Selecting the right commercial lock depends on the door construction, the level of security required, and the function the lock must perform. The two primary commercial lock types are cylindrical lever locks and mortise locks. Cylindrical lever locks are the most commonly used lock type in commercial buildings and install through two bored holes in the door. Mortise locks fit into a pocket cut in the door edge and provide the highest strength and durability for high-traffic, high-abuse applications. This guide covers the differences between these lock types, the grading system that defines their durability, and the lock functions available for different commercial door applications.
CDF Distributors ships complete door, frame, and hardware assemblies from its Nashville, Tennessee headquarters. You can configure and order your lock as part of a complete assembly using CDF’s ProBuilder tool at cdfdistributors.com. For assistance selecting the right lock for your project, call (855) 769-9895 or email sales@cdfdoors.com.
Commercial Lock Types
Commercial door locks fall into two primary categories: cylindrical lever locks and mortise locks. Each type differs in installation method, strength, cost, and the range of applications it serves. Panic bar exit devices are also used as primary door opening mechanisms in commercial buildings but are outside the scope of this guide.
Cylindrical Lever Locks
A cylindrical lever lock is a lockset installed by boring two circular holes in the door: a larger hole through the face of the door for the lock body and a smaller hole through the edge of the door for the latch bolt. This is referred to as a bored installation. Cylindrical lever locksets are the most commonly used commercial lock type. They are available in a wide range of functions, grades, styles, and finishes, making them suitable for the majority of commercial interior and exterior door applications.
Cylindrical lever locks are less expensive than mortise locks and faster to install. They are appropriate for standard commercial applications including offices, corridors, restrooms, storage rooms, and classrooms. When a project does not require the additional strength of a mortise lock, a cylindrical lever lock is typically the correct selection.
Mortise Locks
A mortise lock requires a rectangular pocket (mortise) cut into the edge of the door, into which the lock case is fitted. The lock case contains the latch bolt, deadbolt (if applicable), and the operating mechanism. Because the entire lock body is housed within the door, mortise locks provide greater structural strength than cylindrical locks.
Mortise locks are the strongest and most adaptable commercial lock type. They are designed to handle high-traffic, high-abuse applications such as hospital corridors, school entries, institutional facilities, and high-security commercial entrances. Mortise locks cost more than cylindrical locks and require more complex door preparation, but they offer superior durability and a wider range of integrated functions.
Lock Type Comparison
The following table compares the two primary commercial lock types across key selection criteria. Cylindrical lever locks are suitable for the majority of standard commercial applications, while mortise locks are the preferred choice for high-traffic and high-security installations where long-term durability is the priority.
Characteristic | Cylindrical Lever Lock | Mortise Lock |
Installation Method | Bored: two circular holes through the door face and edge | Mortised: rectangular pocket cut into the door edge |
Strength | Standard commercial strength | Highest strength; designed for high-abuse applications |
Durability | Suitable for standard traffic levels | Designed for high-traffic, high-abuse environments |
Cost | Lower cost | Higher cost |
Installation Complexity | Simpler; faster to install | More complex; requires mortise pocket preparation |
Typical Applications | Offices, corridors, restrooms, storage rooms, classrooms | Hospitals, schools, institutional facilities, high-security entrances |
Function Range | Wide range of standard functions | Wider range including integrated deadbolt functions |
Adaptability | Standard configurations | Most adaptable; supports the broadest range of lock functions |
Commercial Lock Grades
Commercial locks are graded according to ANSI/BHMA (American National Standards Institute / Builders Hardware Manufacturers Association) standards. The grade indicates the lock’s durability, security, and cycle life. Selecting the correct grade ensures the lock will perform reliably for the expected traffic level and lifespan of the installation.
Grade | Durability | Typical Applications |
Grade 1 | Highest durability; rated for high-traffic commercial use (800,000+ cycles) | Hospitals, schools, government buildings, institutional facilities, high-traffic entrances |
Grade 2 | Standard commercial durability (400,000+ cycles) | Offices, retail, light commercial, multi-family residential corridors |
Grade 3 | Light-duty; residential-grade durability (200,000+ cycles) | Residential, light commercial storage, low-traffic interior doors |
For most commercial projects, Grade 1 or Grade 2 locks are specified. Grade 3 locks are residential-grade and are generally not appropriate for commercial applications with regular traffic.
Lock Functions
Lock function defines how the lock operates from each side of the door. Selecting the correct function ensures the lock provides the intended level of access control, privacy, or security for the specific door application. The following table lists the standard commercial lock functions available in both cylindrical and mortise lock types.
Function | Description | Common Applications |
Passage | Latch bolt operated by lever from both sides; never locked | Corridors, closets, mechanical rooms where no locking is needed |
Privacy | Lever locks from inside with a thumbturn or push button; emergency override from outside with a small tool or coin turn | Restrooms, break rooms, private offices |
Storeroom | Outside lever is always locked and requires a key; inside lever is always free | Storage rooms, supply closets, utility rooms, server rooms |
Classroom | Outside lever is locked/unlocked with a key; inside lever is always free | Classrooms, conference rooms, offices requiring selective access |
Office / Entry | Outside lever is locked/unlocked with a key or thumbturn; inside lever is always free | Private offices, administrative areas |
Vestibule / Apartment | Deadlatch with key operation from outside; thumbturn or lever locks/unlocks from inside | Vestibule doors, apartment entries, tenant spaces |
Communicating | Both sides have a thumbturn or key that can independently lock/unlock the door | Connecting rooms, adjoining offices, conference suites |
Lock function availability varies by manufacturer and lock type. CDF’s ProBuilder tool displays compatible lock functions during assembly configuration, ensuring the selected function is available for the chosen lock type and grade.
