Chapter 17: Glass and Glazing

Question 1

Glass sheet formed by spinning an opened hollow globe of heated glass; uses an iron rod called a “punty”

Answer 1

Crown glass

Question 2

Glass sheet produced by blowing a large, elongated glass cylinder, cutting off its ends, slitting it lengthwise, and opening it into a flat rectangle. It is swung like a pendulum and reheated to form the rectangular sheet.

Answer 2

Cylinder glass

Question 3

Which was preferred: crown or cylinder glass? Why?

Answer 3

Crown glass was favored for its surface quality, while cylinder glass was more economical.

Question 4

What is the modern-day glass production method?

Answer 4

Float glass: glass sheet is manufactured by cooling a layer of molten glass on a bath of molten tin.

Question 5

What is the difference between glass and glazing?

Answer 5

Glazing is a part of a wall or window made of glass. It is the opening and the installation.

Question 6

The act of installing glass in a glazed opening; as an adjective, referring to materials used in installing glass; the “glazier” is the installer

Answer 6

Glazing

Question 7

Individual pieces of glass

Answer 7

Lights/lites

Question 8

Glass is the most-used cladding material for tall buildings due to:

Answer 8

• strength
• lightweight
• durability
• wide range of available optical and thermal properties

Question 9

Glass is made from:

Answer 9

60% sand
Soda ash
Lime
Alumina
Potassium oxide

Question 10

When ordinary glass is cooled slowly under controlled conditions to avoid locked-in thermal stresses that might cause it to behave unpredictably in use.

Answer 10

Annealed glass

Question 11

Glass that is strengthened by reheating annealed glass and then cooling both surfaces rapidly with bursts of air (quenching)
This includes heat-strengthened and tempered glass.

Answer 11

Heat-treated glass

Question 12

Heat-treated glass that is stronger than heat-strengthened glass and may be used as safety glazing. It does not shatter into large, sharp shards, but into small granules with square edges. It is annealed glass which is cut, reheated, and cooled rapidly.

Answer 12

Tempered glass

Question 13

Glass or plastic balling material that, when broken, does not create hazardous shards. It is permitted for use in buildings at risk of occupant impact. It is most commonly tempered or laminated glass.

Answer 13

Safety glazing

Question 14

Heat-treated glass that is not as strong as tempered glass, and may not be used as safety glazing.

Answer 14

Heat-strengthened glass

Question 15

A glazing material consisting of multiple outer layers of glass sandwiched to an inner layer of transparent plastic. The polyvinyl butrayal (PVB) interlayer is bonded to the two outer layers under heat and pressure.

Answer 15

Laminated glass

Question 16

A glazing sheet with multiple laminations of plastic and glass. Designed to stop bullets.

Answer 16

Security glass

Question 17

The ratio of solar radiation tar passes through a glazing unit to the amount of lighting striking the unit, weighted to account for the relative fading damage potential of various wavelengths. The lower the Tdw, the better the protection against fading to interior fabrics and materials.

Answer 17

Damage Weighted Transmittance (Tdw)

Question 18

Glass strengthened by immersion in a molten salt bath, causing an ion exchange at the surface of the glass that creates a prestress in a manner similar to heat-treated glass

Answer 18

Chemically-strengthened glass

Question 19

What is the difference between fire-protection and fire-resistance glazing?

Answer 19

Fire-protection: used in fire doors, windows and other protected openings.

Fire-resistance: capable of substituting in full for solid, fire-resistance-rated wall assemblies. Unlike fire-protection rated glazing, resistance is not limited to use in doors, windows, or other openings. This glazing will not catch fire as quickly.

Question 20

Ground-up colored glass that is heat-fused to lines of glass to form functional or decorative patterns. It imprints the glass.

Answer 20

Frit

Question 21

Opaque glass manufactured especially or use in spandrel panels. Usually tempered or heat-strengthened with insulation behind it.

Answer 21

Spandrel glass

Question 22

Glass that is colored with pigments, dyes, or other admixtures (adding small amounts of chemical elements to the molten glass mixture)

Answer 22

Tinted glass

Question 23

Glass onto which a thin layer of metal or metal oxide has been deplored to reflect light and/or heat. Turns away significant portion of solar radiation.

Answer 23

Reflective coated glass/solar control glass

Question 24

A glazing unit made up of two or more sheets of glass with an airspace in between.

Answer 24

Insulating glass units (IGUs)