Section 1 General requirements

1.1.1 These Rules set down the criteria for the assessment of the noise and vibration on ships and are applied in addition to the other relevant requirements of the Rules and Regulations for the Classification of Ships (hereinafter referred to as the Rules for Ships).

1.1.2 The requirements of this chapter may be applied where no other statutory requirements exist.

1.1.3 These Rules provide for two alternatives:

1. Class Notations which indicate that the ship has been assessed and complies with noise and vibration criteria in these Rules and that a periodic survey regime has been established for the lifetime of the ship.

2. Certificate of Compliance which provides evidence that the ship has been assessed and found to comply with the noise and vibration criteria in these Rules.

1.1.4 Spaces that comply with the noise level limits specified in Table 12.2.4 Crew work areas - maximum noise levels in dB(A) and under Acceptance Numeral 3 in Table 12.2.1 Passenger ships - Maximum noise levels in dB(A) and Table 12.2.3 Crew accommodation - Maximum noise levels in dB(A), will meet the requirements of section 4 of IMO Resolution MSC.337(91) – Adoption of the Code on Noise Levels on Board Ships – (Adopted on 30 November 2012)The Annex below is consolidated into Resolution MSC.337(91), when measured in accordance with the requirements of Chapters 2 and 3 of that Resolution.

1.1.5 Spaces that comply with the noise level limits specified under Acceptance Numerals 1 and 2 in Table 12.2.1 Passenger ships - Maximum noise levels in dB(A) and Table 12.2.3 Crew accommodation - Maximum noise levels in dB(A), will achieve enhanced levels of passenger and crew comfort as applicable, when measured in accordance with the requirements of Chapters 2 and 3 of IMO Resolution MSC.337(91) – Adoption of the Code on Noise Levels on Board Ships – (Adopted on 30 November 2012)The Annex below is consolidated into Resolution MSC.337(91). All vessels can apply for Acceptance Numerals 1 and 2.

1.1.6 These Rules recognise existing National and International Standards and specify levels of noise and vibration currently achievable using good engineering practice. Compliance with these requirements will be assessed by review of procedures, inspection and measurement of the relevant parameters and pre-survey reviews. Inspections and measurements are to be conducted, witnessed or assessed by LR's Surveyors unless otherwise agreed by Clasifications Register (hereinafter referred to as LR).

1.1.7 Accommodation comfort is a function of ship type and layout. These Rules address two types of ship:

1. Passenger (e.g. cruise ships, ro-ro ferries).

2. Cargo (e.g. container ships, tankers).

1.1.8 These Rules include levels of noise and vibration which should be verified by measurements following completion of the ship. It is recommended that the Builders undertake calculations of noise and vibration characteristics so that any potential problem areas can be identified and control measures implemented.

1.1.9 The sound pressure levels for audible alarms and public address systems fitted in accordance with other sections of the Rules are to satisfy IMO Resolution A.1021(26) – Code on Alerts and Indicators, 2009 – (Adopted on 2 December 2009) .

1.2.1  Passenger spaces are defined as all areas intended for passenger use, and include the following:

1. Passenger cabins.

2. Public spaces (e.g. restaurants, hospital, lounges, reading and games rooms, gymnasiums, corridors, shops).

3. Open deck recreation areas.

1.2.2  Crew spaces are defined as all areas intended for crew use only, and include the following:

1. Accommodation spaces (e.g. cabins, offices, mess rooms, recreation rooms).

2. Work spaces.

3. Navigation spaces.

1.2.3  Noise level is defined as the A-weighted energy equivalent sound pressure level measured in accordance with ISO 2923.

1.2.4  Vibration level is defined by the application of ISO 20283-5.

The vibration level is defined as the overall frequency weighted r.m.s. value of vibration during a period of steady-state operation over the frequency range 1 to 80 Hz.

1.3.1 The class notations described in Pt 7, Ch 12, 1.3 Class notations 1.3.2 to Pt 7, Ch 12, 1.3 Class notations 1.3.6 provide standards for noise and vibration levels in different spaces at the time of delivery and during the ship's life if substantial changes to the machinery installation or interior arrangements are made.

1.3.2 The PAC (Passenger Accommodation Comfort), CAC (Crew Accommodation Comfort) and PCAC (Passenger and Crew Accommodation Comfort) notations are optional and are primarily intended to apply to passenger ships. If requested, however, any ship can be assessed for compliance, using these requirements as the basis for the assessment and an LR Certificate of Compliance issued (see Pt 7, Ch 12, 1.1 Scope 1.1.3.(b) and Pt 7, Ch 12, 1.4 Certificate of Compliance).

1.3.3 The PAC notation indicates that the passenger accommodation meets the acceptance criteria whilst the CAC notation indicates that the crew accommodation and work areas meet the acceptance criteria. The PCAC notation indicates that the passenger and crew spaces both meet the acceptance criteria.

1.3.4 For ships which achieve the noise and vibration comfort standards specified in these Rules, the notation PAC, CAC or PCAC will be assigned.

1.3.5 Following the PAC or CAC notation, numerals 1, 2 or 3 will indicate the acceptance criteria to which the noise and vibration levels have been assessed. In the case of the PCAC notation, two numerals will be assigned. The first will indicate the acceptance criteria for passenger accommodation, whilst the second will indicate the crew comfort criteria.

1.3.6 For particular vessels, impact insulation and transient noise in accordance with Pt 7, Ch 12, 2.5 Impact insulation and Pt 7, Ch 12, 2.6 Transient noise together with any additional or more stringent noise and vibration criteria may be assessed within the scope of the notations where agreed between the Owner, Builder and LR.

1.4.1 A Certificate of Compliance records that a ship has been designed and constructed to satisfy the noise and vibration criteria contained in these Rules. This is to be confirmed by measurements and reporting in accordance with Sections Pt 7, Ch 12, 4 Testing and Pt 7, Ch 12, 5 Noise and vibration survey reporting.

1.4.2 A Certificate of Compliance is optional and if requested, any ship can be assessed for compliance using the Rule requirements as basis for assessment.

1.4.3 Where noise and vibration levels are at variance with those prescribed by these Rules, these will be added to the certificate for information purposes.

1.4.4 A Certificate of Compliance will be issued after the initial survey required by Pt 7, Ch 12, 6 Non-periodical survey requirements.