This document specifies an engineering method for the measurement of sound pressure levels in rooms from service equipment installed in the building. This document covers specifically measurements of sound from sanitary installations, mechanical ventilation, heating and cooling service equipment, lifts, rubbish chutes, heating devices, blowers, pumps and other auxiliary service equipment, and motor driven car park doors. It can also be applied to measurements of sounds from other types of equipment or activities within the building, e.g. noise from sport facilities or restaurants. The measurement of noise from external sound sources generating air-borne or ground-borne noise in the building are not included in this document. The methods are suitable for rooms with volumes of approximately 300 m3 or less for instance, in dwellings, hotels, schools, offices and hospitals. The methods are not intended for measurements in large auditoria or concert halls.