Glassary - V

Vandal resistance:
the ability to resist damage, as opposed to the ability to resist penetration. We do not have an "unbreakable glass". See Product Data Sheet Pilkington Security Glass and Technical Bulletin Glass and Security.

Vent hole:
usually a round hole cut into an insulating glass unit for a fan or ventilator.

Venetian striped mirror:
This product is now known as Pilkington Mirropane™ Venetian Stripe (see Product Data Sheet for further details). It consists of a mirror where the backing paint has been sand blasted in parallel lines. This creates alternate clear stripes and silvered stripes. These can create a one-way vision effect to allow discrete observation.

Vertical glazing:
glazing which is either true vertical or within 15 degrees of true vertical.

Visible spectrum:
that part of the electromagnetic spectrum, which is visible to the human eye, i.e. at wavelengths between 380 and 780nm.

Vision area:
depending on the context, either:

• an oval with axis equal to the height and width of the pane, or
• the parts of a building façade or curtain wall which are intended for the passage of light.

Vision panel:
depending on context, either:

• a term used to distinguish a part of curtain walling as being distinct from the spandrel panel or
• a small pane of glass in a door to alow people to look through without necessarily opening the door.

Visual distortion:
the warping of images when seen through the glass, due to the surfaces of the glass being not exactly flat and parallel. The term also sometimes applied to reflected images.

Visual quality:
an alternative term for optical quality.