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New Zealand Home & Building, October-November 1985

The Standard: An Overview

page 82

The Standard: An Overview

Is a lounge suite worth more than a life? One would assume not but we know of a case recently where a new home owner paid extra to have solar control glass fitted to prevent a lounge suite fading, while refusing safety glass as being too expensive for the benefit.

Annealed glass: sharp, jagged, shards can kill.

Annealed glass: sharp, jagged, shards can kill.

Toughened glass: up to five times as strong as annealed glass of the same thickness, when broken it shatters into harmless granules.

Toughened glass: up to five times as strong as annealed glass of the same thickness, when broken it shatters into harmless granules.

Laminated glass: a tough polyvinyl interlayer bonds the glass even when broken, preventing falling glass and resisting penetration by bodies or objects.

Laminated glass: a tough polyvinyl interlayer bonds the glass even when broken, preventing falling glass and resisting penetration by bodies or objects.

The new Standard for glazing to be released this month goes some way toward increasing the use of safety glass in hazardous situations, but, according to some industry leaders, it does not go far enough.

The Standard is the result of five years of close consultation with all sectors of the glass and glazing industries. The experience of the Australian and United Kingdom Standards has also been used.

Following the Australian Standard AS 2208, safety materials have been divided into Grades A (the highest) and B. The grade is determined by penetration resistance in a swinging ball test.

Grade A includes toughened and laminated. Under Grade B — wired glass is included.

The main emphasis of the human impact section of the new Standard is a requirement to increase the thickness of annealed glass in all but the most limited of applications.

A presumption is made in favour of safety glazing unless annealed glass can be safely used. This entails restrictions on the extent and areas in which annealed is permitted.

The theory is that glass breakages and the likelihood of cutting and piercing injuries will be minimised by the limited size of the glass, or by the fracture characteristics of the safety material.

Certain areas are considered hazardous. These include patio doors made of glass; doors with glass panels; unframed glass doors; shower doors, screens and bath enclosures; glass used at low levels — including floor to ceiling windows; and glass balustrades or free standing use of glass.

Patio doors have caused most concern in the past. The Standard will effectively require full pane glass patio doors to be glazed in safety material. If annealed is to be used, under normal circumstance it would be a minimum of 5mm thick and the door must contain a sight or crash rail.

Shower doors, screens and bath enclosures are also hazardous areas. The Standard states that they always be glazed with safety glazing, preferably toughened glass to withstand thermal shock. If their edges are exposed then toughened must always be used.

Balustrades may use either Grade A or Grade B safety glass, except when partly or completely unframed. In such cases, only Grade A safety material may be used.

The Standard specifies that special purpose buildings, including gymnasia, should always be glazed in Grade A materials.