Sound Insulation Testing

Sound Test
Reverberation Time

Building Compliance Testing Limited can provide you with a fast and cost effective SITMA Accredited Pre-Completion Sound Insulation Testing across Mainland UK, in accordance with BS EN ISO140 and BS EN ISO16283.

green tick BCTSound Insulation Testing – Reverberation Time

also known as acoustic testing, or pre-completion testing, testing must be carried out on new build properties as well as converted properties to demonstrate compliance with Approved Document E. A property will either require an Airborne test or an Airborne and Impact test. Airborne tests are carried out on separating walls and floors between habitable rooms of flats and houses which consists of placing a loudspeaker in one room for a steady source of noise. Several measurements are taken around the speaker. Measurements are then taken on the other side of the wall or floor. Impact tests are carried out on the separating floors between habitable rooms of flats and consist of a tapping machine is placed on the floor and measurements are taken in the room beneath. The tapping machine is placed on in 4 random location within the source room. Please ensure carpet is removed for this part of the test and access available to both sides of the floor.

Typically each test takes between ten to twenty minutes to complete. This all depends of the size of the building, the test locations, the ability to create stable sound field and unfortunately the uncontrollable influence of environmental noise.

Reverberation Time:

Reverberation time (RT60) is a measure of the time it takes for sound to decay in a closed space after the sound source has stopped emitting sound. It is typically expressed in seconds and is an essential parameter in room acoustics. A shorter RT60 indicates that sound decays quickly, while a longer RT60 implies a more prolonged sound decay, which can impact the quality and clarity of sound in a space. Controlling and optimizing RT60 is crucial in various settings, including concert halls, recording studios, auditoriums, and other acoustic environments, to achieve the desired acoustic properties and avoid issues like excessive reverberation or a “dead” sound.

Reverberation time (RT60) does not directly impact the results of a sound insulation test, which typically measures the sound transmission through walls or floors between rooms. The primary purpose of a sound insulation test is to assess the effectiveness of building elements in blocking airborne and impact sound transmission.

Reverberation time is more relevant in the context of room acoustics and the quality of sound within a space, such as concert halls or auditoriums. It pertains to the time it takes for sound to decay in a room after the sound source has ceased emitting sound. In this context, controlling reverberation time is essential to optimize the acoustic properties of a space, ensuring good sound quality and clarity.

In sound insulation tests, the focus is on evaluating the sound transmission characteristics of building partitions (e.g., walls or floors). These tests measure the ability of these structures to block sound transmission and prevent it from traveling between adjacent spaces. The results are typically presented in terms of sound insulation performance, sound reduction indices, or other relevant metrics that assess the effectiveness of the building elements in attenuating sound.

So, while reverberation time is crucial for room acoustics and the quality of sound within a space, it is not a factor in the results of sound insulation tests, which primarily concern sound transmission through building partitions.

A sound test for reverberation time is an acoustic measurement used to evaluate the acoustic properties of a room or enclosed space. Specifically, it assesses how long sound persists or reverberates within the room after an initial sound source is stopped. The measurement is crucial for understanding the acoustic characteristics of a space and is often used in architectural design, construction, and acoustic engineering.

Key aspects of a sound test for reverberation time include:

  1. Test Setup: The test is typically conducted in a room with specific dimensions and characteristics. It is essential that the room’s acoustic conditions are well-controlled, including factors like room size, shape, surface materials, and sound-absorbing elements.

  2. Sound Generation: A brief and loud sound source, such as a gunshot, clap, or a controlled sound burst, is used to introduce sound energy into the room. The choice of sound source may vary depending on the specific testing requirements.

  3. Measurement: Highly sensitive microphones and sound measurement equipment are strategically placed within the room. These instruments record the sound level as it decays or diminishes over time after the initial sound source has stopped.

  4. Analysis: The data collected is then analyzed to determine the reverberation time, which is the time it takes for the sound in the room to decrease by 60 decibels (dB) from its peak level. The measurement is typically performed at multiple frequencies, as different frequencies of sound may have different decay times.

Reverberation time is an important parameter for various applications, including:

  • Concert Halls: Longer reverberation times may enhance the acoustic experience, providing a sense of spaciousness and richness in sound.

  • Classrooms: Shorter reverberation times are often preferred to improve speech intelligibility and reduce acoustic distractions.

  • Recording Studios: Controlling reverberation time is critical for achieving desired sound recording and mixing conditions.

  • Open Office Spaces: Balancing reverberation times can help manage noise and acoustic comfort in office environments.

  • Auditoriums: Tailoring reverberation times is essential to create optimal conditions for music and spoken word presentations.

Reverberation time tests are valuable for architects, acoustic engineers, and designers in ensuring that a room’s acoustic characteristics align with its intended purpose, whether it involves creating a lively concert hall, a quiet workspace, or any other acoustic environment.


The Standards

During Sound Insulation Testing, we adhere to British Standards that define the testing and rating of sound insulation for both Airborne and Impact Sound Insulation. These standards include:

  1. BS EN ISO 140-4 – This standard covers the measurement of airborne sound insulation between rooms, providing guidelines for field measurements.

  2. BS EN ISO 140-7 – It addresses the field measurements of impact sound insulation of floors, ensuring comprehensive testing.

  3. BS EN ISO 717-1 – This standard is all about rating airborne sound insulation, offering a framework for assessing and comparing sound insulation in building elements.

