Glossary of Roll Up Door Industry Terms

The following door glossary will provide you with a more in-depth understanding of common door hardware terms. This comprehensive rolling door components, parts of overhead doors and coiling door parts glossary contains everything you need to know about doors, door components, and related hardware used in door installations.

Access Panel
An opening in a ceiling for access to tension adjusting wheel and to drive mechanism (motor, crank, chain hoist). Furnished by the ceiling or General Contractor.

Adjusting Wheel
See Tension Wheel for rolling door components.

All Weather Doors
A rolling service door having all the weather-stripping features, consisting of guide weather-stripping, hood baffle and bottom astragal.

Astragal
Neoprene or vinyl weather-stripping added to the bottom bar to seal opening along the floor or to protect a finished surface.

Automatic Closing
Mechanical, self-closing device of a fire door upon melting of a fusible link, or activated by smoke detector or alarm system.

Backroom
Amount of clear unobstructed space extending back from the face of the wall.

Barrel Assembly
A steel tube or pipe that spans between the door brackets and contains the springs required to provide counterbalance and lifting capability. The curtain coils up around the barrel.

Barrel Ring
Stamping or casting, attached to counterbalance pipe or barrel, which is used to increase the curtain wrap diameter and which is attached to the curtain top slat.

Bar Stop
See Wind Bar.

Base Plate
Optional steel plate mounted under the tube support to help transmit weight of tube and product on floor.

Bellmouth
Flared upper portion of guides to ease entry of curtain into the guides.

Between Jamb Mounted
Type of mounted where the guides are positioned between the mounting surfaces and not on the surface (interior or exterior) of the wall. Guides are generally “packed out” mounted to the inside of jamb and hood below lintel. Clear opening size will be reduced and may require “fascia” to close off back of hood.

Bottom Bar
A reinforcing member at the bottom of a curtain; generally either two angles back-to-back forming an inverted “tee” or an extruded aluminum member. Serves to add lateral strength to door, to add weight to help curtain close, to act as an obstacle to stop door when fully open, as a stop plate, and to hold weather-stripping.

Bracket Plates
End supporting plates for the barrel counterbalancing assembly and to house coiled curtain rolling door components. One plate is the drive (chain hoist, crank or motor side) plate, the other is the tension (spring adjusting side) plate. Each bracket plate is generally supported by the wall angle of the guide assembly.

Brush Seals
Term used to refer generically to the use of brush filament material either in use as a weather-seal or when used as smoke seals for smoke and fire doors.

Brush Weather-stripping
Weather-stripping for use on all configurations of doors to close the gaps at jambs and header. Brush material can be UL listed for “fire door” use.

Cable Sensor Edge
An edge that uses two cables inside a standard neoprene loop astragal. Upon connection with motor operator, a sensing field is established between the two cables. Any disturbance to this field causes the motor and door to stop and reverse (or stop).

Chain Hoist
A mechanical device to assist in raising and lowering the door by use of hand chain and gear or sprocket reduction.

Charge Pin
A metal pin used to lock tension wheel after proper spring tension is applied.

Charge Wheel
See Tension Wheel coiling door parts

Counter Shutter
A door used to close an opening which includes a counter-type sill.

Counterbalance
A system of springs or weights to provide the amount of force needed to raise the door and maintain it in the open position.

Curtain
The parts of overhead doors that actually rolls up and down, or slides side to side. It may be manufactured of slats and/or rods and links, endlocks and windlocks.

Cycle
An action on the door from the fully closed position, to the fully open position, and returned to the fully closed position.

Cylinder Lock
Key-operated locking device located on the bottom bar to lock parts of overhead doors.

Door/Grille Combo
Combined assembly of a rolling service door and a rolling grille door sharing guides and common bracket plates. Allows full security when required and ventilation with door open and grille closed.

Double Throw Lock
Center locking device that throws a locking bar into both guides, mounted on bottom bar.

Drive Gear
Large gear for chain- or crank-operated units. It is directly fastened to the door shaft on the drive side bracket plate.

Drive Plug Assembly
See Plug End rolling door parts

Drive Shaft
The shaft in the barrel that is securely attached to the barrel, through welding or pinning. When this shaft rotates the barrel should also rotate.

