1、 Guidance Notes on Noise and Vibration Control for Inhabited Spaces GUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES JULY 2014 American Bureau of Shipping Incorporated by Act of Legislature of the State of New York 1862 Copyright 2014 American Bureau of Shipping ABS Plaza 16855 Nor
2、thchase Drive Houston, TX 77060 USA ii ABSGUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES .2014 Foreword Foreword Working and living onboard vessels imposes a series of generally low-frequency mechanical vibrations, as well as single-impulse shock loads on the human body. Also, ex
3、posure to noise is characteristic aboard vessels. Low-frequency vibrations are imposed by vessel motions, which are produced by the various sea states in conjunction with vessel speed and point of sail. These motions can result in motion sickness, body instability, interruptions of task performance,
4、 sleep interruption and fatigue, increased health risk aggravated by shock loads due to slam, and reduced human efficiency. Higher-frequency vibration influences comfort and is often associated with rotating machinery. The imposition of higher frequency vibrations (about 1 to 80 Hz) induces correspo
5、nding motions and forces within the human body creating discomfort and reduced human efficiency. With regard to noise, the above can similarly affect exposed humans, notably with sleep interruption and resulting fatigue, discomfort, and reduced efficiency. Also of concern are transient and permanent
6、 hearing loss, 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 ABS Guides related to habitability on ships and offshore structures*. To be granted any of the associated habitabi
7、lity notations, specific noise and vibration criteria must be met. ABS clients in pursuit of these notations have requested guidance on how to control levels of noise and vibration in inhabited spaces. As a result, these Guidance Notes for Noise and Vibration Control in Inhabited Spaces have been cr
8、eated. The information presented in this document is for guidance only, and is intended to support vessel designers and operators in controlling vessel noise and vibration in the general case, and more specifically in meeting the requirements of the ABS Habitability Guides. Following some or all of
9、the guidance in this document affords no guarantee that a habitability notation will be granted. 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 of these Guidance
10、Notes is the most current. We welcome your feedback. Comments or suggestions can be sent electronically by email to rsdeagle.org. * Note: 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
11、 Installations ABS Guide for Crew Habitability on Mobile Offshore Drilling Units (MODUs) ABSGUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES .2014 iii T able of Contents GUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES CONTENTS SECTION 1 General 1 1 Introduction .
12、 1 1.1 General 1 1.3 Addressing Noise and Vibration 1 3 Application 1 5 Scope 1 7 Terminology 2 SECTION 2 Vibration 7 1 Background . 7 3 Scope 7 5 Overview of Shipboard Vibration 7 5.1 Elastic Vibration . 7 5.3 Vibration Study and Source Design . 8 7 Sources of Vibration 8 7.1 Machinery Excitation .
13、 8 7.3 Propulsion and Shafting Excitation 9 9 Hull and Structure Vibration Response . 9 9.1 Global Response . 9 9.3 Local Response . 10 11 Shipboard Vibration Modeling . 10 11.1 General 10 11.3 Finite Element Analysis . 11 11.5 Vibration Calculation by Empirical Methods 13 13 Design for Low Vibratio
14、n . 13 13.1 General 13 13.3 Vibration Control Plan . 14 13.5 Hull Structure Treatment . 16 13.7 Propeller Treatment . 16 13.9 Mechanical Source Treatment . 17 13.11 Sea Trials 17 iv ABSGUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES .2014 15 Implementation . 18 15.1 Quality Assura
15、nce 18 15.3 Trials 18 15.5 Material Selection 19 15.7 Consultant/Contractor Selection 19 17 Summary . 19 FIGURE 1 Example of FEA Model of a Cargo Vessel . 11 FIGURE 2 Flexural Modes of a Cargo Vessel 12 FIGURE 3 Deckhouse Model and Bending Modes 12 FIGURE 4 Overall Procedure for Ship Vibration Asses
16、sment 14 FIGURE 5 Vibration Control Plan Engineering Flow Chart . 15 SECTION 3 Noise 20 1 Background . 20 3 Scope 20 5 Overview of Shipboard Noise . 20 5.1 Sound Pressure Level . 20 5.3 Frequency Range 20 7 Sources of Noise . 21 7.1 Propulsion Systems . 21 7.3 Machinery 21 7.5 Heating, Ventilation,
17、and Air Conditioning (HVAC) Systems . 22 7.7 Piping . 23 7.9 Other Sources . 23 9 Source-Path-Receiver Process. 23 9.1 General 23 9.3 Acoustic Design and Modeling for the Selection of Treatments 24 9.5 Proper Installation of Treatments . 24 11 Shipboard Noise Modeling 25 11.1 General 25 11.3 Source-
