What is a safety glass stamp (tempering stamp) and why is it important?

A safety glass stamp (tempering stamp) is a permanent marking that is applied to the glass during production. It is a ceramic marking baked into the glass, so it cannot be removed. It is used on tempered glass, laminated safety glass and tempered painted glass, among others, and shows that the glass is safety glass.

What does a safety glass stamp show?

The stamp shows that the glass has been made according to the applicable standard; for tempered glass this is the European standard EN 12150-1. A stamp usually includes:

• a statement that the glass is safety glass
• a reference to the standard (for example EN 12150-1)
• an identification of the manufacturer or supplier

This makes the glass traceable and recognisable as safety glass.

Why is a safety glass stamp important?

Without a stamp, users, installers and inspectors cannot see whether the glass really is safety glass. In some situations, that creates a risk.

A stamp is particularly important for applications such as:

• shower doors and shower enclosures
• balustrades and partitions
• doors and glass at impact height
• glass in public or commercial buildings

What happens if safety glass has no stamp?

Safety glass without a stamp can lead to:

• uncertainty about whether the glass really is safety glass
• rejection during an inspection or project handover
• discussions about liability in case of damage or injury

After damage or an incident, it can be hard to prove that the glass meets the required standards if there is no stamp.

Is a safety glass stamp mandatory?

In many applications a stamp is not explicitly mandatory, but it is strongly recommended. The stamp is your proof that the glass has been made according to the right standard. Where safety plays an important role, including a stamp is standard practice.

Where is the stamp placed?

The stamp is usually placed in a corner of the glass, so that it stays visible but is as unobtrusive as possible. The exact position can vary per product or application.

When would you leave the stamp out?

Sometimes you may prefer not to have a stamp, for example for aesthetic reasons, because the stamp is visible in a corner of the glass. This mainly applies to:

• tempered mirrors or glass in furniture, such as glass shelves
• decorative applications and design objects, such as table tops
• picture frames or displays where the glass should look completely “invisible”

Keep in mind that without a stamp it is not visually verifiable that the glass is safety glass. This can cause uncertainty about the glass specifications during an inspection, at handover or after damage.

Leaving out the stamp is always the customer’s own decision. Where safety, regulations or liability matter, we strongly recommend including a stamp.

The stamp is permanent and cannot be changed afterwards

Because the stamp is applied during production, it is permanent. It cannot be removed without damaging or replacing the glass.

You choose whether you want a stamp when you order. Once the order has been placed, this choice cannot be changed, because the glass is produced to your specification. So check carefully beforehand whether you want a stamp, especially where both appearance and safety matter.