Internal noise criteria for residential property

Bedrooms night time (23:00 to 07:00) 30dBLAeq
Individual noise events should not exceed 45dB LAMAX (BS 8233. 1999)
Living Rooms day time (07:00 to 23:00) 40dBLAeq
Gardens and Terraces day time*(07:00 to 23:00) 55dBLAeq

*not in town centre or near main roads

The simplest method of assessing the insulation requirement of a façade is to subtract the internal noise level from the free field external level. e.g. measured level 65 dBLAeq Glazing reduction of 35 RTRA Internal level 30 dBLAeq (according to BS 8233: 1999 simple method).

Glazing in residential property: In some cases standard thermal double glazing units will provide sufficient attenuation, other cases will need a thicker unit with specialist glass. If low frequency noise is an issue secondary units in conjunction with single or double glazed units may be required.

Ventilation: Both trickle and rapid ventilation will need to be considered, this may vary from standard trickle vents to fully mechanical powered ventilation. The ventilation must not compromise the attenuation provided by the glazing. The table below, gives an indication as to the glazing and ventilation requirements at various noise levels:

Image depicting glazing and ventilation requirements at various noise levels

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