Thermal cracking mechanism and engineering response of single-piece fireproof glass

Introduction

As a key material for building exterior protection, the thermal cracking behavior of glass in fire directly affects the escape of personnel and the spread of fire. This article focuses on the thermal cracking mechanism of **single-piece fireproof glass (DFB)** and analyzes its fire-resistant nature.

1. The core driving force of thermal cracking: temperature difference stress

Research has confirmed (Xie, Keski-Rahkonen, etc.) that the fundamental cause of glass cracking is the critical thermal stress caused by **uneven heating:

Ordinary soda-lime glass: critical temperature difference is only **80~90℃

6mm tempered fireproof glass**: critical temperature difference **330~380℃

10mm tempered fireproof glass**: critical temperature difference **470~590℃

When the temperature difference between the exposed area (fired) and the shielded area (frame) of the glass exceeds the threshold in a fire, the tensile stress generated exceeds the tensile strength of the glass (usually 30~50MPa), which triggers the crack.

2. Key factors affecting cracking

| Edge processing quality | Mechanical polishing edge strength (78MPa) > rough grinding edge (56MPa), micro crack expansion strength attenuation 15%+ |

| Installation method | Point support stress concentration > frame installation; aluminum frame fire resistance > wooden frame |

| External intervention | Spray cooling will accelerate cracking when the glass temperature is > 250℃ |

| Glass type | Borosilicate glass (expansion coefficient 4×10⁻⁶/K) Thermal shock resistance Rolled soda-lime glass (9×10⁻⁶/K)

📌 Engineering warning: Fireproof glass design must reserve a safety factor K≥2.5 (refer to curtain wall specifications)

3. Technical breakthrough direction

1. Material upgrade

Borosilicate glass: low expansion + high softening point (800℃), the mainstream fire protection solution in Europe, and has broken through the bottleneck of mass production in China

Microcrystalline glass: zero expansion characteristics, temporarily limited to high-end special applications

2. Process control

Stress strengthening: surface compressive stress > 90MPa (national standard bottom line) can improve bending strength (formula: σ≈0.83σ tempering + 38)

Edge finishing: HF acid etching/mechanical polishing to reduce microcracks

3. Intelligent simulation application

Thermal-mechanical coupling simulation based on tools such as ANSYS can predict:

Stress distribution of different installation methods (see Figure 1)

Critical rupture time (error <10%)

Simulation confirms: The maximum tensile stress of framed glass is concentrated at the junction of the frame and shielding (31~32MPa)

IV. Engineering application suggestions

1. Carefully select glass type

Borosilicate monolithic fireproof glass (EN 12600/ANSI Z97.1 certification) is the first choice for high-end projects

Strictly control the discrete risk of soda-lime-silicon fireproof glass

2. Optimize installation design

Preferentially use a four-point support structure to reduce stress concentration

The shielding width needs to be verified by thermal simulation

3. Scenario protection

Avoid enabling the sprinkler system at high temperature (>250℃)

Conclusion

To understand the mechanism of thermal cracking, it is necessary to make breakthroughs in three dimensions: material nature (boron silicon > sodium calcium), process precision (edge ​​stress control), and installation science (thermal stress dispersion). With the large-scale mass production of domestic borosilicate glass and the popularization of digital simulation technology, the safety of fireproof glass will achieve a qualitative leap.

Custom toughened glass shower doors

For custom shower doors, safety-tempered glass is mandatory. It's stronger and shatters into small, blunt granules if broken, minimizing injury risk. Thickness selection is critical:

• 8mm: Most common, offers good stability.
• 6mm: Suitable for small doors or fixed panels.
• 10/12mm: Used for oversized or frameless doors, providing maximum solidity.

Optional features enhance function and aesthetics: laminated glass (extra safety), frosted/sandblasted glass (privacy), Low-E glass (heat retention).

Hole-drilling processes are vital:

1. Timing: All holes (for hinges, handles, etc.) MUST be drilled BEFORE tempering. Drilling after tempering causes instant shattering.
2. Precision: Holes require exact measurement and positioning based on design drawings, typically using specialized equipment (like CNC machines or waterjets) for accuracy.
3. Edge Treatment: Hole edges must be finely ground and polished to remove any chips or micro-cracks. This prevents stress concentration (which can cause spontaneous breakage) and ensures smooth, secure hardware installation.

