Article 15.02(5) - Sound pressure level measurement forecastle
For vessels with accommodation in the forecastle and a bow thruster it is also necessary to measure the sound pressure level in the individual rooms of this accommodation. For vessels where the keel was laid before the 2 April 1976 this applies to N.R.C. certification as well extension of certificates after 1.1.2015.
a) There are different understandings about which engines should in the bow thruster room be running while the sound pressure level measurement is carried out.
b) If a new drive for the bow thruster is installed, all of the transitional provisions applicable to the operation of the existing engine lose their validity. Does this also apply to the sound pressure levels that are to be achieved in the forward accommodation or – if no changes were made to the engine room itself, the insulation or the accommodation – does it only apply to the bow thruster room?
c) What is the procedure for special inspections following conversion or certificate extensions after the end of the transition period, if the measurements exceed 60 dB(A) in the cabins and/or 70 dB(A) in the common rooms? Is it necessary to carry out measurements after the end of the transition period on every old vessel and if so, how and what are the consequences?
a) In principle, ESI-II-5 together with DIN ISO 2923: 2003 are applicable. According to point 7.1 in the standard, all auxiliary machinery ..., that is usually or occasionally in use must be running when the measurement is carried out. It is then, however, necessary to calculate the noise impact (i.e. the average equivalent continuous sound pressure level over 24 hours) on the crew in accordance with point 8.1, since the bow thrusters are used intermittently. This, in turn, calls for a generally applicable definition of the duration of the impact, since the degree of use of the bow thrusters can vary a significantly.
b) In any case, it is necessary to perform a sound pressure level measurement if the engine or a bow thruster is replaced if there is accommodation in the forecastle.
c) If the certificate is being extended after having installed a bow thruster for the first time on a vessel to which the transition period according to Article 15.02(6) applies, or the first certificate extensions after the end of the transition period, the sound pressure levels on such vessels must be determined in the usual way. If the sound pressure level measured exceeds the limit of 70 dB(A) in the common rooms and the cabins den, the bow thruster must be removed or the accommodation may no longer be used. If the sound pressure level measured is below the limit of 70 dB(A), but exceeds the limit of 60 dB(A) in the sleeping accommodation, only operating mode A is permitted.
RV/G (12) 16 rev. 1 = JWG (12) 14 rev. 1; RV/G (12)m 59 = JWG (12)m 61, D9; JWG (12)m 91, item 7.2
Joint working group JWG, noise, bow thruster, sound pressure level