  4. BS EN ISO 717-2 – Similarly, it focuses on rating sound insulation, but for impact sound, enabling a thorough evaluation.

Building Regulations Approved Document E encompasses four key areas:

  • E1 – Protection against sound transmission from other parts of the building and adjoining structures.
  • E2 – Protection against sound transmission within a dwelling-house and similar areas.
  • E3 – Addressing reverberation in common internal parts of residential buildings, such as flats.
  • E4 – Ensuring appropriate acoustic conditions in educational facilities.

Part E of the Building Regulations sets forth guidelines for achieving reasonable standards of sound insulation in residential buildings across England and Wales. It applies to a wide range of spaces, from homes to hotels, and covers new constructions as well as those undergoing refurbishment or conversion from a different use.

The objective of Approved Document Part E is to enhance occupant comfort and well-being by minimizing noise transmission, both airborne and impact, between neighboring homes and within internal spaces. Compliance with Part E necessitates the use of sound insulation systems that meet the required airborne and impact noise insulation levels, often accomplished using Robust Details.

For internal walls, a minimum airborne sound insulation level of Rw 40 dB (laboratory test results) is required. This applies to internal walls between bedrooms and other rooms, as well as between bathrooms and other rooms, excluding internal walls with doors. Internal floors must also meet a minimum airborne sound insulation level of Rw 40 dB.

Separating floors between new homes and purpose-built residential spaces must achieve a minimum airborne sound insulation level of 45 dB DnT,w + Ctr (or 56 dB DnT,w in Scotland), which is determined through on-site testing and differs from internal walls. For rooms resulting from a change of use or conversion, the minimum requirement is 43 dB DnT,w + Ctr (or 53 dB DnT,w in Scotland).

In terms of impact sound transmission, the maximum allowable level is LnTw 62 dB (or LnTw 56 dB in Scotland) for separating floors between new homes and purpose-built residential spaces. For rooms converted from a change of use, the maximum limit is LnTw 64 dB (or LnTw 58 dB in Scotland).

These standards and regulations ensure that sound insulation in residential buildings meets specified performance criteria, contributing to a more peaceful and comfortable living environment.


The Equipment

It’s no surprise that the equipment used for Sound Insulation Testing is exceptionally specialized and necessitates frequent, precise calibration for consistent accuracy. All of our measurement equipment adheres to the strict requirements of accuracy class 0 or 1 as outlined in IEC 60651 and IEC 60804. Before each measurement, the entire measurement system, including the microphone, undergoes adjustment using a sound calibrator. To uphold accuracy during field tests, all equipment employed by Building Compliance Testing is meticulously calibrated by a UKAS-approved laboratory. It’s important to note that Building Compliance Testing is a registered member of SITMA, ensuring our commitment to upholding industry standards and accuracy in sound insulation testing.

 Whether your requirements is for a domestic retrofit, residential or commercial development, Building Compliance Testing can support you from concept to completion by offering a one-stop-service service:

design reviews – site inspections – pretesting – intensity testing – site management training and education 

Other Services

We can also offer a variety of other specialist services through our Partners, including:

– Full Design Reviews and Specifications

– BB93 Acoustic Design of Schools

– BREEAM Internal Ambient Noise Limit (IANL) Measurements 

-Reverberation Time (RT60) Measurements


Sound Insulation Testing, also known as acoustic or pre-completion testing, is a crucial requirement for both new build and converted properties to demonstrate compliance with Approved Document E. These tests, either Airborne or a combination of Airborne and Impact, assess the sound insulation between habitable rooms. Airborne tests evaluate sound transmission through separating walls, while Impact tests focus on separating floors. Reverberation time (RT60) and background noise measurements, although essential in other contexts, are not factors affecting sound insulation test results. British Standards, such as BS EN ISO 140-4, BS EN ISO 140-7, BS EN ISO 717-1, and BS EN ISO 717-2, guide these tests, ensuring a controlled and standardized process to meet Building Regulations requirements. Building Compliance Testing employs specialized and precisely calibrated equipment to guarantee accuracy and compliance with industry standards throughout the testing process. Whether for domestic retrofit, residential, or commercial development, Building Compliance Testing provides comprehensive support from design reviews to site management, ensuring sound insulation standards are met from concept to completion.


Frequently Asked Questions

How do I prepare for a Sound Insulation Test?
  • Ensure 240v mains electrical outlet is available in all rooms to be tested.
  • Access to site is safe and to all the rooms throughout the building. If the adjacent dwelling is under
    different ownership it is your responsibility to ensure access is available for the testing.
  • All rooms where testing is to occur is vacated of all trades during the sound test.
  • All site staff are made aware of the sound test and the requirement to keep background noise to a
  • Any noisy building work in the vicinity of the sound testing will need to be stopped. This can be ground
    works, cleaning, paining, radios or beeping smoke alarms.
  • Ventilation extractor systems are to be turned off during the sound test.
  • For the impact test carpets are removed.
    The rooms in both sides of the separating element is ≥ 25 m3.
  • A set of sound test consists of two airborne wall tests, two airborne floor tests and two impact tests. This
    applies where the same construction in the walls and floors are used throughout the building. If different
    construction is used, then more sound tests will be required.

We’re friendly and knowledgeable bunch so why not get in touch for a chat. You can always contact Building Compliance Testing with any questions through phone, email or our online chat service.

Don’t worry, we don’t charge for advice given over the phone, so why not ask for a free quote?

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