dB Acoustics
and
Environmental Services
dB Acoustics and Environmental Services,
13 Cherry Tree Drive, Blackwood, Lanark ML11 9TF, United Kingdom.
Tel: 01555 894877
web: www.dbsound.co.uk
email: info@dbsound.co.uk
Sound insulation can be measured between two adjacent rooms in a building. Some sound travels as direct transmission through the common separating floor or wall and some as indirect (flanking) transmission through the surrounding structure.
The ability of a structure to provide a degree of sound reduction depends on the thickness and weight of materials and on their relative positions to one another and on the capacity of the surrounding structure minimise indirect transmission.
There are two types of sound insulation measurement that can be carried out, airborne sound insulation and iimpact sound insulation.
In a domestic situation. airborne sound is generated by speech, television, radio or a music system and impact sound is generated by footfalls on the upper surface of a floor. After test measurements are collected, single figure sound insulation performance ratings are calculated. The Scottish Building Regulations uses the single figure ratiings DnT,w and L’nT,w as an objective measure of sound insulation performance.
The term DnT,w represents the Weighted Standardized Level Difference in dB and is used to provide a rating value that expresses the degree of airborne sound insulation provided by a separating floor or wall. The higher the DnT,w value, the better the airborne sound insulation. For instance, a DnT,w rating of 43 or less would be subjectively ‘intolerable’ and a rating of 62 dB or more wouild be subjectively ‘excellent’.
The term L'nT,w represents the Weighted Standardized Impact Sound Pressure Level in dB and is used to provide a rating value that expresses the degree of impact sound insulation provided by a separating floor. The lower the L'nT,w value, the better the impact sound insulation. For instance, a rating of 68 dB or more could be classed as subjectively ‘intolerable’ and a rating of 49 dB or less could be classed as subjectively ‘excellent’. Other rating values would progress from ‘intolerable’ to ‘very poor’ to ‘poor’ to ‘reasonable’ to ‘good’ to ‘very good’ and then to ‘excellent’.
Peoples’ subjective response to sound varies and their will be disagreement among occupants concerning the quality of sound insulation that exists in a building.
The term DnT,w represents the Weighted Standardized Level Difference in dB and is used to provide a rating value that expresses the degree of airborne sound insulation provided by a separating floor or wall. The higher the DnT,w value, the better the airborne sound insulation. For instance, a DnT,w rating of 43 or less would be subjectively ‘intolerable’ and a rating of 62 dB or more wouild be subjectively ‘excellent’.
The term L'nT,w represents the Weighted Standardized Impact Sound Pressure Level in dB and is used to provide a rating value that expresses the degree of impact sound insulation provided by a separating floor. The lower the L'nT,w value, the better the impact sound insulation. For instance, a rating of 68 dB or more could be classed as subjectively ‘intolerable’ and a rating of 49 dB or less could be classed as subjectively ‘excellent’. Other rating values would progress from ‘intolerable’ to ‘very poor’ to ‘poor’ to ‘reasonable’ to ‘good’ to ‘very good’ and then to ‘excellent’.
Peoples’ subjective response to sound varies and their will be disagreement among occupants concerning the quality of sound insulation that exists in a building.
Sound Insulation
