Out of sight must not be out of mind

DEMM Engineering & Manufacturing - - CORROSION & COATINGS -

Cor­ro­sion af­fects all con­crete build­ings and struc­tures around the world and they de­te­ri­o­rate at vary­ing rates over time, de­pend­ing on the ma­te­rial used, the types of cor­ro­sive agents in the en­vi­ron­ment and the phys­i­cal pro­cesses and mech­a­nisms in­volved. Glob­ally, the es­ti­mated an­nual cost of con­crete cor­ro­sion to in­dus­try is bil­lions of dol­lars.

The smooth, shiny ap­pear­ance of tanks and pipework you might see at a man­u­fac­tur­ing fa­cil­ity or con­struc­tion site may seem pris­tine and safe, but of­ten un­der the sur­face is in­su­la­tion, wa­ter, a pro­tec­tive coat­ing and sig­nif­i­cant amounts of cor­ro­sion.

Cor­ro­sion Un­der In­su­la­tion (CUI) is a per­va­sive but in­sid­i­ous form of met­als cor­ro­sion. Most in­dus­trial or com­mer­cial fa­cil­ity – from the largest re­finer­ies and chem­i­cal plants to a lo­cal hos­pi­tal or neigh­bour­hood bak­ery – has in­su­lated equip­ment. There are many rea­sons equip­ment is in­su­lated, in­clud­ing en­ergy con­ser­va­tion, pro­duc­tion process sta­bil­ity or per­son­nel pro­tec­tion, whether the prod­uct in­side is hot, cold, or cy­cles be­tween tem­per­a­ture ex­tremes.

Wher­ever in­su­la­tion is used, there will be some amount of cor­ro­sion un­der it. Unchecked CUI can cause thin­ning of the metal wall of a pipe or ves­sel which may lead to cat­a­strophic per­fo­ra­tion or rup­ture. The ef­fects of which are in­creased where the ves­sel or pipe con­tains flammable or poi­sonous prod­uct un­der pres­sure.

In Aus­tralia, the yearly cost of as­set main­te­nance is es­ti­mated to be ap­prox­i­mately $32 bil­lion. Avoid­able cor­ro­sion dam­age, such as CUI, ac­counts for $8 bil­lion of this and con­tin­ues to have a ma­jor eco­nomic im­pact on in­dus­try and the wider com­mu­nity. Each year around the world there are hun­dreds of fail­ures and in­ci­dents – to vary­ing de­grees of sever­ity – caused by CUI.

It is im­por­tant that own­ers of high-value as­sets un­der­stand the cost im­pli­ca­tions of ig­nor­ing the ef­fects of cor­ro­sion un­der in­su­la­tion. Or­gan­i­sa­tions re­quire ef­fec­tively trained staff who have an un­der­stand­ing of the

nu­mer­ous types of cor­ro­sion that af­fect their in­dus­try and of the pre­ven­ta­tive and re­me­di­a­tion tech­nol­ogy avail­able.

As part of its char­ter, the Aus­tralasian Cor­ro­sion As­so­ci­a­tion ( ACA) presents a con­tin­ual pro­gram of tech­ni­cal sem­i­nars and train­ing cour­ses each year. In June 2018, the ACA is pre­sent­ing a se­ries of two- day tech­ni­cal work­shops deal­ing with CUI. The work­shops will be pre­sented by in­ter­na­tional CUI spe­cial­ist and con­sul­tant Peter Bock from Hous­ton, USA. Bock has more than thirty years’ ex­pe­ri­ence in el­e­vated tem­per­a­ture coat­ings and CUI and has pub­lished nu­mer­ous ar­ti­cles as well as spo­ken at NACE, SSPC, ICC and other na­tional and in­ter­na­tional con­fer­ences re­gard­ing CUI prob­lems and so­lu­tions.

To be held in Perth (19-20 June), Sydney (25-26 June) and New Ply­mouth (28-29 June), the work­shop is ded­i­cated to de­sign, spec­i­fi­ca­tion and in­spec­tion of cor­ro­sion con­trol sys­tems to prevent CUI in new or aged equip­ment and will cover top­ics such as the causes of CUI, cur­rent state- of-the-art CUI coat­ing sys­tems, in­spect­ing and eval­u­at­ing aged CUI in the field and ap­pro­pri­ate CUI re­pair coat­ing sys­tems.

In­dus­trial in­su­la­tion is a sys­tem com­posed of an outer pro­tec­tive jack­et­ing, one or more lay­ers of in­su­la­tion, and a pro­tec­tive coat­ing ap­plied to the metal sub­strate. Even after tak­ing ev­ery pre­cau­tion dur­ing the de­sign, con­struc­tion and op­er­a­tion of an as­set, ev­ery in­su­la­tion project will sooner or later be af­fected by CUI. And un­like “nor­mal” cor­ro­sion, CUI is hid­den un­der the in­su­la­tion and jack­et­ing and is not read­ily vis­i­ble – out of sight and too of­ten out of mind.

The high cost of re­place­ment in­su­la­tion, labour, and op­er­a­tional down­time time means that only a small per­cent­age in­su­lated area is ever opened up for vis­ual in­spec­tion. The rest of the area may be in­spected us­ing var­i­ous elec­tronic means, which may or may not give ac­cu­rate in­di­ca­tions of CUI. Parts of an in­su­lated area may not be vis­ually in­spected at all dur­ing the ex­pected 15 to 18 year ser­vice life of an as­set threat­ened by CUI.

Places are still avail­able for the work­shops and book­ings can be made via the ACA web­site un­til 25 May at www.cor­ro­sion.com.au/events. The full pro­gramme is avail­able through the web­site.

Newspapers in English

Newspapers from New Zealand

© PressReader. All rights reserved.