Guidance Notes On Noise And Vibration Control For .
GUIDANCE NOTES ONNOISE AND VIBRATION CONTROL FOR INHABITEDSPACESSEPTEMBER 2017American Bureau of ShippingIncorporated by Act of Legislature ofthe State of New York 1862 2017 American Bureau of Shipping. All rights reserved.1701 City Plaza DriveSpring, TX 77389 USA
Foreword (1 September 2017)Working and living onboard vessels imposes a series of generally low-frequency mechanical vibrations aswell as single-impulse shock loads on the human body. Also, exposure to noise is characteristic aboardvessels.Low-frequency vibrations are created by vessel motions, which are produced by the various sea states inconjunction with vessel speed and point of sail. These motions can result in motion sickness, bodyinstability, interruptions of task performance, sleep interruption and fatigue, increased health riskaggravated by shock loads due to slam, and reduced human efficiency.Higher-frequency vibration influences comfort and is often associated with rotating machinery. Theimposition of higher frequency vibrations (about 1 to 80 Hz) induces corresponding motions and forceswithin the human body creating discomfort and reduced human efficiency.With regard to noise, the above can similarly affect exposed humans, notably with sleep interruption andresulting fatigue, discomfort, and reduced efficiency. Also of concern are transient and permanent hearingloss, masking of audible signals, and interruption of speech communication.The concerns related to levels and characteristics of noise and vibration are covered in a series of ABSGuides related to habitability on ships and offshore structures*. To be granted any of the associatedhabitability notations, specific noise and vibration criteria must be met. ABS clients in pursuit of thesenotations have requested guidance on how to control levels of noise and vibration in inhabited spaces. As aresult, these Guidance Notes for Noise and Vibration Control in Inhabited Spaces have been created.The information presented in this document is for guidance only, and is intended to support vesseldesigners and operators in controlling vessel noise and vibration in the general case, and more specificallyin meeting the requirements of the ABS Habitability Guides. Adherence to some or all of the guidance inthis document affords no guarantee that a habitability notation will be granted.The September 2017 edition of these Guidance Notes incorporates information from the new IMO Code onNoise Levels On-board Ships (IMO Resolution MSC.337(91)) and the International Labour Organization’sMaritime Labour Convention (ILO MLC).These Guidance Notes become effective on the first day of the month of publication.Users are advised to check periodically on the ABS website www.eagle.org to verify that this version ofthese Guidance Notes is the most current.We welcome your feedback. Comments or suggestions can be sent electronically by email torsd@eagle.org.Notes:* The ABS Habitability Guides are: ABS Guide for Crew Habitability on Ships ABS Guide for Crew Habitability on Workboats ABS Guide for Crew Habitability on Offshore Installations ABS Guide for Crew Habitability on Mobile Offshore Drilling Units (MODUs) ABS Guide for Habitability of Industrial Personnel on Accommodation VesselsABS GUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES 2017ii
GUIDANCE NOTES ONNOISE AND VIBRATION CONTROL FOR ion. 61.1General. 61.3Addressing Noise and Vibration (1 September 2017). 61.5New Industry Requirements (1 September 2017). 63Application (1 September 2017). 85Scope (1 September 2017).87Terminology. 8SECTION2Vibration.141Background (1 September 2017).143Scope (1 September 2017).145Overview of Shipboard Vibration. 145.1Elastic Vibration. 145.3Vibration Study and Source Design (1 September2017).147Sources of Vibration. 157.1Machinery Excitation.157.3Propulsion and Shafting Excitation. 167.5Hydrodynamic Excitation (1 September 2017). 179Hull and Structure Vibration Response (1 September 2017).179.1Global Response. 179.3Local Response. 1811Shipboard Vibration Modeling.1811.1General. 1811.3Finite Element Analysis. 1911.5Vibration Calculation by Empirical Methods. 2113Design for Low Vibration.2113.1General. 2113.3Vibration Control Plan.2213.5Hull Structure Treatment.2413.7Propeller Treatment. 2413.9Mechanical Source Treatment. 2513.11 Sea Trials (1 September 2017).26ABS GUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES 2017iii
