Controlling noise on offshore installation during design...
Transcript of Controlling noise on offshore installation during design...
Lloyd’s Register Energy Conference Safety-driven performance 2012
Controlling noise on offshore installation
during design and commissioning
West Elara case
Philippe Loustau
engineering manager
October 18, 2012
Lloyd’s Register Energy Conference Safety-driven performance 2012
Offshore noise control
• What are the challenges for offshore noise control?
• Compact environment: proximity of noise sources
• Compact environment: little space availability for noise control measure
• Use of high power equipment: high strength of noise sources
• Rig weight must be kept under control
• Drilling assets specificities
• Moving around the world and need to comply with local regulations
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Noise Damage
Factors which increase the risk of hearing damages
• Duration
• Volume
• High frequencies more than low
• Pure tones more than broadband noise
• Strong sound impulses
• Individual sensitivity (glass hear)
Secondary adverse effect
• Stress
• Tinnitus• High blood pressure
• Changed breathed rhythm• Reduced power of concentration
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Typical NORSOK S-002 scheme
• NORSOK S-002 regulation suggests a framework for performing noise study
• Step 1: Establish noise specification for equipment through noise maps
calculations, using baseline sound level from experience
• Step 2: Update noise maps with OEMs data (working with the noise source)
• Step 3: Implement noise control measures if needed (working with the
noise transfer path)
• Step 4: Implement signaling for hearing protection if an area cannot reach
the noise level target (working at the receiver)
• Noise is not only propagating airborne, structure borne propagation is not to
be neglected.
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West Elara assessment – facility presentation
: 1.5 mm steel plate
: 1.5+3 mm steel plate
: 2+3 mm steel plate + viscoelastic glue
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West Elara assessment – requirements
Area noise level
• Per Norsok S-002
• From 45 dB(A) for medical room to 110 dB(A) for unmanned machinery room or emergency generator room
Sound insulation
• From 35 to 45 dB between cabins in the living quarter
Other acoustic requirements
• Corridors, not more than 5 dB more than the quiet room noise level (working
area)
• Access to walkways to permanently manned areas should be provided without
passing through a zone with a noise level above 83 dB(A)
Vibration Exposure
• Table from Norsok for human body vibration (acceleration levels depending on
frequency)
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West Elara assessment – living quarters
• Area noise level
• Laundry room (rigid mounting)
• Piping vibration (rigid mounting)
• Equipment vibration (rigid mounting)
• Sound Insulation between cabins
• From 31dB to 38dB. Below required 40 dB.
• Vibration exposure
• Equipment vibration (rigid mounting)
0 10 20 30 40 50 60 70 80 90
partition panel (towards desk)
Partition panel (towards corridor)
HVAC (supply)
HVAC (extract)
Ceiling
Window
Lining panel
Floor
Door
Lp [dBA, ref. 20 microPa]
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West Elara assessment – utility area
• Mechanical workshop
• Next to the engine room and separation by a single steel bulkhead covered with fire protection and a single door
• Influence from pump room identified during testing
• Platform deck
• Mud lab: likely excess of area noise due to poor sound isolation properties of door
• Main Deck
• High noise level from extraction fan 85 dB(A)
• HVAC contribution
• Significant excess from +6dB in rubber good store to +26dB in electrical workshop
• PA-system intelligibility
• Recommended RASTI of 0.7 in recreation areas and 0.35 in work areas with up to 85 dB(A) noise level
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Step by step procedure for troubleshooting
1. Noise survey including determination of sound power
2. Analyze the survey
3. Suggest noise reducing remedies including the likelihood
of the cause
4. Client choose noise insulation
5. Verification by measuring
6. Evaluation of changes
Lloyd’s Register Energy Conference Safety-driven performance 2012
Offshore noise control• Noise control measure for offshore installation
• Acoustic control• Sound insulation• Noise from pipes and valves• Noise attenuating enclosure• Silencers• Vibration isolation
• Other conditions to take into consideration
• Resistance to water / oil• Maintenance (washing / cleaning)• Impact strength• Fire• Paint• Corrosion condition (CUI …)
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Partition panels covered with steel plate in test cabinActual panel not performing according to specMock up cabin built for testing
Examples of recommendations – living quarters
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Air exhaust - silencers
Air exhaust and inlet on main deck injection fans - exhaust line
Example of recommendations – Utility area
Additional silencers
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Forklift corridor
Left: May 2011, Pump Room #2 with forklift corridor before installation of wall.
Right: July 2011, Screening wall installed between equipment and walkway/fork lift area.
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Chiller foundations
Chiller foundations – E deckOn top of some cabins
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Hvac extracts - silencer
HVAC extract on top of driller’s cabin – used to avoid the noise from drill floor to the cabins
Silencer
Example of recommendations – Utility area
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Mechanical workshop – buffer zone
Left: before installation of buffer zone (between engine room) Right: buffer zone installed with an other door
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Conclusion
• As regulators are moving towards more and more stringent regulations in
the area of noise, it is important to consider noise control as early as
possible. It is a complex discipline and a simple review of the initial layout
can save a lot of future headhaches.
• Nevertheless, there are some practical mitigation measures that can be
applied even during construction or in service.
• The NORSOK S-002 standard provides some good guidance and
methodology for noise control.
Lloyd’s Register Energy Conference
Safety-driven performance 2012
For more information, please contact:
Philippe Loustauengineering manager
Lloyd’s Register Energy Americas, Inc.
1330 Enclave Parkway, Suite 200
Houston, Texas 77077
T +1 281 649 2259
w www.lrenergy.org
Lloyd’s Register Energy Conference
Safety-driven performance 2012
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