PROTECTION AGAINST NOISE ON BOARD SHIPS

1. PROTECTIONAGAINSTNOISEON BOARDSHIPS Hideyuki SHURI Tokai University Tripartite 16th October 2010 Tokyo

2. Contents 1 Introduction and Background 2 Proposals for protection against noise on board ships 3 Discussion and action of the Sub-Committee in DE53 4 Japan’s proposals for a revision of the Code 5 Conclusions

3. Introduction and Background • The European Union Member States (27) and the European Commission proposed the development of amendments to SOLAS regulation Ⅱ-1/36 and a revision of the Code on noise levels on board ships at MSC 83 session on October 2007. • MSC approved a new work program item for the Sub-Committee on Ship Design and Equipment (DE), “Protection against noise on board ships”. • “The Sub-Committee on Ship Design and Equipment should consider the possibilities of revising SOLAS regulation Ⅱ-1/36 with the aim of incorporating mandatory noise level limits for machinery spaces, control rooms and workshops based on a revised Code on Noise Levels on Board Ships. The Sub-Committee should further consider the introduction of mandatory regulations to mandate noise level limits in other work and living spaces, where it is found necessary and appropriate.”

4. Proposals for protection against noise on board ships The development of amendments of SOLAS regulation Ⅱ-1/36 to incorporate mandatory noise regulations. A revision of the existing Code on noise levels on board ships, IMO resolution A.468 (Ⅻ).

5. Proposalfor revised text in SOLAS regulation Ⅱ-1/36 in DE53/10 Regulation 36: Protection against noise “Measures shall be taken to reduce the noise on board as far as possible and in any event it shall not exceed the mandatory maximum noise limits and the maximum noise exposure limits stipulated in IMO resolution A.468 (Ⅻ), chapter 4.2 and chapter 5. The actual noise levels shall be assessed on the basis of measurement conditions stipulated in chapter 2 and 3 or equivalent internationally recognised standards.” At noise levels above 85dB(A), ear protection shall be used. At noise levels above 80dB(A), individual hearing protectors will be made available. The regulation should apply to new ships and major conversion ships.

6. Proposalfor amendments of IMO resolution A.468 (Ⅻ) Chapter 4.2 : Maximum noise limits and spaces A 5dB(A) reduction of the maximum noise level to IMO resolution A.468 (Ⅻ) for machinery spaces, workshops, mess rooms, cabins, etc. A new room category and related noise level limits, which are different from IMO resolution A.468 (Ⅻ) Application to commercial ships of all sizes. Current Code : New ships of 1,600GT and over. Some types of ships, such as fishing vessels and dynamically support craft, don’t be applied.

7. Proposals for noise level limits in DE53/10 7

8. Proposalfor amendments of IMO resolution A.468 (Ⅻ) Chapter 2 : Operating conditions for measurement At a load of minimum 90% of the installed maximum continuous rating (MCR) In connection with dynamic positioning if this is a general part of the ship’s operation Current Code : The main propulsion machinery should be run at normal design service shaft speed. Chapter 5 : Noise exposure limits Introduction of noise exposure limits according to ISO 1999:1990, LEX,8H=85dB(A) Current Code : LEX,24H=80dB(A) as same as LEX,8H=85dB(A)

9. Proposalfor amendments of IMO resolution A.468 (Ⅻ) Chapter 6 : Acoustic insulation between accommodation spaces The airborne sound insulation of the final design measured in ship – the apparent reduction factor R’ｗ, must not be more than 2dB worse than the stipulated reduction factors Rｗ.

10. Discussion and action of the Sub-Committee in DE53 The Sub-Committee agreed as following views. The Code on Noise Levels on Board Ships should be revised as a first step. The revised Code should not be applied to existing ships. Differences in ship types and sizes should be taken into account. The provisions of the Code should be made mandatory as a second step.

11. Japan’s proposals for a revision of the Code • Noise level limits • The current noise limits stipulated in the Code should be a basis. The Code should apply to new ships of 1,600GT and over. • Revision of the current noise level limits should be based on technical analysis. • Same noise level limits should be used for machinery spaces regardless of ship size. • Differentiated noise level limits by ship sizes should be used for accommodation spaces. 10,000GT should be used as a threshold for differentiation.

12. Noise levels of machinery spaces and accommodation spaces

13. Japan’s proposals for noise level limits 13

14. Japan’s proposals for a revision of the Code • Values to be used as a yardstick • Predicted values and measured values are possible yardstick for complying with the Code. • It is necessary to develop reliable prediction methods to minimize prediction gaps in case of using predicted value. • Measurement conditions • According to the current Code, the main propulsion machinery should be run at normal design service shaft speed. • Application/exemption of the Code • The Code should be applied to only new ships. • It is practical to keep the current application coverage of the Code as a first step.

15. An example of ship noise level prediction - Statistical Energy Analysis - Generators Main engine Main engine Engine room & accommodation structure model Predicted noise levels and locations of noise sources 15

16. Conclusions • International noise regulations are necessary to ensure seafarers’ health and safety at work. • There are a lot of impacts on ship design and equipment for mandatory noise regulations and a revision of noise level limits in the current Code, IMO resolution A.468 (Ⅻ). • Different sized or typed ships have different noise levels and smaller ships in particular may have difficulty in complying with the Code. • Further discussions are necessary to develop international noise regulations with sufficient experiences and information.

17. Thank you for your attention Thank you for your attention