1517Implementation (1 September 2017). 2715.1Quality Assurance.2715.3Trials (1 September 2017). 2715.5Material Selection. 27Summary (1 September 2017). 28FIGURE 1FIGURE 2FIGURE 3FIGURE 4FIGURE 5SECTION3Example of FEA Model of a Cargo Vessel. 19Flexural Modes of a Cargo Vessel. 20Deckhouse Model and Bending Modes. 20Overall Procedure for Ship Vibration Assessment. 22Vibration Control Plan – Engineering Flow Chart.23Noise. 29Background (1 September 2017).29Scope (1 September 2017).29Overview of Shipboard Noise (1 September 2017). 295.1Sound Pressure Level. 295.3Frequency Range. 297Sources of Noise. 307.1Propulsion Systems. 307.3Machinery. 307.5Heating, Ventilation, and Air Conditioning (HVAC)Systems. 327.7Piping (1 September 2017).327.9Other Sources.329Source-Path-Receiver Process. 339.1General (1 September 2017). 339.3Acoustic Design and Modeling for the Selection ofTreatments.349.5Proper Installation of Treatments (1 September 2017).3411Shipboard Noise Modeling.3411.1General. 3411.3Source-Path-Receiver Modeling.3511.5SNAME Design Guide and Supplement. 3611.7Analytical Tools. 3711.9Finite Element Method (1 September 2017).3711.11 Other Modeling Approaches (1 September 2017). 3713Design for Low Noise Levels. 3713.1Noise Control Plan.3813.3Machinery and Other Source Treatments.3913.5Path Treatments. 4113.7Receiver Treatments.4713.9HVAC Treatments. 4813.11 Propulsion Treatments.52135ABS GUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES 2017iv
13.1313.151517Piping System Treatments.52Treatment Summary. 5313.17 Fire Safety of Treatments (1 September 2017). 54Implementation (1 September 2017). 5415.1Quality Assurance.5515.3Trials. 5515.5Material Selection. 55Summary (1 September 2017). 55TABLE 1TABLE 2TABLE 3Length of Duct Proceeding Fitting.50Maximum Airflow for Various Noise Ratings. 51List of Treatments and Effectiveness. 53FIGURE 1FIGURE 2FIGURE 3FIGURE 4FIGURE 5FIGURE 6FIGURE 7Airborne/Structure-borne Source/Path.31Noise Flow Chart.33Noise Control Plan – Engineering Flow Chart.39Unconstrained Tile Damping Applied to Hull Side. 4490 Flexible Hose Connection.46Floating Floor Treatment.48Typical Resilient Pipe Support. 53ABS GUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES 2017v
SECTION1General1Introduction1.1GeneralWork-related hearing loss and vibration-related health effects are critical workplace safety and healthissues. Seafarers may experience motion sickness, body instability, fatigue, and noise-induced hearing loss,one of the most common occupational diseases.Adverse/improper noise and vibration levels can also cause speech interference, mask warning signals,interfere with concentration and thought processes, disrupt sleep, and create harmful living and workingconditions. If designed appropriately, however, vessels complying with proper noise and vibration levelscan provide an environment for improved crew performance, safety, comfort, and communication, andhave an overall positive psychological effect on seafarers.1.3Addressing Noise and Vibration (1 September 2017)The recommended way to meet noise and vibration criteria is to undertake noise and vibration analysesvery early in the design process and apply appropriate controls to mitigate areas of potential concern.Noise and vibration analysis includes: Identifying sources of noise and vibration Modeling noise and vibration within the vessel Calculation of exciting forces (frequency and amplitude) Location of force application and response of the vessel structure in the positions of interest Modeling the source-path-receiver phenomenon Using this information to review the existing design for opportunities to improve noise and vibrationlevelsTherefore, this analysis requires methods which can use design information as input data and calculate theexpected noise and vibration levels at positions of interest. It is suggested that the exciting forces should bedetermined for conditions when the propulsion machinery runs at not less than 80 percent maximumcontinuous rating (MCR) for noise and between 80 and 105% for structural vibration analyses.1.5New Industry Requirements (1 September 2017)There are several industry requirements relating to noise exposure levels for seafarers. These include theIMO Code on Noise and the International Labour Organization’s (ILO) Maritime Labour Convention,2006.1.5.1IMO Code on NoiseOn 1 July 2014, the International Convention for the Safety of Life at Sea (SOLAS) was amendedto make the “Code on Noise Levels On Board Ships” (the Noise Code) mandatory for newvessels.The IMO Code on Noise Levels On-board Ships (IMO Resolution MSC.337(91)) is now in forceand includes requirements limiting noise for certain types of vessels in excess of 1600 gross tons.ABS GUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES 20176
