Quantifying the effect of flanking sound transmission on sound insulation and speech privacy metrics

Abstract

In modern commercial office design, sustainable building codes and quality standards often demand certain levels of sound insulation to ensure sufficient speech privacy or freedom from distraction for the occupants. Missing from the minimum requirements of these documents, however, is guidance on eliminating flanking weaknesses that repeatedly and significantly degrade the experienced speech privacy. This paper presents case studies of common acoustical weaknesses found between closed offices and meeting rooms. Through the use of sound intensity measurements and acoustical imagery, the sound power of each weakness is calculated and shown relative to the sound power of the separating partition. By comparing these results to partitions without these weaknesses, the effective reduction in speech privacy is demonstrated using the ASTC, NIC, and SPC metrics. Weaknesses examined and ranked include, open ceiling plenums, lack of or ineffective door seals, door closure pressure, continuous door frames, façade mullions and transoms, interior windows and their frames, lack of acoustical sealant, uninterrupted gypsum on side walls, common door frames at the edges of partitions, modular and operable walls and their junctions, continuous heating elements, thin continuous floor toppings, and ventilation duct crosstalk.