The Doorman's Glossary

The ultimate glossary to help you navigate the world of doors and loading docks’ terminology.
We constantly add terms to help you better understand our products, so you could make more educated decision.
If you have any questions or want to consult a professional about your project, please contact us and we’ll be happy to help.

Air infiltration or air leakage is the passage of air in or out of a building. Leakage happens through cracks and gaps in the outside shell. Windows and doors leaking air is a significant culprit for air infiltration, and thus energy loss. Poor insulation around windows, doors, and vents contribute to air infiltration as well. The lower the air infiltration number, the more airtight the product is.

ASCE (American Society of Civil Engineers) provide a standardized formula to calculate and estimate wind load on structures. The value is represented as an ASCE wind load.

ASTM D 1929 is a class rating standard test method for determining ignition temperature of plastics. Values obtained by this test represent the lowest ambient air temperature that will cause ignition of a given material.

ASTM E 84 is a class rating standard test method for surface burning characteristics of building materials. The purpose of the method is to determine the relative burning behavior of a material by observing the flame spread and the smoke development. This test essentially helps to explore how the a material might contribute to flame spread in the event of a fire. The test indicates the Flame Spread index and Smoke Developed index of the tested material.

The lower portion of an overhead sectional door or rolling door designed to make contact at the bottom. Often it includes a rubber seal, and may also be outfitted with safety and security devices such as a safety edge or other types of sensors. Bottom bars can have varying shapes to meet surfaces that are uneven due to their construction. One example of such a shape is a wedge or sloping bottom bar used when the bottom of the opening is distinctly sloped. Some bottom bars also include weather seals and/or rodent proofing.

Counter balance or Counterbalancing mechanism comes in various forms. Its role is to assist in manually moving the door up an down with reasonable force by a human.

On a coiling or sliding door, the curtain is the part that retracts, enabling an opening to be “free to pass” or “secure” depending on the curtain’s position. A curtain can be made of a variety of materials including slats, panels, PVC, or a mix of fabrics. Common door curtains are typically coiling or folding.

Cylinder Locks provide a way to manually lock a roll-up door or a sectional overhead door with a cylinder key mechanism. These locks are usually located in the middle or the bottom of a door, and use one of numerous mechanisms to lock the door in place by anchoring the door to the guides (tracks) or the floor. Cylinder locks make it possible to manually lock the door from the outside with a key.

A drop stop device is a simple and effective device meant to save property from damage, personnel injury, or even death. it is used to keep the door from dropping in the event of failure in any of the components used to keep the door open.

Encapsulated insulation is insulation material that comes wrapped in polyethylene vapor retarder sleeve.

Composed of metals or plastics, end locks or endlocks, are mounted to the side edges of slat curtains to prevent the slats from shifting from side to side, which causes curtain wear and jamming. They are commonly bolted or riveted in place. They come in a variety of sizes and shapes depending on the curtain and needed functionality. Some types besides standard endlocks are windlocks, roller windlocks, and articulating roller windlocks.

Fenestrated slats or punched slats are slats that are fenestrated to a various degree. Many cutaway patterns can be used to achieve a punched slat design, such as hive-like small round holes pattern, which gives a solid net like door that allows air and some light in, or larger shapes cut-away to achieve a design that is closer to a rolling grille door.

The guides of a roller door limit it’s travel from side to side. They are commonly made of a composite of metal angles, but can be constructed in other ways as well.

Helical torsion spring is a type of spring commonly used for overhead doors to offset the weight of a curtain or a sectional door assembly. Unlike extension or compression springs, a torsion spring stores energy through the twisting of the ends of the spring. The shape of the spring is helical, as it is formed into a coil.

Lites are areas incorporated into a slat or section of a door in order to allow light to come in or to add the ability to see through the door. Lites transparency and materials can vary according to the specific needs and requirements.

Mullions are removable or static door tracks that are placed between doors to form additional columns. They can be used when multiple doors must be installed (for extra wide openings), or when a door spans a corner.

