The Forensic expert kollegium conducts measurements and determination of the insulation of the normalized impact sound level by internal building enclosures under field conditions.

Impact sound measurement involves on-site measurements of the sound insulation performance of inter-floor slabs and internal walls, which are regulated only for living rooms (no standards are established for such premises as kitchens, corridors, and bathrooms).

The regulated indicator of impact noise is the normalized impact sound level index, which is measured in relation to:

• inter-floor slabs between two living rooms (where the slab serves as the ceiling of one room and the floor of another room);
• internal walls between a living room and a stairwell.

Violations of flooring installation technology frequently occur during the laying/installation of floor coverings, resulting in changes to the impact sound insulation index. In such cases, occupants of the lower residential unit are affected, as their comfortable use of the apartment is disrupted by increased noise levels caused by walking, moving furniture, etc.

When examining the insulation of the normalized impact sound level of an inter-floor slab, the center of each living room in both the upper and lower premises must be free of furniture. In addition, carpets must be removed from the floor of the upper room.

When examining the insulation of the normalized impact sound level of internal walls, any wall carpets on the living room side must be removed, and access must be provided for the placement of sound-measuring equipment at a distance of at least 2 meters from the wall. Noise generated by construction tools and other high sound power sources during measurements of normalized impact sound level insulation is not permitted.

A special tapping machine is used to determine the insulation of the normalized impact sound level by building enclosures. This tapping machine applies impacts to the floor covering using hammers operating at a standardized frequency and impact force, while sound-recording equipment with microphones (a sound level meter) is installed in the living room under examination to register the extent to which the floor slab attenuates the impact.

Before each series of measurements, all sound-measuring equipment undergoes calibration. All measuring instruments of the Forensic expert kollegium used for acoustic measurements are included in the State Register of Measuring Instruments of the Republic of Belarus and have undergone the required state verification in accredited laboratories of the State Standardization Committee of the Republic of Belarus.

The principal question answered by a study conducted by the Forensic expert kollegium to determine the normalized impact sound level is: “Does the insulation of the normalized impact sound level provided by building enclosures comply with the requirements of the technical regulatory legal acts in force within the territory of the Republic of Belarus?”

Other causes of inadequate sound insulation performance of building enclosures may include:

• errors made during the design of residential premises;
• use of construction materials that do not comply with the design specifications;
• violations of floor covering installation technology.

Based on the measurement results, a specific numerical value (index) characterizing the sound insulation performance of the floor slab is determined. The obtained value makes it possible to assess the feasibility of implementing measures to improve the sound insulation of the premises, as well as to determine which engineering solution may be applied to achieve acoustic comfort.

If necessary, specialists of the Forensic expert kollegium can also perform acoustic calculations of the sound insulation performance of building enclosure structures.

You may contact the Forensic expert kollegium for consultation regarding measurements and determination of the insulation of the normalized impact sound level by internal building enclosures at: Minsk, Zhukovskaga St., 11A, 4th floor

or by phone: +375 (17) 317 04 71; +375 (17) 317 04 72; +375 (17) 317 04 73; +375 (17) 317 04 74; +375 (17) 317 04 76; +375 (29) 109 60 11; +375 (44) 588 60 11.