Section1General1The Code also includes noise from the operation of thrusters and from noise in port that is relatedto cargo operations. There are also requirements for acoustic insulation.This Resolution sets out mandatory maximum noise level limits for machinery spaces, controlrooms, workshops, accommodation and other spaces on board ships. The Code supersedes theprevious non-mandatory Code, adopted in 1981 by resolution A.468 (XII).The purpose of the new Code is to provide standards on preventing noise levels hazardous tohuman health and reduce seafarers’ exposure to such noise levels. It gives consideration to theneed for communication, the ability to hear audible alarms, the protection of seafarers frompossible noise-induced hearing loss, and the provision of an acceptable degree of comfort duringrest hours.The new IMO criteria have been incorporated into the existing ABS suite of Habitability Guidessupporting the various HAB notations. These are the:1.5.2 ABS Guide for Crew Habitability on Ships ABS Guide for Crew Habitability on Workboats ABS Guide for Crew Habitability on Offshore Installations ABS Guide for Crew Habitability on Mobile Offshore Drilling Units (MODUs) ABS Guide for Habitability of Industrial Personnel on Accommodation VesselsILO MLC 2006The International Labor Organization (ILO) Maritime Labour Convention (MLC), 2006 wasratified and came into force in August of 2013 by port States having adopted the Convention.Within the maritime sphere, the ILO provides legal instruments aimed at protecting and improvingseafarers’ working and living conditions. The Convention provides the, as yet, mostcomprehensive Code regarding seafarers’ rights, and the obligations of States and shipowners withrespect to these rights. The Convention incorporates the fundamental principles of many ILOConventions and brings together and updates 68 existing ILO instruments (Conventions andRecommendations) into one document.The MLC has Regulations, both objective and subjective, relating to whole-body vibration andnoise levels aboard vessels. Examples are listed below:i)Regulation A3.1.6(h) states: “accommodation and recreational and catering facilitiesshall meet the requirements in Regulation 4.3, and the related provisions in the Code, onhealth and safety protection and accident prevention, with respect to preventing the risk ofexposure to hazardous levels of noise and vibration and other ambient factors andchemicals on board ships, and to provide an acceptable occupational and on-board livingenvironment for seafarers.”ii)MLC Regulation A3.1.6(h) calls out Regulation 4.3. Below are listed the physical designand arrangement related aspects of Regulation 4.3 including:a)A4.3.1(b) “reasonable precautions to prevent occupational accidents, injuriesand diseases on board ship, including measures to reduce and prevent the risk ofexposure to harmful levels of ambient factors and chemicals as well as the risk ofinjury or disease that may arise from the use of equipment and machinery onboard ships.”Note:b)Ambient factors refer to improper levels of vibration, noise, lighting, and indoorclimatic qualities.A4.3.2(a) “take account of relevant international instruments dealing withoccupational safety and health protection in general and with specific risks, andaddress all matters relevant to the prevention of occupational accidents, injuriesABS GUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES 20177
Section1General1and diseases that may be applicable to the work of seafarers and particularlythose which are specific to maritime employment;”Note:c)Occupational disease refers to disorders such as noise-induced hearing loss, tinnitus,and musculoskeletal injuries/disorders (e.g., lower and upper back and neck issues).A4.3.4 “Compliance with the requirements of applicable internationalinstruments on the acceptable levels of exposure to workplace hazards on boardships and on the development and implementation of ships’ occupational safetyand health policies and programmes shall be considered as meeting therequirements of this Convention.” The more common international instrumentsrelated to the “ambient factors” of noise and vibration are the new IMO Code onNoise and ISO 6954: 2000, Mechanical vibration – Guidelines for themeasurement, reporting and evaluation of vibration with regard to habitability onpassenger and merchant ships.The IMO Code on Noise and the ISO 6954 vibration criteria have been incorporated into theexisting ABS suite of Habitability Guides supporting the various HAB notations