18、Path-Receiver Modeling 26 11.5 SNAME Design Guide and Supplement 27 11.7 NOISE Software 27 11.9 Other Modeling Approaches 27 13 Design for Low Noise Levels 27 13.1 Noise Control Plan . 27 13.3 Machinery and Other Source Treatments 29 13.5 Path Treatments 31 13.7 Receiver Treatments . 35 13.9 HVAC Tr
19、eatments 37 13.11 Propulsion Treatments . 40 13.13 Piping System Treatments . 40 13.15 Treatment Summary 41 ABSGUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES .2014 v 15 Implementation . 42 15.1 Quality Assurance . 42 15.3 Trials . 42 15.5 Material Selection 42 15.7 Consultant/Con
20、tractor Selection 42 17 Summary . 43 TABLE 1 Length of Duct Proceeding Fitting . 38 TABLE 2 Maximum Airflow for Various Noise Ratings . 40 TABLE 3 List of Treatments and Effectiveness 41 FIGURE 1 Airborne/Structure-borne Source/Path . 22 FIGURE 2 Noise Flow Chart. 24 FIGURE 3 Noise Control Plan Engi
21、neering Flow Chart 28 FIGURE 4 Unconstrained Tile Damping Applied to Hull Side 33 FIGURE 5 90 Flexible Hose Connection. 34 FIGURE 6 Floating Floor Treatment . 36 FIGURE 7 Typical Resilient Pipe Support 41 This Page Intentionally Left Blank ABSGUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABIT
22、ED SPACES .2014 1 Section 1: General SECTION 1 General 1 Introduction 1.1 General Work-related hearing loss and vibration-related health effects are critical workplace safety and health issues. Seafarers may experience motion sickness, body instability, fatigue, and noise-induced hearing loss, one o
23、f 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 make living and working conditions more harmful. If designed appropriately, however, v
24、essels complying with proper noise and vibration levels can provide an environment for improved crew performance, safety, comfort, and communication, and have an overall positive psychological effect on seafarers. 1.3 Addressing Noise and Vibration The best way to meet noise and vibration criteria i
25、s to undertake a noise and vibration analysis and apply appropriate controls during the design stage. There are very limited possibilities or opportunities to fix a noise or vibration problem after the vessel is built. Noise and vibration analysis includes: Identifying sources of noise and vibration
26、 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 f
27、or opportunities to improve noise and vibration levels Therefore, this analysis requires methods which can use design information as input data and calculate the expected noise and vibration levels at positions of interest. It is suggested that the exciting forces should be determined for conditions
28、 when the propulsion machinery runs at not less than 80 percent maximum continuous rating. 3 Application These Guidance Notes are intended to assist the marine community (shipyards, designers, regulators, and owners) in addressing noise and vibration issues and important design parameters. The infor
29、mation in these Guidance Notes is recommendatory and should be strongly considered when designing any new vessel in order to provide the safest and most productive working environment possible. The cost of fixing a noise or vibration problem within a vessel is up to ten times more expensive after co
30、nstruction than if incorporated into the design from the preliminary design stage. Therefore, careful consideration should be given to designing in noise and vibration reduction elements. 5 Scope These Guidance Notes are intended to provide a basic understanding and overview of the critical factors
31、controlling noise and low-frequency vibrations onboard vessels and to gain an overview of the important concepts of noise and vibration, design parameters, terminology, analysis methods, acoustic and vibration treatments, and other important data to consider when dealing with noise and vibration. Se
32、ction 1 General 2 ABSGUIDANCE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES .2014 These Guidance Notes also include basic terminology and definitions of acoustic and vibration terms, a description of noise and vibration generating mechanisms, specifics on noise and vibration sources in s
33、hips, information regarding noise and vibration transmission through the hull structure, an overview of methods used for noise and vibration analysis, and noise and vibration control during the design stage or during modernization. With the proper understanding of how noise and vibration is generate
34、d, controlled and measured, maritime vessels can be more easily designed to reduce noise and vibration in a straightforward, economic, and optimal manner, thus improving seafarer levels of habitability and task performance. The main philosophy of these Guidance Notes is that noise and vibration prob
