India’s leading glass portal
  • Home
  • About Glazette
  •                                       
  •             
  • Register
  • |
  • Sign-in
G+FacebookTwitterYoutubeRSSLinked In
  • FEATURES
  • VIDEOS
  • WEBINARS
  • GLASS RESOURCES
    • Processing Glass
      • Tempered Glass
      • Heat Strengthened Glass
      • Laminated Glass
      • Insulated Glass
      • Ceramic Printed Glass
      • Heat Soaked Glass
      • Fire Resistant Glass
      • Low-emission GLass
      • Reflective glass
    • History of Glass making
      • Disc process
      • Glass History
    • Float Glass
      • Float Glass Production Process
    • Glass Types
      • Bullet Proof Glass
      • Self-Cleaning Glass
      • Body-tinted Glass
      • Etched Glass
      • Acid-Etched Glass
      • Low-emission GLass
      • Sandblasted Glass
      • Liquid Crystal Glass
      • Photovoltaic Glass
      • Bent Glass
      • Enamelled Glass
      • Electrically Heated Glass
      • Electrochromic Glass
      • Electrochromic Vacuum Glass
      • Satin Glass
      • Burmese Glass
      • Annealed Glass
      • Crown Glass
      • Dichroic glass
      • Tiffany Glass
      • Fused glass
      • Wired Glass
      • Chemically Strengthened Glass
      • Patterned glass
      • Frosted glass
      • Smart Glass
      • Spandrel Glass
      • Foam Glass
      • Anti-Fogging Glass
      • Hurricane-Resistant Glass / Hurricane Proof Glass
    • Tools & Calculators
  • CONTESTS
    • Transparence 2014
    • World Habitat Day 2011
      • Quiz
      • My Green City
      • Wall Poster
    • Bio Diversity 2011
    • Creativity & Innovation
    • Green Building Contest
    • NASA Utopia 10
      • Express Yourself
      • Beyond the Break
      • May I Help You
      • La Dicte
      • Caught in the Web
      • Style Icon
      • Twitter
  • JOBS
    • Search Jobs
    • Add Jobs
  • MEMBERS
    • Membership Benefits
    • Become a Member
    • Women's Day 2012 Featured Members
    • Associate Club Members
  • SEARCH
    • Custom Search
    • Search for Member
    • Advanced Member Search
Heat Strengthened Glass

Overview of Heat Strengthened Glass:

Heat strengthened glass is similar to tempered glass except that the cooling is done at a much slower pace. Annealed glass is heated to approximately 650-700 º C, but the cooling process is slower than that for tempered glass. Heat strengthened glass is about twice as strong as annealed glass of the same size and thickness. Heat strengthened glass is a semi tempered glass which retains the normal properties of ordinary float glass. Heat Strengthened glass has been strengthened thermally by inducing a surface compression of 6000 to 9000 psi as compared to a range of 11000 to 20000 psi in case of fully tempered glass. Heat strengthening adds strength to the glass while limiting the change in its breakage characteristics. The cooling process places the surfaces of the glass in a state of high compression and the central core in a state of compensating tension.

Heat Strengthening Process:
HS glass - in which heats the glass to a uniform temperature of approximately 650º C to 700 º C in an electrically heated horizontal furnace. Ceramic rolls convey the glass through these furnaces at speeds regulated to ensure temperature uniformity and minimal optical distortions. The heat strengthened process parallels the traditional process of glass tempering, except that the cooling cycle is less rapid. However, the heating temperature remains the same for both processes. The residual stress on the edge and the glass surface differ in both cases with tempered glass having a higher level of stress. Due to the relatively lower rate of cooling during the strengthening process, heat strengthened glass develops less stress as compared to fully tempered glass. The process increases the mechanical and thermal strength of heat strengthened glass, making it twice as tough as annealed glass.