and into the ABSGuide for Compliance with the ILO MLC, 2006 Title 3 Requirements, and the associated MLCACCOM notation. Both of these notations support the demonstration of vessel compliance withthe physical design and arrangement requirements, including acceptable conditions of onboardambient environmental factors of MLC Title 3. Neither of these Guides address the procedural ormanagement system requirements required by the ILO MLC.3Application (1 September 2017)These Guidance Notes are intended to assist the marine community (shipyards, designers, regulators, andowners) in addressing noise and vibration issues and important design parameters. The information inthese Guidance Notes is recommendatory and should be strongly considered when designing any newvessel in order to provide the safest and most productive working environment for seafarers. The cost offixing noise or vibration issues can be as much as ten times more expensive after construction than ifincorporated into the design from the preliminary design stage. Therefore, careful consideration should begiven to designing in noise and vibration reduction elements.5Scope (1 September 2017)These Guidance Notes are intended to provide a basic understanding and overview of the critical factorscontrolling noise and low-frequency vibrations onboard vessels and to gain better understanding of theimportant concepts of noise and vibration, design parameters, terminology, analysis methods, acoustic andvibration treatments, and other important data to consider when dealing with noise and vibration.These Guidance Notes also include basic terminology and definitions of acoustic and vib
NOISE AND VIBRATION CONTROL FOR INHABITED SPACES . interfere with concentration and thought processes, disrupt sleep, and create harmful living and working conditions. If designed appropriately, however, vessels complying with proper noise and vibration levels can provide an environment for improved crew performance, safety, comfort, and .
Noise Figure Overview of Noise Measurement Methods 4 White Paper Noise Measurements The noise contribution from circuit elements is usually defined in terms of noise figure, noise factor or noise temperature. These are terms that quantify the amount of noise that a circuit element adds to a signal.
with standard guidance, and CDA arrivals with the new low noise guidance, was developed to assist in the testing and evaluation of the low noise guidance concept. Results of the simulation testing showed the low noise guidance was easy to use by airline pilot test subjects and effective in achieving the desired noise reduction.
noise and tire noise. The contribution rate of tire noise is high when the vehicle is running at a constant speed of 50 km/h, reaching 86-100%, indicating tire noise is the main noise source [1]. Therefore, reducing tire noise is important for reducing the overall noise of the vehicle and controlling noise pollution [2].
The Noise Element of a General Plan is a tool for including noise control in the planning process in order to maintain compatible land use with environmental noise levels. This Noise Element identifies noise sensitive land uses and noise sources, and defines areas of noise impact for the purpose of
7 LNA Metrics: Noise Figure Noise factor is defined by the ratio of output SNR and input SNR. Noise figure is the dB form of noise factor. Noise figure shows the degradation of signal's SNR due to the circuits that the signal passes. Noise factor of cascaded system: LNA's noise factor directly appears in the total noise factor of the system.
Figure 1: Power spectral density of white noise overlaid by flicker noise. Figure 2: Flicker noise generated from white noise. 1.1 The nature of flicker noise Looking at processes generating flicker noise in the time domain instead of the frequency domain gives us much more insight into the nature of flicker noise.
the noise figure of the receiver. Noise figure has nothing to do with modulation or demodula-tion. It is independent of the modulation format and of the fidelity of modulators and demodulators. Noise figure is, therefore, a more general concept than noise-quieting used to indicate the sensitivity of FM receivers or BER used in digital .
The Noise figure is the amount of noise power added by the electronic circuitry in the receiver to the thermal noise power from the input of the receiver. The thermal noise at the input to the receiver passes through to the demodulator. This noise is present in the receive channel and cannot be removed. The noise figure of circuits in the .