Dropout
Weighted mechanical device for disengaging gearing or motor operator for rolling fire doors. Also used to activate closing spring and to release governor in case of fire.

Drop Test
Test performed on a fire door to ensure proper operation during emergency. Testing is required to be performed annually (see NFPA 80).

“E” Guides
Common expression for the shape that guides form when they are mounted to steel jamb supports or frames.

Electric Sensor Edge
See Sensing Edge coiling door parts.

Electromechanical Release

A device, which holds the auto, close device until it is released by a signal from an alarm or detection system. If power fails the device also releases. There are a variety of types and manufacturers of rolling door components. Most have a time delay before release to prevent nuisance releases.

Emergency Electric Operation
Any rolling door with a motor and an Uninterruptible Power Supply (UPS) capable of opening and closing the door several times while facility line power is off.

Emergency Release Device
Permits emergency egress (exit). Normally furnished on grilles in Malls/Shopping Centers where building codes dictate. Parts of overhead doors which allow manual operation of the door without electrical power to open.

Endlocks
Steel stamping or malleable iron castings which are riveted to curtain slats ends every other slat to prevent slats from shifting laterally, and to provide curtain wearing surface in guides. “Alternate endlocks” are at both ends of every other slat, commonly for service and parts of overhead doors and rolling door parts. “Continuous endlocks” are both ends of every slat.

Endplates
See Bracket Plates coiling door parts.

Exterior Mounted
Condition where door is mounted on exterior surface exposed to weather and wind load. Usually requires “exterior hood” and “gear covers”.

Face of Wall
Door mounting condition where guides mount directly to wall, and side clearance is allowed for tension wheel and drive mechanism.

Fascia
Metal closure for back of door housing. Coiling door parts required when there is only a partial or no header in place and back of door coil is exposed. Rolling door parts required when the wall above header is not full thickness of jamb (prefab building).

Fenestrated Slats
A curtain with holes or slots in slats to allow air filtration

Fire Door
A door that has a fire protection rating and will close the floor automatically in case of fire.

Fire Shutter Door
A door that has a fire protection rating and will close to the floor or counter top automatically in case of fire.

Flame Baffle
Parts of overhead doors with hinged metal shield released by a fusible link inside a fire door hood.

Fuse Link Housing
Box in which fusible links are sometimes furnished when rolling fire doors are mounted above ceiling to provide a finished exposure are in ceiling for link.

Fusible Link
Two metallic pieces that are joined together by low temperature alloy. When the ambient temperature exceeds that of the alloy the connection melts and the pieces separate. These are used to release holding chains or cables that maintain a mechanical fire door release system. The most common temperature for a fire door is 165 degree F.

Gear Cover
Metal cover protecting the drive brackets to control rate of descent of rolling fire door when released in the event of fire.

Governor
Device on rolling fire door drive mechanism from weather and debris.

Grille Door
An upward acting rolling gate-offering security without loss of visibility or ventalation. Widely used in shopping malls and parking areas.

Guide Assembly
Consists of two or more angles or a roll-formed channel to create a groove in which the rolling curtain moves up and down.

Guide Standout
The distance that face-mounted guide assembly extends from wall face.

Guide Weatherseal
(1 seal): A strip of weather-stripping material that is attached to the exterior guide angle and designed to compress against the exterior surface of the curtain slats. The material may be vinyl, neoprene rubber, or brush filaments.

Guide Weatherseal (2 seal)
The weather-stripping material is applied on both the exterior and interior guide angles and is designed to compress against both the interior and exterior curtain surfaces.

Gussets
See Bracket Plates rolling door parts.

Hand of Operations
The side on which the door operation mechanism is placed, as viewed from the coil side of the door. It is either an RH or LH operation,

Header Seal
Weather-stripping mounted to opening header to seal the opening between header and curtain, sometimes used where hood baffles is ineffective.

Headplates
See Bracket Plates coiling door parts.

Headroom
Amount of clear unobstructed space above the door lintel or header.

Helical
It means a spiral, and is a term referring to the type of torsion spring used in the spring counterbalance.

Hogh Cycle Design
Door Components and operator designed for a fixed number of cycles for a specific period of time.

