Tempered glass must have the 3C mark! How to minimize the risk of self-detonation?

Tempered glass must carry the 3C certification mark, which is a national compulsory safety certification, but the sign itself cannot prevent self-destruct. The following is the ultimate solution to reduce the risk of self-detonation, combining technical principles with practical guides:

1. The truth and counterfeiting method of the 3C mark

1. The core significance of the 3C logo

Standard bottom line: No 3C = non-tempered glass

Basic guarantee: represents the surface stress ≥ of the glass 90MPa (only the foundation strength meets the standard).

No self-detonation prevention: 3C does not detect impurity content, and the self-detonation rate has nothing to do with certification

2. Distinguish between true and false 3Cs (three-step counterfeiting method).

Inspection method	True 3C features	Fake 3C flaw
Scratch test	The logo is laser etched and cannot be scraped off	Ink printing, scrape off
Number check	The factory number can be found on the official website	The number does not exist or corresponds to a non-glass factory
Purple light illuminated	The logo contains anti-counterfeiting fluorescent fibers	No fluorescence reaction

Basis for rights protection: According to the "Regulations on the Management of Building Safety Glass", the use of non-3C tempered glass can be reported to 12315, and the maximum fine will be confiscated and a fine of 3 times will be imposed.

2. The culprit of self-detonation and scientific prevention and control

1. The root cause of self-destruction

Nickel sulfide (NiS) impurities: "glass cancer" in glass, high-temperature phase change volume expansion 4%

Elemental silica particles: Local stress explosion caused by poor coefficient of thermal expansion 

Critical size: Impurity particles with a diameter of > 0.04mm can trigger self-detonation

2. Distribution law of self-detonation rate

Glass type	Plain tempered glass	Homogeneous tempered glass	Ultra-white glass tempered
Self-destruct rate	3‰~5‰	0.1‰~0.3‰	＜0.01‰
Self-destruct time	2~5 years after installation	It was detonated before installation	Almost never happens
Cost increase	-	+8~12 yuan/㎡	+100~150 yuan/㎡

Data source: China Institute of Building Materials 100,000 square meters curtain wall tracking statistics (2015-2023).



3. Six-fold explosion-proof technical scheme

1. Raw material upgrade: ultra-white glass

Principle: The raw material is pickled to remove iron, and the residual amount of NiS < 0.1ppm (5~10ppm for ordinary glass).</b11>

Identification: Light blue when viewed from the side (ordinary glass is greenish)

Applicable: high-risk areas such as high-rise curtain walls, lighting roofs, guardrails, etc

2. Homogenization treatment (HST): detonation in advance

Process: 290°C±10°C for 2 hours → promote the self-detonation of NiS phase change

Acceptance: The manufacturer is required to provide a homogeneous furnace temperature curve record (fluctuation of the insulation section ≤5°C). HST laser marking (non-ink printing) on the corners of the glass

3. Precise stress control

Parameter	High risk value	Safety value	Detection tools
Surface stress	＞120MPa	90~110MPa	Surface stress gauge
Stress layer depth	＜0.18h*	0.20h~0.25h	Stress layer detector
Stress unevenness	＞20MPa	＜15MPa	Polarized light analyzer

*h is the thickness of the glass

4. Edge strengthening treatment

Fine grinding chamfer: R≥0.5mm fillet (reduce stress concentration).

Coating protection: Silane impregnation sprayed on the edges (waterproof vapor erosion microcracks)

5. Key points for installing pit avoidance

Block matching: EPDM rubber pad with hardness 50±5 Shore A (PVC hard block is prohibited).

Clearance reservation: The clearance between glass and notch is ≥ 5mm (thermal expansion buffer space).

No hard contact: the frame and the glass must be filled with neutral silicone structural glue

6. Intelligent monitoring system

Stress patch: photochromic film attached to the corner of the glass (stress over-limit reddening warning)

Acoustic emission monitoring: captures the ultrasonic signal of glass crack propagation (accuracy 0.01mm).



4. Consumer self-insurance list

1. The purchase contract specifies:

"Glass type: ultra-white homogeneous tempered, surface stress 100±10MPa, HST treatment record provided"

2. Acceptance toolkit:

Purple light (test 3C).

Polarizing Sheet (Stress Spot)

Vernier caliper (measured chamfer R≥0.5mm).

3. Warranty terms:

"Self-destruct free replacement, 10 years warranty period (only 2 years for ordinary projects)"

Final Conclusion:

3C is just the "birth certificate" of tempered glass, and ultra-white + homogenization treatment is the explosion-proof king bombing combination. In key parts such as high-rise curtain walls and sunrooms, upgrading ultra-white glass is equivalent to buying an "explosion-proof insurance" for the building - after all, the cost of glass self-detonation far exceeds this cost!