Suggested coating thickness shall be in the range of 60-120 μm (microns).
The equation giving the powder consumption versus coating thickness is:

Consumption (g/m2) = Coating Thickness (μm) x Specific Weight (g/cm3) (Powder specific weight varies between 1,4-1,7 g/cm3 depending the chemistry and shade of the powder coating).

Usual environment categories regarding the corrosion effect onto the coatings are:

Environment 1: Indoor use, humidity less than 60 % (low danger).
Environment 2: Indoor use, high temperature and humidity or Outdoor use away from sea, industries (medium danger).
Environment 3: Outdoor use urban areas or industrial areas or seaside areas (high danger).
Environment 4: Outdoor use exposition in continuous high humidity in industrial areas, heavily polluted (very high danger).

Polyester powder coatings are suitable for environments 1,2,3,4. The lifetime of polyester powder coatings depends on:

A) Environment surrounding the coated object.

Durability against sunlight
a) Accelerated weathering test DIN 54004 where the coated object is being subjected in cabin under artificial UV light and humidity coming from evaporation of water, for a period of 250 – 1000 hours. At the end of the trial the specimens should keep minimum 50% of initial gloss and shade (Solarbox or QUV equipment).
b) Florida test ISO 2810 where the coated object is being subjected in natural wheathering for 3 year period. At the end of the trial the specimens should keep minimum 50% of initial gloss and also no chalking effect is accepted. The color difference shouldn't be appreciable as well.

Durability against temperature

Temperature test, the specimen remain 120^οC for 1000 hours without yellowing or obvious changing of color.

Durability against corrosion
a) Saltspray test ISO 9227 where the coated object is being subjected for 1000 hours in cabin simulating humidity, temperature, salt environment. b) Humidity cabinet test DIN 50017 where the coated object is being subjected for 1000 hours in cabin simulating humidity and temperature.

c) Kesternich test ISO 3231 wher the coated object is being subjected in SO₂ environment for 24 cycles continuously.

Durability against chemical substances as well as oxygen permeability
You may find the relative list at the end of this page.

B) Metal type and reccomended pretreatment of powder coating.

Ferrous and Steel: phosphatizing (ferrous or zinc) or sandblasting.
Galvanized Steel: phospate or chromate coating.

Cast Steel: sandblasting and primer.
Aluminium: chromate or titanium/zirconium conversion.
Cast Aluminium: chromate conversion with additive.
Zamak: chromate or phosphate conversion.
Brass and Copper: chromate conversion or sandblasting.

C) Application parameters of powder coating:
-Curing of the powder coating (hardening) inside the curing oven.
-Coating thickness.
-Coverage percentage of the coating of the object.