ISO 23351-1 Class A (DS,A ≥ 30 dB) is the minimum standard for guaranteed speech privacy in a typical open-plan office with 40–50 dB ambient noise. At this level, conversations inside the pod are inaudible to colleagues outside at normal working distances. For environments with higher ambient noise (above 60 dB), DS,A 35 dB — as achieved by HIGHKA pods — provides a 5 dB margin that ensures the WHO/WELL ≤35 dB interior threshold is reliably met. Do not purchase a single person pod that cannot provide an independently verified ISO 23351-1 DS,A certificate.