Calculation of sqm for zinc coating

Question

Hello! I am currently working with openlca and ecoinvent 3.4 database. I have to apply a zinc coating to a tube of steel with lateral area of 2.07 m^2, 6 m of height and 78 kg. At the beginning I used directly 2.07 m^2 as amount using the process called "zinc coating coil" but my final impact results were too unbalanced. Then I read in the description of the coating process this phrase: "This module is applicable, if continuous zinc coating (galvanising) of hot or cold rolled strip- or wire-coils has to be inventoried. Data given per tonne of coated product are transformed by dividing them by the mean surface area of 64 m2/t."

To obtain the right m^2 is it correct to use make the following calculations: 78/1000/64? Thank you for your answer!

Answer 1

The process description says further "corresponding to ca. 4.2 mm thickness" (of zinc). I am checking zinc coating, coils | zinc coat, coils | APOS, U RER in ei 3.7 but this is probably the same in ei 3.4. The product is zinc coating by galvanizing for 1 m², thus I think the total mass of your product does not matter. Rather you should consider the thickness of the zinc layer in your case (which you could maybe calculate from weight difference before and after the process, divided by the total area). If the zinc layer is thinner in your case, e.g. 3mm, multiply everything by 3/4.2.

Hth, Andreas