particular, they support manufacturers in continuously improving and perfecting technology, techniques, raw materials, production methods, and sales, etc.

The DASM Institute is a pioneering, comprehensive, professional, and leading reputable brand in Vietnam in the field of acoustics. On January 12, 2023, DASM was granted registration certificate number 114/TĐC - HCHQ by the Directorate for Standards, Metrology and Quality (Ministry of Science and Technology), certifying the registration of multidisciplinary testing activities in the field of Mechanical-Physical (registration number: 707/TN - TĐC).

Our acoustic material testing services provide customers with practical professional results to meet sustainability, standard performance, and optimized design solutions, consulting, and calibration for products and services. From there, you will update, meet, and adapt to constantly changing international standards to achieve breakthroughs in revenue and profit and elevate your brand.

At the same time, they promote the optimization of production and product marketing processes quickly and economically; contributing to improving value, expanding the market, and spreading the competitive advantages of the enterprise's products and services in Vietnam, the region, and internationally.

If you have a need to perform Material testing Determination of sound insulation efficiency of acoustic enclosures – Measurement in laboratory conditions please contact via Hotline for detailed consultation!