What is the difference between a cylindrical lockset and a mortise lock?

A cylindrical lockset installs through a round bored hole (161 prep, 2-1/8” diameter) in the door face. A mortise lock installs into a rectangular pocket (86 edge prep, 8” cutout) cut into the edge of the door. Mortise locks are heavier duty and offer more function options, but they require a thicker door stile to accommodate the lock body. Both types are used in commercial applications.

What do the fire rating levels mean for commercial doors?

Fire ratings indicate how long an assembly can resist fire in a standard test. The five standard levels are 20-minute, 45-minute, 60-minute, 90-minute, and 3-hour (180-minute). The required rating depends on the wall’s fire resistance rating and the opening’s location in the building. All components in the assembly, including door, frame, hardware, and glazing, must carry matching or compatible fire labels.

What is the difference between a drywall wrap frame and a welded frame?

A drywall wrap frame ships in three pieces (head and two jambs) and installs after the wall is finished by wrapping around the drywall edges. A welded frame is a one-piece unit with the head and jambs factory-welded together, typically set during wall construction in masonry or concrete applications. Drywall wrap frames are standard for interior commercial applications in metal stud walls.

What does "hand" or "handing" mean on a door schedule?

Handing describes the swing direction of a door. Stand on the outside (key side) of the door and note which side the hinges are on. Hinges on the right means Right Hand (RH); hinges on the left means Left Hand (LH). If the door swings toward you, add "Reverse" (RHR or LHR). Correct handing is essential when ordering locksets, exit devices, and closers because many hardware items are hand-specific.

What gauge steel should I specify for commercial door frames?

Standard commercial interior frames are typically 16 gauge (0.0598”) or 14 gauge (0.0747”). For high-traffic areas, high-security applications, or frames receiving heavy hardware, 14 gauge or 12 gauge (0.1046”) is appropriate. The project specifications or architect typically dictates the required gauge.

What is a 161 prep and an 86 edge prep?

A 161 prep is a 2-1/8” diameter hole bored through the face of a door to accept a cylindrical (bored) lockset. An 86 edge prep is an 8” rectangular cutout in the edge of a door to accept a mortise lock body. The prep type is determined by the lockset type specified in the hardware schedule. Doors must be ordered with the correct prep to match the specified hardware.

Do all components in a fire-rated opening need to be fire-rated?

Yes. NFPA 80 requires that every component in a fire-rated opening carry a matching or compatible fire label. This includes the door, frame, hinges, lockset, closer, glazing, louvers, smoke seals, and any other component installed in the assembly. Missing or mismatched labels can cause the assembly to fail inspection by the Authority Having Jurisdiction (AHJ). Fire labels are available at all five standard rating levels: 20-minute, 45-minute, 60-minute, 90-minute, and 3-hour (180-minute).

What finish should I specify for commercial door hardware?

The most commonly specified commercial hardware finish is US26D (626), satin chromium, which provides a durable matte silver appearance. For environments with moisture or chemical exposure, US32D (630) satin stainless steel is preferred. The finish should be consistent across all hardware on each opening. CDF’s ProBuilder displays available finishes for each hardware selection during the configuration process.

Frequently Asked Questions

CDF’s ProBuilder tool allows contractors and facility managers to configure complete door, frame, and hardware assemblies online. ProBuilder uses the terminology defined in this guide throughout the configuration process, displaying compatible options for each selection. During configuration, ProBuilder automatically applies correct preps, gauges, and fire rating requirements based on your selections.

For assistance with terminology on your project’s door schedule or hardware specifications, call (855) 769-9895 or email sales@cdfdoors.com. CDF’s sales team is available Monday through Friday, 7:30 AM to 4:30 PM CT.

Configure Your Door Assembly

The following terms appear in specifications, submittals, and hardware schedules but do not fit neatly into a single category above. They cover standards organizations, measurement conventions, and operational concepts that contractors encounter across commercial door projects.

Additional Industry Terms

Frame installation and wall construction terms describe how frames are anchored, how walls are built, and how the frame integrates with the surrounding structure. These terms appear frequently in architectural specifications and on construction drawings.

Frame and Wall Construction Terms

Commercial door hardware and hollow metal assemblies are specified with standardized finish codes. These codes identify the color, texture, and coating type for doors, frames, and hardware. Matching finish designations across all components ensures a consistent appearance. The following table lists the most commonly specified finishes in commercial construction.

Finish Designations

Fire-rated door assemblies are required by building codes at specific locations to prevent the spread of fire and smoke. A fire-rated assembly includes the door, frame, hardware, glazing, and any other components, all of which must carry matching fire labels. Fire ratings are assigned in five standard levels: 20-minute, 45-minute, 60-minute, 90-minute, and 3-hour (180-minute). The following terms define key fire rating concepts.

Fire Rating Terms

Hinges are the primary door-hanging device in commercial construction. The type of hinge specified depends on the door weight, frequency of use, fire rating requirements, and security needs. All hinges for fire-rated openings must be steel, bearing-type hinges. The following table covers the most common commercial hinge types.

Hinge Types

Keying systems in commercial buildings control which keys open which doors. A properly planned keying system balances security with convenience, allowing building managers to maintain access control across departments, floors, or entire facilities. The following terms describe the most common keying concepts.

Keying Terms

Lock function describes how a lockset operates, specifically which side locks, which side is always free, and how the lock is controlled. Lock functions are standardized across the industry, and each function has a specific use case. Specifying the wrong lock function can create code violations or security gaps. The table below lists the most common commercial lock functions.

Lock Functions

Commercial door hardware includes all of the devices that control how a door operates, locks, and closes. Hardware is specified in a hardware schedule or hardware set, which lists every device for each opening in a project. The following terms cover the major categories of commercial door hardware.

Hardware Types

Commercial steel frames consist of multiple components that work together to support the door, receive hardware, and integrate with the surrounding wall construction. The following terms describe the parts and features of hollow metal door frames.

Frame Components

Commercial doors are manufactured with specific components that differ from residential construction. Understanding these components is essential when reading hardware schedules, ordering replacements, or specifying new assemblies. The terms below cover hollow metal and wood door construction.

Door Components

Steel gauge numbers and door prep designations appear on virtually every commercial door schedule. Gauge numbers indicate the thickness of the steel used in doors and frames, while prep numbers specify the cutouts required for specific lock and hardware types. The following table defines the most common gauge and prep terms.

Steel Gauge and Door Prep Terms

This glossary is compiled from CDF Distributors’ technical documentation, industry standards published by the Steel Door Institute (SDI), the Door and Hardware Institute (DHI), and NFPA 80 fire door assembly requirements. CDF’s engineering and sales teams use these terms daily when fabricating hollow metal assemblies, consulting on hardware schedules, and supporting contractors in the field. The definitions reflect current commercial construction practice in the United States.

About This Guide

Commercial door and hardware terminology covers the specialized vocabulary used across hollow metal doors, steel frames, locksets, hinges, closers, and fire-rated assemblies. This reference guide defines over 100 terms organized by category, giving contractors, facility managers, and specifiers a single resource for understanding the language used in door schedules, hardware specifications, and architectural drawings. Each category below groups related terms so you can quickly find the definition you need during takeoffs, submittals, or field installation.

CDF Distributors provides complete commercial door, frame, and hardware assemblies shipped from its Nashville, Tennessee headquarters. You can configure and order online using CDF’s ProBuilder tool at cdfdistributors.com. For assistance selecting the correct components for your project, call (855) 769-9895 or email sales@cdfdoors.com.