CAT I vs CAT II Safety Backing — What the Inspector Checks

Short answer: CAT I and CAT II are defined performance classes describing how well a backing retains glass fragments after impact, tested against criteria in standards such as EN 12600 and ANSI Z97.1. CAT II is the higher class and the common call for public and commercial restrooms. "Safety film applied" is a description of a material, not a class, and will not satisfy a reviewer.

What the classes measure

Both classes are about one thing: after the glass breaks, does the sheet stay together. The test drops a defined impactor onto a mounted panel from a set height and examines what happens to the fragments. A panel passes a class if the breakage pattern stays within the limits that class defines.

That is worth restating because it is frequently confused with strength. Neither class makes the mirror harder to break. They describe the *consequence* of breaking.

	CAT I	CAT II
Tested to	Criteria in EN 12600 / ANSI Z97.1	Same standards, higher impact class
Retains fragments after impact	Yes, to the lower threshold	Yes, to the higher threshold
Typical call	Lower-traffic commercial, back-of-house	Public restrooms, transit, schools, healthcare
Certificate	Per batch, from the testing laboratory	Per batch, from the testing laboratory

Why "safety film applied" fails review

Film is a material. A class is a tested outcome. Two panels can both have film on the back and land in different classes, or in no class at all, depending on the film, the adhesive, the glass thickness and how the assembly was made.

A reviewer asking for the class is asking for a document with a batch reference on it. A supplier answering with a material name has not answered the question. If the specification says CAT II, the acceptable response is a classification certificate for the batch you are buying — not a data sheet for the film.

Tempering is a different question

This trips up specifications regularly, so it is worth being explicit:

• Tempering changes how the glass breaks — into blunt granules instead of shards.
• Backing holds the pieces in place after they break, whatever shape they are.

They solve different problems and one does not substitute for the other. There is also a manufacturing constraint that matters here: mirror glass cannot be tempered after silvering, so a tempered mirror has to be tempered first and silvered second. Any supplier offering tempered mirror should be able to confirm that sequence without hesitating.

Where each class belongs

The class follows the impact environment, not the room type. A back-of-house corridor in a hotel and a guest bathroom in the same hotel are different environments.

CAT II is the default call anywhere the public has unsupervised access and a mobility aid, a trolley or a crowd can reach the glass: transit restrooms, schools, stadiums, healthcare corridors. Our CAT II reinforced-backing project mirror is built for that specification in horizontal formats.

CAT I is appropriate where access is controlled and impact is incidental rather than expected. The CAT I vertical commercial mirror covers that case at lower cost, and specifying it honestly where it fits leaves budget for the fixings, which is usually where the real risk sits.

Specifying the range

The ADA, convex and safety-backed range covers both classes alongside tilt mirrors and copper-free glass for wet areas. Send the impact environment and the panel sizes; we will come back with the class recommendation and a price within 24 hours.