When used in fresh air intake and exhaust systems, acoustic external shutters not only reduce the noise from the external environment, preventing it from entering the ventilation system, but also dampen the noise generated during discharge, thereby reducing the amount of sound emitted to the outside. The blades and frame are made of specially drawn galvanized steel sheets, and the insulation material is made of rock wool with a density of 70 kg/m3.

The acoustic external shutter consists of a frame, wall-mounted horizontal blades, and acoustic insulation material inside the blades:

• It provides a practical solution for noisy exhaust and fresh air intake systems.
• It is produced from durable acoustic insulation material.
• In addition to sound absorption, it performs the same function as the external shutters, protecting the ventilation system from rain, birds, and pests.

In the acoustic shutter performance monitoring, sound damping from room to room and performance values are measured and observed.

During the observation of tests and evaluations, the standards referenced in this standard are taken into account and evaluated in conjunction with the referenced standards. The standards are listed below:

• NT ACOU 105: 2000-04 Air Terminal Devices Acoustic Transmission Loss
• NT ACOU 095: 1996-05 Transmission Loss, Transfer Function Method in Ducts
• ISO 10140-1: 2010 Acoustics -- Laboratory measurement of sound insulation of building elements - Part 1: Application rules for specific products
• ISO 10140-2:2010 Acoustics -- Laboratory measurement of sound insulation of building elements -- Part 2: Measurement of airborne sound insulation
• ISO 266:1997 Acoustics – Preferred frequencies for measurements
• ASTM E 90-09, Standard Test Method for laboratory Measurement of Airborne sound Transmission Loss of Building Partitions

Test Setup:

To perform one-way sound measurement, a test room should be set up based on ASTM 90 E and ISO 11691 standards.

Once the test room is set up, sound waves should be transferred from the source room to the analysis room, and the shutters should maintain the noise level as specified by the standards.