scope:

This standard specifies methods for measuring and reporting the sound produced by sound-making devices installed at fixed locations outdoors for the purpose of warning people of emergencies. The sound making devices to which this standard is applicable include mechanical, electronic, and mechanical/electronic sirens that produces steady, tonal sounds with a nominal fundamental frequency in the range from 300 to 1000 Hz; when installed at a fixed location outdoors in accordance with the manufacturer's recommendations.

PURPOSE AND APPLICABILITY

The purpose of this standard is to provide methods for measuring and reporting certain properties of tonal sounds produced by audible public warning devices when such devices are installed at fixed locations outdoors. Methods are given for the measurement of the C-weighted sound level produced by the device, and for the determination of the one-third octave band containing the fundamental frequency of the warning sound, at a distance of 100 ft (30.5 m) from the device and at the mounted height of the device. A method is also given for measuring the maximum levels of warning sounds at the heads of bystanders on the ground near the source.

The data so obtained and reported can be used to describe, in part, the performance of audible public warning devices; for verifying compliance with performance specifications; for estimating warning sound coverage; and for determining the sound level at bystanders. This Standard should be useful to manufacturers of warning sound sources, to purchasers of such sources, and to designers of public warning systems that rely upon audible outdoor warning sounds. Consistent application of this standard will minimize misunderstandings between suppliers and users regarding warning sound source performance.

Restrictions regarding sound reflecting surfaces in the immediate vicinity of the warning sound source may limit the general applicability of this standard for some specific installations.