Characteristics of Heat Strengthened Glass:

Heat-strengthened glass provides necessary resistance to thermal stress associated with high performance glazing materials such as tinted glass, reflective glass and Low-E glass. It also provides necessary resistance to heat building up when using spandrels glass.
When producing Heat strengthened laminated glass as compared to Tempered Laminated glass, Heat-strengthened glass allows the interlayer to laminated glass to adhere more evenly because of a flatter finish surface.
Heat-strengthened glass with its flatter surface also results in the facade having less optical distortions.
With the exception of strength and breakage characteristic, heat-strengthened glass retains the normal properties of annealed glass including chemical resistance, hardness, expansion and deflection.
This glass is difficult to break compared to ordinary annealed glass but unlike toughened safety glass it breaks typically edge to edge and fragments.

Breakage Pattern of Heat Strengthened Glass

 

Properties of HS Glass:

Properties Heat-Strengthened Glass
Thermal Shock Resistance Up to 130°C
Mechanical Strength Two times stronger than annealed glass
Fragmentation Knife Edges
Tensile Strength 40-55 MPa
Bending Strength 40 N/mm2
Design Stress for Architectural Purpose 17 MPa

 

Benefits of heat-strengthened glass:

 

Heat-strengthened glass differs from tempered glass in surface compression; its mechanical strength is about 1.6-2 times that of annealed glass.
Heat-strengthened glass has outstanding thermal stability, its flatness and light transmission is close to that of annealed glass and much better than that of tempered glass.
HS Glass is 3 times more resistant to thermal stress in comparison to normal annealed glass.
It can withstand temperature difference of 100°C (in range of 50°C to 150°C) compared to ordinary annealed glass which can withstand up to 40°C.
Heat strengthened glass is that it is far less susceptible to spontaneous breakage.

 



Applications of HS Glass:
 

 

Heat-strengthened glass continues to gain popularity and is often the choice of the design professionals for vertical vision spandrel areas and for laminated sloped glazing. Heat-strengthened glass is valued for its mechanical strength which is twice of normal annealed though half of fully tempered glass.
Heat strengthened glass has a comparatively flatter finish than fully tempered glass. It therefore has lesser optical distortions and so can be used in places where high optical quality is required.
It can be used for general glazing where additional strength or resistance to mechanical/thermal loads caused by certain tinted or coated glass. The glass can also be used in high wind load areas, but cannot be used in any safety glazing applications.
Heat-strengthened glass is widely used in laminated glass for additional strength, such as in overhead and sloped glazing.

 
Glazette
Thought Leaders

Rajan Govind
Glass Academy Board Member
& Facade Specialist, BES Consultants


M Anand
Senior Counsellor – CII GBC
R Subramanian
Chairman – Glazing Society of India

Sriram N
IGBC accredited Professional & GRIHA Trainer

Deepa Sathiaram
Founder – Director, EN3 LEED Professional

S Srinivas
Principle Counsellor - IGBC LEED accredited Professional

Quick Search
Members (13136)
Become a Member of India's Leading Glass Portal - Join Now!

Architects  (4770)
Builders  (556)
Dealers  (479)
Fabricators  (874)
Facade Consultants  (324)
Guest Users  (1530)
HVAC Consultants  (80)
Interior Designers  (1647)
Processors  (138)
Students  (2649)
Window Makers  (89)


Newsletter Sign-up


Subscribe to get updates on glass, architecture,green movement, design trends in glass, events for students
Glass Knowledge Bank
Tempered Glass
Heat Strengthened Glass
Laminated Glass
Insulated Glass
Ceramic Printed Glass
Heat Soaked Glass
Fire Resistant Glass
Low-emission GLass
Reflective glass
Disc process
Glass History
Float Glass Production
Bullet Proof Glass
Self-Cleaning Glass
Body-tinted Glass
Etched Glass
Acid-Etched Glass
Low-emission GLass
Enamelled Glass
Photovoltaic Glass
Sandblasted Glass
Bent Glass
Smart Glass
Tiffany Glass
Crown Glass
Wired Glass
Green Buildings
Electrochromic Glass
Sustainable Design
Liquid Crystal Glass
Spandrel Glass
Fire Resistant Glass
Ceramic Printed Glass
Electrically Heated Glass
Glass History
LEED | BEE
© The Glass Portal with Resources on Glass in Green and Sustainable Architecture, Interior Design and Innovations in Glass.
No part of this site should be used in any other media without prior permission. Terms of Use and Legal Disclaimer   |   Contact Site Admin   |   Sitemap
Website Design and Online Marketing: Niyati