46 CFR § 113.25-12 - Alarm signals.
(a) Each general emergency alarm signal must be an electrically-operated bell, klaxon, or other warning device capable of producing a signal or tone distinct from any other audible signal on the vessel.
(b) Electronic devices used to produce the general emergency alarm signal must meet the requirements of subpart 113.50 of this part.
(1) The minimum sound-pressure levels for the emergency-alarm tone in interior and exterior spaces must be a sound level of not less than 80 dB(A) measured at 10 feet on the axis; and
(2) At least 10 dB(A) measured at 10 feet on the axis, above the background noise level when the vessel is underway in moderate weather unless flashing red lights are used in accordance with 46 CFR 113.25-10(b).
(d) Alarm signals intended for use in sleeping compartments may have a minimum sound level of 75 dB(A) measured 3 feet (1 meter) on axis, and at least 10 dB(A) measured 3 feet (1 meter) on axis, above ambient noise levels with the ship under way in moderate weather.
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