The Importance of Acoustic Attenuation:
Understanding and Controlling Noise Pollution
Noise is a constant presence in our daily lives. It can be pleasant when it involves music or natural sounds. However, intrusive or disturbing noise can be a source of stress, fatigue, and discomfort—whether at work or at home—when it interferes with concentration, rest, or communication. In both communal living spaces (residential areas, offices, schools, etc.) and sensitive buildings such as hospitals, secure facilities, or public venues, effective sound insulation is essential to ensure the comfort, privacy, and hearing protection of occupants.
Optimized soundproofing helps reduce the transmission of airborne noise, traffic sounds, and impact noise, thereby contributing to a quieter, safer, and more comfortable environment. Thanks to established standards (EN ISO 717-1 for joinery), the acoustic performance of doors, windows, service counters, and partitions can be accurately assessed, allowing tailored solutions for every need.
Sound, frequency, decibels: how do you measure the impact of noise?
Some basic concepts
Acoustics is based on two key parameters:
- Sound frequency, measured in hertz (Hz), which determines whether a sound is low or high
- Sound intensity, measured in decibels (dB), which reflects the perceived volume by the human ear
Sound is an air vibration that travels in waves. The human ear perceives sounds with frequencies between 20 Hz and 20,000 Hz:
- Low frequencies (20 to 200 Hz): low-pitched sounds like thunder or speaker bass
- Mid frequencies (200 to 2,000 Hz): human voice, traffic noise
-
High frequencies (2,000 to 20,000 Hz): high-pitched sounds like a whistle or alarm
Sound intensity is measured in decibels (dB) and follows a logarithmic scale:
- A 3 dB increase doubles the sound intensity
- A 10 dB increase multiplies the sound energy by ten
- Two sounds of the same level do not simply add up: two machines at 60 dB together produce 63 dB, not 120 dB
What is an “acceptable” noise level?
Noise perception is subjective: it depends on the time of day, its regularity, its origin, and the level of control one has over it.
- Involuntary noise is more disturbing than chosen noise
- Unpredictable noise is more stressful than constant noise
- Night-time noise is more disruptive than daytime noise
For example, a normal conversation (50 dB) may be disturbing in a meeting room requiring confidentiality. Conversely, workshop noise at 70 dB may be acceptable if expected and controlled.
Good acoustic insulation can reduce outdoor noise from 80 dB (busy street) to an acceptable indoor level of 40–50 dB.
Download our guide on acoustic protection
DOIC P060 | Acoustic information
DOIC P060 | Acoustic information
Sound levels and their impact on the human ear
20 dB
whispering
the ticking of a watch
Optimal acoustic comfort,
very quiet atmosphere
30 dB
library
forest
Idéal pour le repos et la concentration
40 dB
quiet office
living room
Low-level noise, conducive to work
50 dB
normal conversation
washing machine
pedestrian street
Acceptable in a professional environment
60 dB
busy restaurant
noisy air conditioning
Starts to be perceived as disturbing, may cause auditory fatigue over time
70 dB
urban traffic
vacuum cleaner
Difficulty concentrating, risk of auditory fatigue after prolonged exposure
80 dB
heavy traffic
lawn mower
industrial workshop
Risk of stress and sleep disturbances
90 dB
motorcycle
train
construction site without sound protection
Hearing damage after a few hours of exposure
100 dB
concert
jackhammer
Risk of hearing loss after just a few minutes of exposure
120 dB
airplane taking off
alarm siren
Immediate pain, danger to hearing
140 dB
Formula 1 car
assault rifle
firecracker
Pain threshold, irreversible hearing damage
Standard EN ISO 717-1: measurement of sound reduction performance
The EN ISO 717-1 standard specifies the methods for measuring the sound reduction index Rw in laboratory conditions. It applies to doors, windows, partitions, and glazing, and tests are conducted under controlled conditions to ensure reliable and comparable results between different products.
The Rw index (expressed in dB) indicates the ability of the joinery to reduce the transmission of airborne noise. The higher the index, the better the acoustic insulation performance.
Procedure of official tests according to the reference standard EN ISO 717-1
The tests are conducted in specialized laboratories. Their objective is to measure the difference in sound level between two separate rooms.
- Source room: a chamber where artificial noise is generated.
- Receiver room: an adjacent space where the amount of noise transmitted through the tested door, window, or partition is measured.
A wideband noise is emitted in the source room, covering a frequency spectrum from 50 Hz to 5000 Hz. This includes:
- Low frequencies (50–250 Hz) simulating low-pitched sounds and structural vibrations
- Mid frequencies (250–1000 Hz) simulating human conversation and ambient noise
- High frequencies (1000–5000 Hz) simulating high-pitched sounds and metallic impact noise
Microphones are placed in the receiver room to measure and analyze the sound level transmitted through the joinery. The Rw sound reduction index (in dB) is then calculated based on the difference between the sound levels in the source and receiver rooms.
Controlling noise: a matter of safety and well-being
Acoustic insulation is essential to ensure an optimal living and working environment. Thanks to reference standards such as EN ISO 717-1, it is possible to measure and guarantee a level of sound attenuation that meets both regulatory requirements and user expectations.
Doors, windows, and partitions play a key role in managing noise pollution. A well-designed acoustic joinery system allows for:
- ensuring confidentiality in meeting rooms, government offices, crisis centers, or strategic decision-making spaces to prevent eavesdropping and information leaks
- reducing external noise such as traffic, construction, or industrial activity
- improving indoor comfort in noisy environments such as offices, hospitals, and schools
At Metal Quartz, we design high-performance acoustic joinery tailored to the most demanding environments.
Our acoustic solutions are naturally combined with anti-burglary, bullet-resistant, or fire-resistant features. Our experts support you in selecting the solution best suited to your technical, acoustic, and security requirements.
Factors influencing the acoustic performance of joinery
The acoustic insulation of a door or window depends on several factors that must be combined for optimal performance:
- Type and density of the frame: the denser the material, the better it blocks sound
- Type of infill: solid, glazed, or specific acoustic double glazing
- Quality of sealing joints: reduces sound leakage
- Proper installation: to avoid sound and thermal bridges
