What discussion points favor galvanized steel over painted or coated structural Coker steel? Can coated or painted steel give similar service life? Are there any detrimental results from using painted or coated steel structure members?
This probably should be bounced off workshop of Refinery Corrosion Engrs at coking refineries. Coking Units represent the largest number and broadest types of corrosive actions – many levels above other units because of Cyclic Stress, Stress Corrosion Cracking, EletroChemical Corrosion and many other forms of metal on metal impacts. Add to that some the highest thermal cycles of 70F to 900F every coker cycle and just about every form of protection is needed.
Even though its dated (2000) – there is good ASTMPDF on Effects & Impacts Corrosion (shows ~12 catagories) @ http://www.asminternational.org/content/ASM/StoreFiles/06691G_Chapter_1.pdf
and I understand that NACE had Corrosion Conf 2012 that had lot papers on galvanized steel / coatings so toggle that or have your plant metallurgist do it for best results.
One other things that come into play is lot external environments some these refinery & coking units face – I was stationed Billings Montana Refinery & the swing from -40F (no wind chill just temp!) to +80F in 24 hr period often made the conditions outside pipe & structures worse anything inside them.
Best to reconcile that there is no magic bullet where one process provides cure but effective use of everything and right application for particular problem is best fit.