In short: Choosing the correct, safe glass thickness and ensuring precise pre-tempering hole drilling and polishing are core to the safety and durability of custom shower doors.

Joy Shing Glass factory direct sales, wholesale purchase price is more favorable.

We can process glass as required, including size, shape, edge, corner, hole, groove, etc.

If you are looking for high-quality toughened glass, please contact us for quotation and sample.

Tempered Glass: The Safe & Strong Choice - Professional Manufacturing & Customization by Joy Shing Glass

     In modern architecture, home design, and industrial applications where aesthetics meet safety demands, ordinary glass often falls short. Tempered glass, renowned for its exceptional strength and unique safety properties, stands as the trusted solution. As experts in glass manufacturing, Joy Shing Glass breaks down the core advantages and types of tempered glass, delivering reliable, professional manufacturing services.

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1. Tempered Glass: More Than Just "Harder" Glass

Tempered glass (also known as toughened or safety glass) is created by subjecting high-quality float glass to a precisely controlled thermal process (heating to high temperatures followed by rapid, uniform cooling). This process builds powerful compressive stress layers within the glass, granting revolutionary properties:

Multiplied Strength:

Impact resistance 3-5 times higher than ordinary glass; bending strength 2-3 times higher.

Superior thermal shock resistance, withstanding temperature differentials up to 200-250°C, minimizing the risk of thermal breakage.

Safety First:

Core Advantage! Upon forceful impact, it shatters instantly into countless small, blunt, honeycomb-like granules, drastically reducing injury risks – making it true "safety glass".

Reliable & Durable:

High strength ensures better resistance to scratches, abrasion, and everyday impacts, extending its lifespan.

> Joy Shing Glass Key Note: Once tempered, glass cannot be cut, drilled, or reworked. All customization needs (size, shape, holes) must be finalized before the tempering process – a crucial step in our professional manufacturing flow.

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2. Tempered Glass Types for Diverse Needs (All Customizable by Joy Shing Glass)

We offer a diverse range of tempered glass products to meet your specific project requirements:

1、By Strength & Safety:

Fully Tempered Glass: The Standard Choice! High strength, excellent safety (granular breakage). Widely used in doors, windows, curtain walls, shower enclosures, furniture tops, appliance panels – anywhere requiring personal safety protection. (Joy Shing Glass Core Product).

Heat-Strengthened Glass: Moderate strength (~2x ordinary glass). Breaks into larger, sharper shards – not classified as safety glass. Suitable for applications needing high flatness, moderate strength, and no strict safety         requirements, like some interior partitions or curtain walls (designed to prevent total fallout). Always confirm safety needs!

2、By Shape:

Flat Tempered Glass: The most common type, available in various thicknesses.

Bent Tempered Glass: Specialized Craftsmanship! Glass is heated, bent to a specific curve, then tempered, combining strength with elegant form. Ideal for curved facades, architectural features, premium furniture, display cases. Joy Shing Glass utilizes advanced bending/tempering technology to accurately realize your design vision.

3、By Functional Combination (Often using Tempered Glass as Base):

Tempered Laminated Glass (PVB/SGP): Tempered glass + high-strength interlayer (e.g., PVB or SGP film). Even if shattered, fragments adhere to the interlayer, preventing penetration and fallout – top-tier safety! Essential for skylights, canopies, railings, banks, and high-risk curtain walls. Joy Shing Glass offers various interlayer options for different safety grades.

Tempered Insulated Glass Unit (IGU): Tempered glass + sealed dry air/gas cavity. Exceptional thermal insulation & soundproofing! The go-to for energy-efficient building windows and curtain walls. We provide Low-E coated tempered IGUs for enhanced energy savings.

Tempered Coated Glass (Solar Control / Low-E): Surface coating applied before tempering. Controls solar heat gain, reduces radiation, boosts energy efficiency. Key for high-performance building envelopes. Joy Shing Glass offers custom coating solutions.

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3. Joy Shing Glass: Your Professional Tempered Glass Manufacturing Partner

Choosing tempered glass means choosing safety and quality. Choosing Joy Shing Glass means you get:

✅ Professional Manufacturing: Utilizing advanced tempering furnaces and strict process control to ensure every piece meets strength standards and safety reliability.

