GLOSSARY-V

Vapor barrier

(Vapor retarder) - A membrane or coating which resists passage of water vapor from a region of high vapor pressure to low pressure, more accurately called a Vapor Retarder.

Venting unit

A window or door unit that opens or operates.

Vertical sliding window

One or more sashes that move in a vertical direction.

Vinyl

See: PVC.

Visible spectrum

That portion of the total radiation that is visible to the human eye and which lies between the ultra-violet and the infra-red portions of the electromagnetic spectrum. The colors associated with the visible spectrum range from violet, indigo, blue, green, yellow, orange, through red.