Why is semi-tempered glass not safety glass?

Semi-tempered glass (also known as heat-strengthened glass) is not a safety glass, and the core reason lies in itThe broken form does not meet the legal standards for safety glass.

1. Technical principle: what is unsafe

Comparison item	Semi-tempered glass	Tempered glass
Surface tension	24~60Mpa (only half of that of fully tempered glass)	>=90Mpa
Fragmented forms	Form elongated sharp fragments (similar to regular glass)	Honeycomb-shaped obtuse particles
Edge strength	The edges are fragile and prone to cracking from impact.	The edges have been reinforced and have strong impact resistance.

Key conclusions: Semi-tempered glass will still form sharp fragments after cracking, It may cause a risk of cuts to the human body and does not meet the core requirements of "cut prevention" of safety glass.

2. Regulatory standards: Semi-tempered glass is clearly excluded

China GB 15763.2-2005 "Safety glass for construction - Part 2: Tempered glass"

After the safety glass is broken, the number of fragments in any 50mm × 50mm area ≥ 40 (to prevent large fragments from being cut);

Semi-tempered glass fragments are usually 3~10 pieces/m² (much lower than safety standards).

International standard ISO 12543 and American ANSI Z97.1

All require safety glass to pass the "shotgun bag impact test" (semi-tempered glass cannot pass this test).

3. Application prohibition

The national standard "Technical Regulations for the Application of Architectural Glass" JGJ 113 clearly stipulates:

Safety glass must be used for seven types of parts that are easily touched by the human body (such as railings, floors, and bathrooms), and semi-tempered glass is prohibited.

Look, semi-tempered glass is indeed not very safe to use alone, and it cannot be regarded as safety glass.