Coating considerations
for
Asset Protection
RINA Conference London
Marine Renewable & Offshore Wind Energy
21st - 23rd April 2010
Alan Guy / Rodney Towers
Safinah Limited
Offshore Wind Energy UK
UK Round 3 Wind farm zones
UK target 2020
15% of energy from renewables
Estimated that the UK has 33%
wind resources in Europe
Offshore to be primary expansion
zone. Wind is more constant and
predictable
Jan 2010
UK govt awards Round 3 wind
farm zones / 9 successful bidders
Source: BWEA
£75bn programme for offshore
wind farm projects
Offshore Wind Energy UK
MW Capacity Plan
MW Capacity
Operational
2010
( Feb )
2015
2020
688
Under construction &
planned
6,000
Zones awarded
Number of turbine
towers ( est )
33,000
228
2,000
± 11,000
Source RenewableUK
Total Operational Capacity
10 year plan
40,000 MW
Largest Offshore Capacity Plan in Europe
This is a major growth business sector
Offshore Wind Towers
Painting Offshore Wind Towers
Typical 3 MW Tower structure
Painting area
per tower
Painting cost
per tower
EP / PU multi layer @ € 5 / m2
Total cost Paint + Application
up to € 25 / m2 *
* Source JPCL / Muhlberg March 2010
External
m2
Internal
m2
Total
m2
1250
1250
2500
€ 6250
€ 6250
€ 12,500
€ 31,250
€ 31,250
€ 60 – 70,000
per tower
Offshore Wind Towers
Structural protection in relation to project costs
Typical Wind Tower Structure
Installation cost per MW
Installation cost per tower / 3MW
€ 3.3 mill
€ 10 mill
Painting cost ( P+A ) per tower
Paint + Application
€ 60 – 70,000
as % tower installation cost
Factory painting + site erection painting
0.6 – 0.7%
˂ less than 1% of installed cost
Offshore Wind Towers
Structural protection in relation to project costs
Overview
Tower structures
No. of Tower structures
Painting areas & costs
2010
2015
2020
228
2,000
11,000
0.57 mill m2
5 mill m2
27.5 mill m2
€14-16 mill
€120-140 mill
€ 660-770 mill
( Feb )
Painting areas
2500 m2 per
100m tower
Painting costs
Paint + Application
€ 60 – 70,000 per tower
If the build specification fails to perform
failure repetition can multiply by the number of towers in the field
Offshore Wind Tower Fields
offshore repairs
Coatings
unfortunately
can fail
Offshore Wind Tower Fields
offshore repairs
Cost Problem
Access to
offshore location
...not by road
....but
... by boat or barge
Offshore Wind Tower Fields
offshore repairs
Cost Problem
Access to repair the coated surface
Staging difficult to erect & dismantle
Offshore Wind Towers
The coating repair cost multiplier
Operational cost problem
likely to be out of proportion
Coating repairs
repeat
repeat
repeat
Offshore Wind Towers
offshore repair costs
Tower structures
2015
2020
228
2,000
11,000
0.57 mill m2
5 mill m2
27.5 mill m2
Paint + Application
€ 60 – 70,000 per tower
€14-16 mill
€120-140 mill
€ 660-770 mill
Assume 3% area failure
17,100 m2
150,000 m2
825,000 m2
Offshore repair cost
up to €1000/ m2
€ 17 mill
€ 150 mill
€ 825 mill
No. of Tower structures
2010
( Feb )
Total Painting area
2500 m2 per
100m tower
Total Painting cost
To repair only 3% area failure
could cost more than the total initial cost of painting
Coating Breakdown
Coating performance failures can occur because of
one or more of the following:
–
–
–
–
–
–
–
–
–
Design
Product specification/selection
Product quality
Management processes
Preparation/application
Maintenance
Repairs
Climate/environmental control
Worker skill
Product quality is rarely the cause of failure
Coating breakdown
problems for Asset Owner / Field Manager
Design, application
Specification ?
System selection ?
Application issues ?
