| |
|
Posted:
Sun 7th Feb 2010
|
Original Post |
User: craig
Status: ordinary
Joined:
Dec 2009
Total Posts: 0
|
does any one know of any concrete evidence that rockwool insulation can accelerate corrosion in marine environments? |
|
Report this topic
|
|
Posted:
Tue 9th Mar 2010
|
|
Reply #1 |
|
User: bobakid
Status: professional
Joined:
Mar 2009
Total Posts: 1
|
I have not seen any literature on this. However it would seem sensible that any material present which can act as a condensing surface, will increase the time of wetness. Hence it will affect the degree of corrosion.
Tech. Ed CM. |
|
Report this post
|
|
Posted:
Wed 17th Mar 2010
|
|
Reply #2 |
|
User: quinny
Status: professional
Joined:
Mar 2009
Total Posts: 1
|
Not mineral wool (Rockwook) on its own. You need to give more information with this question, such as:
What the piping/vessels are made from i.e. stainless steel?
What is the operating temperature of the insulated equipment?
What is the location, on an oil rig, open to the elements, or tucked away in an engine room of a ship?
|
|
Report this post
|
|
Posted:
Sat 20th Mar 2010
|
|
Reply #3 |
|
User: fyfecj
Status: professional
Joined:
Mar 2009
Total Posts: 6
|
It’s the materials ability whether its mineral wool or other to retain moister. It’s this retained moister, “and component temps” ,which accelerates corrosion and instigates the CUI phenomenon.
The operating and design temperature of the component will influence type of coating and type of Insulation system. The system would then be covered with a outer weather shield, again it’s the ability of the outer weather shield to mitigate water moister ingress that’s important.
A common reason for failure is foot traffic, “people stepping onto it”. This courses break at joints and any component interface allowing ingress to the system.
Worst case scenarios should be considered, assume your system will be compromised and specify an immersion grade coating. At temps -5:150c drain plugs are now been considered.
State oil produced a hand book for the Troll project this does go some way into explaining pitfalls in various systems.
|
|
Report this post
|
|
Posted:
Fri 30th Apr 2010
|
|
Reply #4 |
|
User: tony richards
Status: visitor
Joined:
Apr 2010
Total Posts: 1
|
CUI is not caused or accelerated solely by Rockwool insulation.
Major factors influencing CUI:
• Prevention of water ingress into the insulation system by adequately designed outer cladding – This is the first line of defence
(NO WATER = NO CORROSION)
• Adequate corrosion prevention treatment of the substrate – This is the last line of defence
• Operating temperature
Corrosion increases with temperature up to approx. 100ºC
• pH value of the insulation layer
pH levels <5 promotes vigorous corrosion
pH 7 - 10 corrosion significantly reduced
pH >10 corrosion potential further reduced
• Insulation type
Corrosion is possible under all types of insulation
Features which make Rockwool products the best choice when attempting to prevent CUI:
• Rockwool is water repellent –
o Standard grade offers a high level of water repellency due to its mineral oil content. For high levels of water repellency at elevated temperatures or to meet the demands of BP 172 Engineering Standard then WRG should be specified
• Rockwool is non-hygroscopic
o Rockwool does not absorb water from the air
• Rockwool is vapour permeable
o Any water which enters the system can escape
• Rockwool has a pH between 7 & 9
o Leached acids, especially pH<5 are highly corrosive
|
|
Report this post
|
