§ 211.206-2 Alternative test data.

(a) In lieu of testing according to § 211.206–1, manufacturers may use the latest available test data obtained according to ANSI STD Z24.22–1957 or ANSI STD S3.19–1974 to determine the mean attenuation and standard deviation for each test frequency and the NRR calculated from those values. Manufacturers whose data is based on the ANSI STD Z24.22–1957 measurement procedure must state in the supporting information required by § 211.204–4 that the mean attenuation and standard deviation values used to calculate the NRR are based on ANSI STD Z24.22–1957.