Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Daniel Alvarez, M.Sc.
Senior Consultant, Energy
Lloyd’s Register
Noise Management in Offshore Installations
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Noise
• Source of: stress, high blood pressure, headaches, tiredness, reduction of work efficiency, hearing loss
• May be fatal if personnel cannot hear instructions or alarms.
• Impacts: (1) comfort, (2) working conditions and (3) environment
Offshore Installations
• Compact environment with large amount of noise and vibration sources
• Structure-borne noise play an important role in steel-type structures
• Indoor controlable climate is often required
• Limited space and weight for noise control measures
• Movable facilities may want to comply with regulations globally
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Successful Noise Management through...
• Understanding the targets
• Dialogue contractors - vendors
• Find optimal combination of noise control measures
• All based on Reliable Noise Predictions at early design stage
Value
• Substantial reduction of cost
• Enhance reduction by tailoring control measures to specific
design
• Minimize risk of expensive retroactive noise control
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Noise Prediction Package often includes...
• Outdoor sound propagation study
• Noise at indoor machinery areas
• Noise Insulation Analysis
• Structure-borne noise study
• Evaluation of HVAC Noise
• Vibration studies
• Underwater noise study
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
0
1
2
3
4
5
6
7
8
9
10
11
X (Meter)
Y (M
eter)
108-110
106-108
104-106
102-104
100-102
98-100
96-98
94-96
92-94
90-92
88-90
86-88
84-86
82-84
80-82
78-80
76-78
74-76
72-74
70-72
FWD
Vacuum Unit
Skimmer Tanks
TriptankSand Trap
TankDegasser
Tank
Des
ilter
Tan
k
Cen
trifu
ge
Tan
k
Cat
ch T
ank
Cle
an T
ank
Triptank Pumps Desilter Pumps
Shearing Tank
Shearing Tank Slurry Tank
“The matter is not only to operate them, but to choose the right tool for specific applications”
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Outdoor Sound Propagation Study• Focus on working conditions
• Identifies problem areas and warning signal locations
• Requires knowledge about oil & gas machinery and its noise and vibration characteristics (database)
• Can be used during the entire life cicle for HSE purposes (requires regular updates)
• Allows the evaluation of noise control measures
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Noise at Indoor Machinery Areas• Focus on working conditions
• Identifies problem areas and warning signal locations
• Requires database of machinery noise and vibration characteristics as well as indoor environment properties (Absorption or T60)
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Noise Insulation Analysis
Lp,1 Lp,2 = ?
• Focus on Accommodation Blocks and sensitive areas in noisy environments (control rooms)
• Noise transmission from outdoors as well as noise transmission amongst indoor spaces
• Requires knowledge about material properties (often based on empirical information)
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Structure-borne Noise Study• Focus on Accommodation Blocks
• Requires source strength (energy to structure)
• Requires information about how the energy propagates in the structure (empirical or statistical)
• Requires knowledge in regards to material damping (often flooring)
Lv1
Lv2 Lv3
Lv4
LW2
LW1
LW4
LW3
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Evaluation of HVAC Noise
• Focus on Accommodation Blocks and often affecting working conditions too
• Noise is generated through supply and return ducting (silencer up and downstream)
• Silencers are often cheap solutions but often forgotten creating a space issue
• Empirical information about pressure-drop control devices is often required
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Vibration Studies• Deterministic analysis of supporting structure
• The output refers structural modifications to suit requirements
• Often conducted only for major equipment
Excitation points:
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Vibration Studies (2)• Coarse evaluation of suporting structure
• Selection of anti-vibration mounts as per machinery characteristics
• Database of anti-vibration technology plays an important role
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Underwater Noise Study• The effect of piling of offshore platforms
Overa
ll SEL
(dB
re 1
µPa2s
)
Depth
[m
]
Range [km]1 2 3 4 5 6 7
10
30
50
70
90
180
170
160
150
140
130
120
Seabed
Source
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Underwater Propagation Modelling
Acoustic Finite Element Model of untreated pile vs single-wall cofferdam
Snapshot at 19 ms
Hammer energy 1890 kNm/kJ
Pile length/diameter: 45 m / 5.4 m
Water depth: 25 m
Cofferdam: 50 mm steel, 900 mm air gap
Water Water
Seabed Seabed
Cofferdam
Water-filled pile
Lloyd’s Register services to the energy industry
November 11-14, 2014 Adipec
Conclusions
• Noise may cause significant costs in your project
• Noise may generate considerable damage to your employees
• Theoretical and empirical information in regards to noise and vibration charateristics of machinery, as well as material noise insulation properties play an important role during the design
• Noise and vibration prediction tools help to evaluate your asset. The matter is not only to operate them, but to choose the right tool for specific applications
• The earlier noise is considered, the better!
November 11-14, 2014 Adipec
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