PROPERTIES OF GLASS

MECHANICAL PROPERTIES

-brittle

-completely elastic to its ultimate tensile strength

-will fail at low stress due to presence of microscopic surface cracks

OPTICAL PROPERTIES

-transparent

-can be treated in different ways to reflect and absorb different degree of light

-tinted glass absorb more light than clear

-reflective coated glass reflects large portion of glass depending on the nature of coat , colour and thickness

THERMAL PROPERTIES

-solar gain through glass heats up inside of building

-cause running cost for aircons and heat loads

-different types of glass implemented such as insulating glass, reflective glass and tinted glass.

TYPES OPF NON-SAFETY GLASS

CLEAR SHEET GLASS

-used for normal glazing

-relative good quality with low cost

-smooth, hard finish and scratch resistant

-lack of superior quality of plate and float glasses

-lower quality sheet glass made by drawing upwards molten glass, a thin sheet

-cooled, rising sheet solidifies, then cut

-both surface less parallel

-lower quality of float glass

PLATE GLASS

-grounded and polished after drawn from furnace

-glass then pass through grinding unit

-polished smooth and parallel before cut

FLOAT GLASS

-has nearly optically true surfaced that is fire polished

-interchangable with plate glass for most application

-plate and float glass is stronger

-use in higher quality situations

-eg. showcase

SAFETY GLASS

TEMPERED GLASS

-heating regualr annealed glass almost until melting point and chilled rapidly

-thin skin of glass produced at both sides

-under high compression, places centre of glass in high tension

-tempered glass 3-5 times stronger

-breakable

-thin outer skin is pierced, glass shatters

-into small pebble like pieces

-safer than original glass

-must be cut before tempering

LAMINATED GLASS

-2 or more sheets of class stucked together with polyvinyl butral plastic between them

-binded under heat and pressure

-when broken, glass will adhere into plastic inter-layer without evacuating

-minimise cutting injury and hazards

-entrance door , interior partitions

WIRED GLASS

-metal wire mesh placed into centre of glass thickness during manufacturing

-glass pieces cling to wire when broken

-minimise flying of glass and injuries

-remain in one place even though cracked by excessive heat

SPECIAL GLASS FOR SPECIFIC PURPOSES

PATTERNED GLASS

-obscured optical properties

-insert patterns to glass

-allow differnt degrees of light transmission

-large range of patterns
-privacy use

-should be tempered for safety

INSULATED GLASS

-factory produced

-air tight unit consist of 2 layers of glass with a dehydrated air space in between

-protect window areas

-reduce heat loss in winter and heat gain in summer

-used in residental and commercial buildings

TINTED GLASS

-reduce soloar heat

-cut down glare

-to provide useful atmosphere

-grey and bronze tint

-windows, sliding glass doors, lirabries

REFLECTIVE COAT GLASS

-coated with thin layer of metallic-films

-reflect sunray

-reduce solar heat

-reduce aircon system cost

-grey, blue silver gold bronze

GLASS BLOCKS

-manufactured in two seperated halves

-heat sealed to form hollow unit

-with good thermal efficiency and sound insulation

-functional and directional

-functional: to diffuse/direct light that passes through them

-illuminates interior of building

-decorative: ability to control an overall design plan

-not intended to use as major control of daylight