35、lems can be addressed and solved via proper attention to the acoustic design; including program planning, analysis, treatment selection, construction Quality Assurance (QA), and verification testing. 7 Terminology Acceleration: A vector that specifies the time rate of change of velocity (units of m/
36、s2). The acceleration of the vibratory motion of a structure can be specified in terms of the peak, average, or root-mean-square (rms) magnitude of the acceleration in a given direction. In this document, the acceleration levels are given in terms of the rms acceleration amplitude. Acceleration Leve
37、l: LA, in dB, of a vibrating body is 20 times the logarithm to the base 10 of the ratio of the acceleration to a reference acceleration (standard reference acceleration level is 10-3cm/s2). LA= 20 log (a/aref) = 10 log (a/aref)2. Acoustic: For the purposes of this document, “acoustic” refers to both
38、 noise and vibration related phenomena. Acoustic Absorption: The change of sound energy into some other form, usually heat, in passing through a medium or on striking and being reflected from a surface. Acoustic Power: See “sound power” or “sound power level”. Airborne Sound (or Noise): Sound or noi
39、se that is transmitted through air or by means of paths in air. Since air cannot support shear, only pressure waves with longitudinal displacement can be transmitted through air. Amplitude: The value of vibratory response due to a steady state periodic process. Amplitude may be measured as displacem
40、ent, velocity or acceleration and may be presented as a peak level or a root mean square (rms) level. A-weighted Sound Pressure Level: The magnitude of a sound, expressed in decibels (i.e., 20 micropascals); the various frequency components are adjusted according to the A-weighted values given in IE
41、C 61672.1 (2004) in order to account for the frequency response characteristics of the human ear. The symbol is LA, and the unit is dB(A). The measurement LAeqis an equivalent continuous A-weighted sound pressure level, measured over a period of time. Bending Mode: Mode of vibration in which cross-s
42、ections of a beam, shaft, or structure undergo translation and rotation. Type of translational mode usually found in slender structures with evenly distributed mass and stiffness. Calibration Checks: Field calibration of a measuring instrument conducted before and after a field test, using a referen
43、ce calibrated signal or through zero calibration. Comfort: The ability of the crew to use a space for its intended purpose with minimal interference or annoyance from noise. Crest Factor: The ratio of the peak value to the root-mean-square (rms) value of the acceleration after it has been frequency
44、weighted by the appropriate frequency weighting network. Crest Factor = onaccelerati rms weightedonacceleratipeak weightedDamping: The dissipation of energy with time or distance. In this document, damping generally refers to dissipation of vibrating energy in structures. Section 1 General ABSGUIDAN
45、CE NOTES ON NOISE AND VIBRATION CONTROL FOR INHABITED SPACES .2014 3 Decibel (dB): A dimensionless unit of measure of the ratio of two quantities, P1and P2, each of which is equal to or proportional to power. Ten times the logarithm to the base 10 of the ratio, P1/P2, has the dimensions of dB. Direc
46、t Sound Field: A sound field in which energy is flowing outward from the source without interference from surrounding surfaces. The sound field very close to a source, even in a reverberant room, is a direct field. Sound fields outdoors are direct fields at all distances from the source and are refe
47、rred to as “free sound fields” or “free fields”. Duration: Is represented by the length of exposure to sound. Dynamic Positioning: A system to automatically maintain a workboats position and heading by controlling propellers and/or thrusters. Dynamic positioning can maintain a position to a fixed po
48、int over the bottom, or in relation to a moving object (such as another vessel). It can also be used to position the vessel at a favorable angle towards wind, waves, and current. Equivalent Continuous A-weighted Sound Pressure Level: The A-weighted sound pressure level of a notional steady sound, ov
49、er a certain time interval, which would have the same acoustic energy as the variable-loudness real sound under consideration, over that same time interval. The symbol is LAeq; the unit is dB(A). Excitation: A time-dependent stimulus (force or displacement) that produces vibration. Excitation may be transient, random, and periodic. A steady-state periodic excitation, like that produced by propellers or propulsion engine, is of interest in these Guidance Notes. Exciting Frequency: Is the number of cycles of the excitation completed during a given time unit.
