GLOSSARY-D

Day Light Opening (DLO)

The visible area; glass to glass dimension of a window or door (what you can see).

Deadbolt

Locking mechanism for an entrance door or other door. Deadbolts can be a single cylinder or double cylinder. With a single cylinder deadbolt, a key is used on the outside and is turned by hand on the inside. With a double cylinder deadbolt, a key is used on both sides. Double cylinders are only recommended where no one needs to go through a door in case of an emergency.

Desiccant

A drying agent, such as silica gel, used by some manufacturers between the panes of insulating glass to prevent fogging between the panes.

Design Pressure (DP)

A numerical value that defines the structural wind loading requirements (in pounds per square foot) for a building and its components. Usually specified as one-and-a-half times greater than necessary based on expected building, wind and weather conditions.

Dew point temperature

The temperature of the air, at which the water vapors in the air, starts to condense in the form of liquid or as frost.

DGK (Double-applied Grill Kit)

lay in grill kit; made of the raised or flat muntin on the exterior and raised or flat bar on the inside.

Double glazing

Use of two panes of glass in a window or a door to increase energy efficiency and provide other performance benefits.

Double-hung window

A window with two vertically moving sashes, each closing a different part of the window.

Double window

Two windows separated by a mullion, forming a unit. Also called: a coupled window.

Drip cap

A horizontal molding to divert water from the top casing so that the water drips beyond the outside of the frame.

Dry glazing

A form of glazing in which the glass is secured in the frame with a dry gasket, wood stops, or metal stops, instead of by a glazing compound.

Dynamic range

The range of variation between its darkest state and its clearest state that a switchable glazing is capable of. So, for example, a dynamic range of 3.5-64% means that on the low (dark) end, it blocks all but 3.5 percent of incoming visible light and almost all the heat, and on the high (clear) end, it blocks only 36 percent incoming light, and allows in more solar heat.