Hood
Metal cover that conceals the doors/grille coil and is attached and supported by headplates and intermediate hood supports (if required in parts of overhead doors).

Hood Baffle
A flap of material secured to the interior of the door hood, resting on the curtain roll and designed to retard air infiltration over and through the hood.

Housing
See Hood rolling door parts.

Inertia Brake
A unit that is attached to the door shaft and headplate or wall, which will stop the door from free falling should there be a failure in the motor operator brake, roller chain drive or torsion spring assembly. When the shaft is moving at a certain RPM the unit will lock up the shaft, preventing it from moving until door can be repaired.

Initial Charge
See initial Turns coiling door parts.

Initial Turns
Amount of turns of the tensions shaft to apply spring tension from zero with the door in the fully open position. These turns provide the minimum momentum or force to hold door in the open position.

Inset
See Setback.

Inside Adjusting Wheel
See Inside Tension Wheel.

Inside Tension Wheel
Spring adjusting wheel located inside bracket plate so that no additional sideroom is required beyond the guide.

Interlock, External
An electrical switch to prevent motor operation if locking device is not first disengaged. Not to be confused with interlock of emergency hand chain operator.

Intermediate Hood Support
A rigid member, which is contoured to the shape of the hood and mounted to the wall, between the headplates. The hood is then attached to the support to give the hood rigidity.

Jamb
A vertical member at either side of a door or window frame housing the parts of overhead doors.

Jamb angle
An angle of the guide assembly in which it attaches to the inside of jamb and supports the load of the door assembly.

Jamb Load
Force exerted on jamb by guide assembly when curtain is subjected to wind load.

Label Size
the largest size of a fire door or fire shutter assembly fire proven by test to meet a specific fire rating.

Lift Handle
A handle supplied on manual push-up doors, to assist in raising and lowering the door.

Magnetic Release
Device connected to a smoke detector or alarm system, that on either an interruption of electrical power or applied signal will release the automatic closing device of a fire door or fire shutter.

Manual Override
Means of operating a motorized shutter by manual operation in case of power loss.

Master Keying
Arrangement whereby cylinder can be opened or locked by means of one “master” key.

Motor Cover
Metal cover to protect the motor from exterior weather, debris, or to meet OSHA safety requirements of rolling door parts.

Mullion, Motorized
A combined guide assembly joining two adjacent rolling doors where center guide is hinged and motorized to lift up and out of the way, to expose a full opening width when both doors are open.

NFPA 72, National Fire Alarm Code
Code deals with the application, installation performance, maintenance fire alarm systems and their components.

NFPA 80, Standard for Fire Door and Fire Windows
Regulates the installation and maintenance of assemblies and device used to protect openings in walls, floors, and ceilings against the spread of fire smoke within, into, or out of buildings.

Offset
Dimension between face of header or jamb and centerline curtain. Required to reduce drag of curtain on bellmouth of guides when curtain is in a lowered position.

Oversized Label
A fire door or fire shutter assembly that has not been fire tested, and receives a label or a Certification of Inspection which does not indicate that the door is capable of furnishing “ Standard Fire Protection”, but only that the door conforms to the construction requirements of coiling door parts.

Packout
Guide build-out to cleat an obstruction or provide clearance for drive or tension mechanism when door is between jamb mounted.

Panic Release Device
See Emergency Release Device.

Pass Door
Hollow –metal pedestrian door integrated into the rolling door, the frame of which is hinged at the jamb so door frame swings out of the opening.

Perforated Slats
See Fenestrated Slats as parts of overhead doors

Pipe Shaft
See Barrel Assembly

Plug End
Drive end of barrel assembly driven by gear or sprocket for which the curtain is raised and lowered. Consists of a coiling door parts assembly of short solid shaft and one or more round plates welded to the shaft and pipe whith in the pipe.

Pre-Turns
See Initial Turns

Safety Stop Bearing
See Inertia Brake rolling door parts.

Security Chain Box
Metal enclosure that encloses hand chain in a steel pad-lockable assembly attached to door guide.

Sensing Edge
A device mounted on the bottom bar of an electrically- operated door to stop or stop-and-reverse the closing door upon contact with an obstruction in the door opening.

