I am currently on a construction project for a tank farm situated approx 50m from the sea shore. Due to the nature of the proximity of the site to the sea, the atmosphere is very salty therefore corrosion of structural steel members is very imminent.
I am currently faced with the challenge of recommending to my management, the type of paint to be used for the steel members. I took 2 steel sample and applied the following paint types on each sample:
1. Gloss Paint applied over Red Oxide paint
2. Epoxy paint
1. Gloss paint applied over Red Oxide paint: after preparing the steel surfaces and application of these paints, I left them exposed for 2 weeks.
Cost Implication of using gloss paint with red oxide paint undercoat:
2 Coats of Red oxide as under coat : 1m2 @ $30/m2 = $30
1 Coat of gloss paint as final coat : 1m2 @ $20/m2 = $20
Labor for painting(undercoat & final):1m2 @ $3/m2 = $3
TOTAL COST PER M2 FOR GLOSS PAINT OPTION = $ 53
2. Epoxy paint : after preparing the steel surfaces and application of this paints, I left them exposed for 2 weeks.
Cost Implication of using epoxy paint:
2 Coats of epoxy paint : 1m2 @ $54/m2 = $54
Cost of thinner(to be mixed with epoxy paint) required per m2 : 1m2 @ $15/m2 = $15
Labor for painting:1m2 @ $3/m2 = $3
TOTAL COST PER M2 FOR EPOXY PAINT OPTION = $ 72
Analysis and findings
At the expiration of 2 weeks, it was discovered that the steel members coated with gloss paint were completely corroded while the surfaces coated with epoxy paint were still intact.
It was discovered that epoxy paints, when used in the terrain, could last for close to a year before it is repainted.
Conclusion and recommendation
From the cost analysis, the establishment cost of epoxy paint is higher but the running / maintenance cost will be cheaper in the long run since repainting will be carried out every 9 months as against gloss paint that will not withstand the terrain for 2 weeks.
I will recommend the use of Epoxy paint to my Management.
References:
1. Chapter 2, Skills and Knowledge of Cost Engineering. 5th Edition Revised.
2. GAO Cost Estimating and Assessment Guide. Best Practices for developing and managing capital Program Costs
OK, I will accept this one, provided that you understand that you missed a lot of the steps shown on page 27 of your engineering economy, table 1-1.
ReplyDeleteIf I were in your shoes, for reporting to management and for tracking purposes, I would break it down on a cost per day basis. Cost per meter really doesn't make the impact on management that using a cost per day would...
BR,
Dr. PDG, Jakarta