This specification covers cast sound-signalling bells, together with bulkhead mounting plates for the smaller bells, for use on ships, boats, and other marine craft, for compliance with the rules in the convention on the International Regulations for Preventing Collisions at Sea. Bell bodies, clappers, and other cast fittings and parts shall be copper alloy. Fittings such as bolts, nuts, washers, pins, and supporting lugs shall be of copper alloy compatible with the bell castings. Bells shall have full, clear, round, and farreaching tones. The sound pressure level shall not be less than 110 dB at a distance of 1 m from it. Acoustic tests shall be conducted only for the 200 mm heavy and larger bells to check the requirements prescribed.

1.1 This specification covers cast sound-signalling bells, together with bulkhead mounting plates for the smaller bells, for use on ships, boats, and other marine craft, for compliance with the rules in the convention on the International Regulations for Preventing Collisions at Sea (commonly called Colregs).2 See Appendix X1.

1.2 Bells and bulkhead mounting plate shall be sized as indicated in Section 4 (see Appendix X2).

1.3 For consistency with International Regulations, all measurements are in SI units.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.