Sensing Edge, Pneumatic
An air hose installed inside the bottom bar astragal and connected to a diaphragm switch, to signal the motor operator to stop or stop-and reverse the door.

Sensing Edge, Electric
An electrical bottom bar astragal enclosed with two parallel foils. When closing door bottom bar touches an obstruction, the foil close an electric circuit to cause the operator to stop or stop-and-reverse the door.

Sensing Edge, Infrared Type
Bottom bar astragal enclosing a tube with an infrared transmitter at one end and a detector at the other end. When IR source is obstructed the motor operator will stop or stop-reverse the door.

Service Counter Fire Door
A small version of a fire door where the combined door, still, and frame (optional) assembly has a fire protection rating and will automatically close to a counter top in case of fire.

Setback
A standard space where the guide is recessed from edge of the jamb at both sides of opening on a face of wall-mounted door.

Sideroom
Required unobstructed space where the guide is recessed from edge of the jamb at both sides of opening on a face of wall-mounted door.

Slat
Cold roll-formed or extruded member of which curtain is formed. Slats are formed so as to interlock and form a water-shedding surface.

Slide Bolt
Locking device on the bottom bar which slides into guide or guide shoe and is equipped for padlocking. Mounted either inside, outside or both sides of the door.

Slide Grille
A side-sliding grille product the requires little headroom and no floor track. The grill is able to follow a curved lease line and stacks into a side pocket in the wall.

Sloped Bottom Bar
Tapered bottom bar rolling door parts to match sloped sill of opening. Accomplished by inserting a tapered plate between bottom bar angles. This tapered plate will hang into opening on low side unless door height is increased and coil raised to have sloped bar cleared opening when door is open.

Smoke Detector
A device that senses visible or invisible particles of combustion and/or heat.

Smoke Gasketing
Brush seal used on the fire doors or fire shutters to reduce the passage of smoke and gases.

Spot-Type Detector
A device with a detecting element concentrated at a particular location. Typical examples are bimetallic detectors, fusible alloy detectors, certain pneumatic rate of rise detectors, certain smoke detectors, and thermoelectric detectors.

Spring Cycle Life
spring counterbalance is designed for a fixed number of cycles.

Spring Counterbalance
See Barrel Assembly.

Stand-Out
The distance that guides assembly extends out from the wall on face-of-wall mounted doors.

Starter, Fire Door
A mechanical device to start the closing of door in the event of a fire and to do it independently of the hand chain, crank or motor operator normally used to close door.

Starter Slats
Partial slats used to connect curtain to barrel rings.

Stops
Bars mounted at top of guides to prevent bottom bar from traveling out of the guides when the curtain is fully raised.

Stop Lock Bearing
See Inertia Brake.

Tapered Bottom Bar
See Sloped Bottom Bar.

Tension Wheel
Casting, either pinned or keyed to the spring inner shaft, with which the counterbalancing springs are initially tensioned or adjusted, and is used in conjunction with a locking pawl or pin to lock adjustment.

Thru-Wall Operation
A door driven by means of hand chain, crank or motor operator located on the opposite side of wall.

Thru-Wall Fusible Link
Extending a fuse linkage to the opposite side of an opening, with respect to the side the door is mounted on. Required per NFPA 80 for all non-exteriors mounted doors.

Thumb Turn Mortise Cylinder
Locking device, much like a cylinder lock but does not require a key to lock or unlock.

Torsion Spring
A helical wound spring, commonly mounted directly into the pipe and electrically drives the barrel assembly.

Viscous Speed Governor
Device to control the drop rate on fire doors.

Vision Lite
A series of single cutouts in door, glazed with clear plastic.

Wall Angle
An angle of the guide assembly, which attaches to the face of wall and supports the load of the door assembly.

Wicket Door
see Pass Door.

Wind Bar
channel or bar welded inside guide groove, which engage windlocks under wind load.

Windlocks
Malleable iron castings riveted at predetermined intervals to slat ends to prevent curtain from leaving guides under wind load, and which are used in conjunction with channels or wind bars in guides which windload engage under wind load.

Working Turns
The additional winding of the springs as the barrel rotates and the curtain closes.

Thank you for viewing Alpine’s glossary of terms for rolling door components, parts of overhead doors, coiling door parts.