Marine/Off Shore
Marine / Offshore Platform On-board HVAC and Mechanical Noise and Vibration Measurements
Marine / Offshore drilling platforms are highly complex constructions, their management requires pleasant working environment for maximizing profitability.
The setting up a vibration Condition Monitoring programme in the Offshore Oil & Gas industry is much challenging. Platform staff is rarely trained in highly noisy & vibrational condition. In this harsh challenging environment, collecting reliable noise and vibration measurement data while minimizing the time spent on the task are practical requirements for modern maintenance programmes.
In the offshore industry, Noisy & Vibrational Condition Monitoring is now common practice. It is indeed essential to carry out noise & vibration analysis on critical machines in order to control and minimize unplanned shutdowns due to unforeseen machinery failures.
However, operators are facing specific challenges due to the day-to-day management of offshore platforms. Sub- contracting the entire process to a service company is also not a sustainable option, as transporting service engineers by helicopter to the platform and back is costly and time consuming, and it also requires a lot of planning.
The related data collection is often carried out with a handheld vibration analyser and a sensor attached to a mounting magnet.
This method provide some limitations in terms of data reliability especially when the measurement locations are hard to reach. For the vibration analysis the collected data can turn out to be meaning-less when the readings were not taken at the exact same position across the various measurements.
In the hazardous areas, the collection of vibration readings using handheld devices can also present highly risks for untrained working staff since the assets to be monitored are remote place (e.g. drilling platforms), machines or equipment’s are hard to reach and located in hazardous location. For the operators of pumping stations, drilling platforms, refineries with intrinsically safe areas, the safety norms of the employees must be ensured always in higher priority basis. Therefore operators are interested in keeping the vibration data collection process as short and easy as possible in order to decrease the exposure of the risks.
Specifically in the marine / offshore sector, the requirements for data integrity are very high because of data analysis is carried out onshore by in-house or external service providers.
Related vibration data collection should be quick, safe and reliable. Ideally, online monitoring systems automatically take care of the critical equipment’s health.
Application
This Rule Note provides procedural and technical requirements for the assignment of the following additional class notations:
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COMFORT HEALTH-NOISE- g with regard to noise criteria
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COMFORT HEALTH-VIBRATION - g with regard to vibration criteria
With g = 1 or 2 (1 corresponding to the best level) each class notations may be assigned separately.
Comfort and Health on-board Offshore Units
The additional class notations Comfort Health – Noise and Comfort Health – VIBRATION may be assigned to all offshore units in accordance with Part – A of NR-445 Rules for the Classification of Offshore Units.
Principles: This Rule Note deals with the habitability of offshore units with regard to for noise and vibrations. The assessment is based on two different requirements:
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Comfort requirements applicable for accommodation, service, navigation and control spaces.
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Health requirements so as to protect workers from risk arising from physical agent (noise and vibration levels are given for working spaces).
The assigned grade is made on the basis of measurements performed by, or under supervision of an acoustic and vibration specialist from the Society during building stage, sea trials or in service. However, measurements may be performed by another acoustic and vibration specialist from external company.
Regulations - Standards
This Rule Note take into account various international standards and are deemed to preserve their general principles. This Rule Note refer to the following standards applicable to noise:
- ISO 31/VII, Quantities and units of acoustics
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IEC Publication 61260, Octave, half-octave and third octave band filters
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IMO Resolution MSC.337(91), Adoption of the Code on noise level on-board ships)
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ISO 717, Acoustics – Rating of sound insulation in buildings and of building elements
Part 1, Airborne sound insulation in buildings and interior elements
- ISO 9612, Acoustics – Guidelines for measurement and assessment of exposure to noise in a working environment
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ISO 1996, Acoustics – Description, measurement and assessment of environmental noise
Part 1, Basic quantities and assessment procedure
Part 2, Determination of environmental noise levels
- ISO 1999, Acoustics – Determination of occupational noise exposure and estimation of noise-induced hearing impairment
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ISO 3382, Acoustics – Measurement of the reverberation time of rooms with reference to other acoustical parameters
Part 1, Performance spaces
Part 2, Reverberation time in ordinary rooms
- ISO 4869, Acoustics – Hearing protectors
Part 2, Estimation of effective A-weighted sound pressure levels when hearing protectors are worn
- ISO 16283-1, Acoustics – Field measurement of sound insulation in buildings and of building elements
Part 1: Airborne sound insulation
This rule refer to the following standards applicable to vibration:
- ISO 2041, Vibration and shock – Vocabulary
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ISO 6954, Mechanical vibration and shock – Guidelines for the overall evaluation of vibration in merchant ships
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ISO 2631-1 Mechanical vibration and shock – Evaluation of human exposure to whole-body vibration
Part 1 General Requirements
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ISO 8041, Human response to vibration – Measuring instrumentation.