Outdoor/Indoor Transmission Class (OITC) rating is a way to estimate a wall or door’s ability to reduce typical transportation noise. It is determined in accordance with ASTM E 1332, a standard classification for rating outdoor-indoor sound reduction. Unlike the STC, which is based on a noise spectrum targeting speech sounds, OITC uses a source noise spectrum that considers frequencies down to 80 Hz (aircraft/rail/truck traffic) and is weighted more to lower frequencies. The OITC value is typically used to rate, evaluate, and select exterior glazing assemblies.

Perimeter seals are used to close the gap and create a tight fit between the door curtain or sections and the edges of the opening which the door covers. Adding perimeter seals lowers sound that travels through the gaps and helps with increased insulation. Perimeter seals come in various qualities and are made of different materials.

While traditional painting and powder coating are both “coating” processes, powder coating is more wear resistant and maintains color integrity longer due to its more intensive preparation before coating, its electrostatic application, and also its greater thickness applied. For more information about our powder coating services, see Powder Coating.

R-value is the inverse of U-value. It measures a wall or material’s ability to resist to heat flow. The higher the R-value, the more resistance the material has.

Many roll up curtains are made of slats, formed strips of sheet metal with eyes on their tops and bottoms where they slide together, They can be made of wood, and other materials as well. They come in a variety of sizes and profiles, and can be painted, powder coated, galvanized, or perforated. They can also be thermally insulated. American Door recommends end-locking the slats for extended curtain life, and decreased wear due to slat drift.

A slat’s profile has to do with its shape along the shortest edge. Most profiles are named for the part of the shape between the the top and bottom eyes such as “Flat,” “Single Crown,” and “Double Crown.” Their names can also include the height dimension of the profile such as two inch, three inch,or four inch. Some slats are doubled up (back to back) so that their profiles form a channel that is filled with thermal foam, such as a “Double Insulated Flat Slat”.

Slide Locks add a simple and effective way to manually lock a roll-up door or a sectional overhead door. These are levered locks that are mounted to the door and latch to the door guides (tracks), creating a physical lock that can’t be reached from the outside. Slide locks make it impossible to open the door with human force.

A sloping bottom bar is used when a door is installed on a slope. Since the slats of a curtain must fill the full width of a rolling door, only the bottom bar can be shaped to fill the diagonal area that is caused by the slope, in order for the door to perfectly fit the sloped area.

Smoke seals are a safety addition to fire rated doors. It is usually a brush type seal that keeps smoke from freely flowing through the door once shut.

The STC or Sound Transmission Class is a rating measurement of how well materials assembly reduces sound transmission. The STC provides a standardized way to compare products such as doors and windows. A higher number indicates more effective sound insulation.

A thermal break or thermal barrier is an element of low thermal conductivity placed in an assembly to reduce or prevent the flow of thermal energy between conductive materials. In some service doors that have high R-rating insulation, a thermal break material is used along the edges of each segment instead of rolled steel.

U-value is the inverse of R-value. It measures a wall or material’s ability to promote heat flow. The lower the U-value, the better the material as an insulator.

UL is a global safety certification company. It is one of several companies approved to perform safety testing by the U.S. federal agency, the Occupational Safety and Health Administration (OSHA).

Vision lites are areas in a rolling, sectional or high speed fabric doors which allow to see through the door and allow light to come in. Size, material and amount of vision lites can vary according to the specific needs and requirement.

A wicket door (AKA wicket, man door, door man door, or personnel wicket door) is a human size door or gate added to a larger entrance solution that is used by vehicles or machinery. This type of door can be used along with sectional doors, rolling doors, cantilever gates, sliding gates, large fenced gates etc.

Wind load is the force applied to a surface by the wind, which can be expressed as a force on the whole surface or as pressure (which is simply force per unit area). Wind load units for doors describe the amount of wind load force a door can handle.