Coating breakdown
problems for Asset Owner / Field Manager
Bad spray application
Sharp edges
Photos
Stress cracking in dry film
ABS, Houston
Considerations
for achieving long term coating performance
Purpose of coating system
Adopt the Functional Specification concept in design phase
Key point – performance 15 - 20 years or 35 - 40 years
Choose between
multi layer 3 – 5 coat epoxy / p/urethane system
thermally sprayed Zn/Al + sealer/epoxy topcoats
‘green’ product 2–3 coat solvent free epoxy system
Asset Owner / Field Manager
undertake independent technical evaluation of Paint Specification in
Contract proposal prior to Contract agreement
Offshore Wind Towers
three different environmental zones
Upper section - atmospheric
blades, turbine, housings & structure
Coating - durable, anti-corrosive
Lower section – splash / tidal
tower structure
Coating - durable, anti-corrosive
Bottom section– tidal/immersed/buried
tower structure
Coating - anti-corrosive, anti-fouling
Splash zone is the most critical
Offshore Wind Towers
Coating selection
Structures
similar to rigs, platforms and ships
Difference
unmanned
difficult to monitor/assess
Requirements
long term performance
suitable for fabrication process
suitable for range of environment
ease of repair
Needs
care in selection
quality application
Offshore Wind Towers
Coating selection
Principal methodology
ISO 12944-2
Defines corrosion category of site by rate of
steel loss
Zone
mm / yr
Splash
0.4
Tidal
0.25
Immersed
0.2
Combine category with required durability to
select generic coating schemes
– Non-immersed areas
– Immersed areas
C5-M applies
Im-2 applies
– ISO 20340 further defines requirements for
high durability systems
Offshore Wind Towers
Coating selection
Generic 15 year maintenance free systems
Coastal / offshore areas
with high salinity
sea
or brackish water
C5 Category
Im-2 Category
3-6 coats EP + PU
Total 300-500 microns
1-2 coats of solvent free EP
Total 800 microns
3-5 coats Zinc silicate + EP + PU
Total 300-400 microns
2-3 coats high solids EP
Total 800 microns
1-2 coats solvent free EP
Total 800 microns
2 coats glass flake EP
Total 1000 microns
schemes selected should have proven track records in the field
Offshore Wind Towers
Coating system for 30-40 years protection
Metallization has now achieved 30 – 40 years low
maintenance protection on offshore oil & gas structures
The cost and application speed for systems which include this process
are now close to or the same as for multi layer organic coating systems
The reasons are a combination of
New alloy materials
New technology spray equipment
Contractors improved ability to control the application environment
The current trend in Europe is to
thermally spray Zn / Al (first coat) 60 – 100 mic dft
+ sealer coat
+ 2 x EP topcoats
Full exterior surface and internally 6-8 m up from bottom
Painting Wind Towers
the importance of quality application
The application contractor controls about 75-85% of the cost
The importance of good application is fundamental for success
Best Quality Application requires
Specified Standards of secondary surface preparation
for steel & appropriate QC
Trained and skilful spray painting personnel
Applicators to conduct own DFT & QC work for multi
layer coating systems
Applicators to have control over environmental
conditions during the application process
Painting Wind Towers
for long term coating performance
Optimum approach
Purpose built
Wind Tower coating factory
Photo Muehlhan
Herning, Denmark
Painting Wind Towers
for long term coating performance
Series of blasting & coating cells
Auto blasting / more consistent
Rz and surface cleanliness
Some robot painting / internals
Two component spray
equipment
Dust free environment
Climate & temperature
regulation
Relative Humidity control
Photo Muehlhan GmbH
Painting Wind Towers
for long term coating performance
Spray application
epoxy / p/urethane multi layer
systems or topcoats
Photo Muehlhan GmbH
Painting Wind Towers
for long term coating performance
Thermal spraying
Zn / Al alloy
metallization
Photo
Muehlhan GmbH
Painting Wind Towers
for long term coating performance
Finish painting internal areas
Photo
Muehlhan GmbH
Wave & Tidal devices
Prototype design - testing – scaling up
Some differing environmental conditions
But same considerations for long term coating performance
Offshore Marine Renewables
impact of fouling
Wind Towers
will occur but impact on power
generation and coating performance
generally small
will be confined to tidal & immersed
areas
Wave & Tidal devices
Impact could be significant. Issues may be
how to minimise fouling adhesion
differences between exposed surfaces
steel & composite materials
static or moving
possible impact of greater hydrodynamic
loads on tethered devices from fouling
build up
Offshore Marine Renewables
tidal devices
In locations of ‘useful’ tidal range and flow,
abrasion resistance of coatings and materials may be an issue
Coating Considerations
for Asset Protection & Structural Integrity
Coating product quality failures are unusual. Specification failures are not
Three recommended actions for Client / Asset Owner / Field Manager
which can reduce risk
1. Apply the Functional Specification approach
Coating system suitability for performance requirement
Coating system suitability for the application process
Coating system suitability for the field environment
Coating system suitability for repair & maintenance
2. Make an independent technical evaluation of coating specification within
design phase and prior to Build Contract
3. Audit the coating process independently during construction phase
Post ISO 9000 wrong coating specification cases have doubled ! *
* Source JPCL / K.Muhlberg Mar 2010
Unmanned structures
...deserve wise protection !
Sources & References
Sources of info & Photos
NaREC, Blyth, Northumberland
EMEC, Stromness, Orkney
Muehlhan GmbH, Hamburg
ABS, Houston
Papers
K.Muhlberg / JPCL March 2010
‘ Corrosion Protection of Offshore Wind Turbines’
A. Momber / JPCL Apr 2008 & Apr 2009
‘ Investigating Corrosion Protection of Offshore Wind Towers Parts 1 & 2 ’
‘ Thank you ‘