✅ Flexible Customization: Whether standard flat, complex bent shapes, large formats, or special thicknesses – we produce based on your detailed drawings and specifications (all cutting, edging, hole drilling, notching done before tempering).

✅ Quality Certification: Products comply with relevant national safety standards (e.g., GB 15763.2), with critical products carrying CCC certification.

✅ Complete Solution Provider: We supply not only premium tempered glass but also laminated tempered, insulated tempered, coated tempered, and other composite products.

✅ Reliable Supply: Stable production capacity ensures your project timelines are met.

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4. Get Started: Infuse Safety & Strength into Your Project!

Tempered glass is ubiquitous: from the sturdy curtain walls of skyscrapers to the safe shower screens in your home, from elegant furniture tops to protective panels on devices. It's the indispensable safety cornerstone of modern design.

Planning a project? Need a reliable tempered glass solution?

> > Contact the Joy Shing Glass Team Today! <<

l We'll recommend the optimal tempered glass product or combination based on your specific application (architecture, home, furniture, appliances, specialty uses), safety level requirements, performance needs (strength, energy efficiency, soundproofing, aesthetics), and budget.

l Receive expert material selection advice and technical support.

l Benefit from fast responses to your quotes and customization requests.

Choose Joy Shing Glass for professionalism, safety, and guaranteed quality. Let's build stronger, safer spaces together!

Laminated Glass Impact Test-Safety Architectural Glass

Laminated Glass Impact Test:

The video shows the impact test of laminated glass. After the laminated glass is broken by impact, the fragments will be glued to the film to maintain the complete glass structure and avoid the danger caused by the glass breaking and falling off. It is a safe architectural glass. 

Laminated glass is widely used in building curtain walls, doors and windows, partitions, stairs, guardrails, skylights and other fields.

Laminated Glass

Application of Laminated Glass

As a professional laminated glass manufacturer, Joy Shing Glass supplies high-quality laminated glass and undergoes strict quality inspections, so you can buy it with confidence. We can customize and deep-process glass as required to provide an integrated glass solution for your construction project. 

If you are choosing a high-quality glass supplier, feel free to contact us for more details, samples, etc.

Advantages of tempered laminated glass ribs

What are the advantages of using tempered laminated glass for building facade glass ribs?

1. High transparency and beautiful appearance: Ultra clear tempered laminated glass is used, which has high transparency and reduces color distortion and green shadows.
2. Heat soak test: The tempered laminated glass has been heat soaked test, with high strength and load-bearing capacity, and the self-explosion rate is as low as 0.001
3. Interlayer design: The interlayer material maintains the integrity of the glass fragments when broken, prevents the fragments from scattering, and provides additional protection and safety.
4. Thermal stability: It has good thermal stability, can withstand high temperature changes without being easily broken, and is suitable for environments that need to withstand thermal stress.
5. Sound insulation: The tempered laminated glass ribs have good acoustic properties through interlayer design and tempering treatment, which reduces the transmission of noise and has a sound insulation effect.

Video of tempered laminated glass ribs

Joy Shing Glass can customize and deep-process glass according to requirements, providing you with integrated architectural glass solutions. If you are interested in this, please feel free to contact us.

Meeting Room Smart Film Glass Door

The meeting room smart film glass door can adjust the transparency of the glass, realize the free switching between open space and private space, and effectively separate the space. The smart film can be directly glued to the existing glass, which is more convenient to install and achieve better privacy protection effect.

In addition, smart film can also be used in restaurants, bathrooms, hotels, bedrooms, banks, offices and other places that require privacy protection.

Joy Shing Glass can provide an integrated smart privacy glass solution for your project. If you are interested in this, please feel free to contact us.

For more information about smart privacy glass, please refer to: switchable smart glass

Curved glass for spiral stairs.

Made of ultra clear curved glass with low iron content, beautiful and safe. Joy Shing Glass can customize and process glass according to requirements, including size, shape, thickness, edge, corner, hole, HST, laminated, etc. Provide you with an integrated glass staircase solution. If you have any needs, please feel free to contact us.