Flat glass is the main type of architectural glass. It offers a clear, transparent surface, sound and thermal insulation, wear and weather resistance, and material stability. Its main raw materials include quartz sand, sandstone or quartzite, limestone, feldspar, dolomite and soda ash. Production involves crushing, screening, batching, high-temperature melting, forming, annealing, cooling and further processing. Glass was initially used in buildings primarily for daylighting. As glass types and performance have developed, and demand for environmental protection and energy efficiency has grown, buildings have placed higher requirements on glass, particularly in the following areas:

（1）Daylighting

Daylighting is a basic function of glass, but current requirements go beyond simply admitting sunlight. Designers also consider the angle of daylight, visual effects, savings in artificial lighting, indoor shading, light transmittance, and image distortion.

（2）Safe

Historically, inadequate attention to glazing safety allowed breakage from natural forces and human impact to cause injuries, deaths, and property damage. China has since introduced safety requirements that call for design assessment before installation. The assessment considers whether the glazing remains safe under wind pressure, thermal stress, hail, falling objects, earthquakes, and human impact.

（3）Energy saving

Building energy efficiency is an important part of the overall energy-saving agenda. Choosing appropriate energy-efficient glass is one way to reduce a building’s energy use.

(4) Fire protection

Glass with fire-protection properties must be used along a building’s fire-escape routes. It should allow people to see how far the fire has spread while resisting the passage of flames for a period of time, enabling evacuation.

（5）Security

Bullet-resistant glass, security glass, and alarm glass help protect assets and improve the security of entrances, exits, and partitions in important buildings. Their wider use in residential construction can reduce the need for unattractive iron window grilles and doors, preserving the building’s appearance while providing security.