What is the minimum anodizing thickness for an exterior window?

For Grade AC 25 (Exterior Architectural), the minimum average thickness is 25 microns and the minimum local thickness is 20 microns (Table 1).

Which aluminium alloy is specified?

Aluminium alloys conforming to IS 733, such as Grade 6063 (HE9), are specified for these sections (Clause 3.1 & Table 2).

How is the quality of the anodic coating checked?

Key tests include measuring coating thickness (IS 6012), quality of sealing (IS 8688), and abrasion resistance (IS 5523) (Clause 6).

What do the different anodizing grades mean?

Grades like AC 25, AC 20, AC 15, and AC 10 define the minimum average coating thickness in microns, corresponding to different levels of durability and intended use (Table 1).

IS 12858

: 2002

Anodized Aluminium Sections for Doors, Windows and Ventilators

CurrentFrequently UsedSpecificationBIMArchitectural · Doors, Windows and Shutters

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This standard specifies the requirements for anodized wrought aluminium alloy extruded hollow and solid sections for use in the fabrication of doors, windows, ventilators, and partitions. It covers material composition, dimensional tolerances, and various grades of anodic coatings based on thickness and intended use (interior/exterior), along with the test methods to verify their quality.

Specifies dimensions, properties, and anodizing requirements for aluminium sections for doors, windows and ventilators.

Quick Reference Values

Min avg. coating thickness (Grade AC 25, exterior)25 micron

Min local coating thickness (Grade AC 25, exterior)20 micron

Min avg. coating thickness (Grade AC 15, interior)15 micron

Min avg. coating thickness (Grade AC 10, interior)10 micron

Max mass loss in sealing test (acid dissolution)20 mg/dm²

Applicable Aluminium Alloy Grade (e.g.)6063 (HE9) as per IS 733

Practical Notes

Always specify Grade AC 25 for exterior applications, especially in coastal or industrial areas, to prevent premature corrosion and chalking.

The quality of sealing is as important as the thickness. Insist on the sealing test (acid dissolution test) report from the supplier.

Visual uniformity of color and finish is important, but does not guarantee performance; physical test reports for thickness and sealing are mandatory for quality assurance.