How to Select the Right Commercial Lock
Lock selection is determined by three factors: the door application, the required security level, and the expected traffic volume. The following steps provide a structured approach to selecting the correct lock type, grade, and function.
- Identify the door application. Determine what the door is used for (corridor, restroom, storeroom, classroom, entry, etc.). This determines the lock function.
- Determine the traffic level. High-traffic doors (hospital corridors, school entries, main building entrances) require Grade 1 locks. Standard commercial doors (offices, conference rooms) are typically served by Grade 2 locks.
- Assess durability requirements. For high-abuse environments where doors are subject to heavy use, forced entry attempts, or institutional conditions, select a mortise lock. For standard commercial environments, a cylindrical lever lock is appropriate.
- Select the lock type. Use a cylindrical lever lock for standard commercial applications. Use a mortise lock for high-traffic, high-abuse, or high-security applications where maximum durability is required.
- Choose the lock function. Match the function to the door application. A storeroom function is always locked from the outside. A classroom function allows the teacher to lock/unlock from the hallway side. A passage function never locks. Select the function that matches the access control requirement for the specific door.
- Verify fire rating compatibility. If the door assembly is fire-rated, the lock must be listed for use in fire-rated assemblies. CDF offers fire-rated assemblies at 20-minute, 45-minute, 60-minute, and 90-minute ratings, as well as 3-hour ratings for masonry frame applications. All hardware in a fire-rated assembly must carry matching fire labels.
Lock Selection for Fire-Rated Assemblies
When a door assembly carries a fire rating, every component in the assembly—door, frame, hinges, lock, closer, and any glazing or louvers—must be listed and labeled for the specified fire rating. CDF Distributors fabricates fire-rated assemblies at five levels: 20-minute, 45-minute, 60-minute, 90-minute, and 3-hour. CDF rivets fire labels onto every fire-rated component before shipping.
Not all lock models are listed for fire-rated applications. During configuration in CDF’s ProBuilder tool, only locks that are compatible with the selected fire rating are presented as options. This ensures the completed assembly meets code requirements. Verify all fire rating requirements with your project’s design professional and the Authority Having Jurisdiction (AHJ).
Configure Your Assembly
CDF’s ProBuilder tool allows contractors and facility managers to configure complete door, frame, and hardware assemblies online. During configuration, ProBuilder displays compatible lock types, grades, functions, and finishes based on the door and frame selections. ProBuilder provides instant pricing and ensures all components are compatible.
For assistance selecting the right lock for your project, 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.
Frequently Asked Questions
What is the difference between a cylindrical lock and a mortise lock?
A cylindrical lever lock installs through two bored holes in the door and is the most commonly used commercial lock type. A mortise lock installs into a rectangular pocket cut into the door edge and provides greater strength and durability. Cylindrical locks are appropriate for standard commercial applications. Mortise locks are designed for high-traffic, high-abuse environments where maximum durability is required.
What lock grade do I need for a commercial door?
Most commercial projects specify Grade 1 or Grade 2 locks. Grade 1 locks are rated for the highest traffic and durability (800,000+ cycles) and are used in hospitals, schools, and institutional buildings. Grade 2 locks are standard commercial grade (400,000+ cycles) and are appropriate for offices, retail, and light commercial applications. Grade 3 locks are residential-grade and generally not appropriate for commercial use.
What is a storeroom function lock?
A storeroom function lock has an outside lever that is always locked and requires a key to operate. The inside lever is always free, allowing exit without a key. Storeroom locks are used on storage rooms, supply closets, utility rooms, and any door that should remain locked from the outside at all times.
What is a classroom function lock?
A classroom function lock has an outside lever that can be locked or unlocked with a key. The inside lever is always free, allowing exit at all times. This function allows a teacher or administrator to lock the door from the hallway side during a lockdown or after hours, while occupants can always exit freely from inside.
Can I use a cylindrical lock on a fire-rated door?
Yes, provided the specific lock model is listed for use in fire-rated assemblies. Not all cylindrical locks carry fire ratings. CDF’s ProBuilder tool displays only locks that are compatible with the selected fire rating during assembly configuration. CDF offers fire-rated assemblies at 20-minute, 45-minute, 60-minute, 90-minute, and 3-hour ratings.
What is the most durable type of commercial lock?
A Grade 1 mortise lock provides the highest combination of strength and durability available in a commercial lock. Mortise locks are designed to handle high-traffic, high-abuse applications. For standard commercial environments, a Grade 1 cylindrical lever lock also provides high durability at a lower cost.
How do I select the right lock function for my door?
Lock function is determined by how the door needs to operate from each side. Identify whether the door should always be unlocked (passage), lockable from inside only (privacy), always locked from outside (storeroom), or selectively locked by key (classroom or office). Match the function to the access control requirement for the specific door application.
About This Guide
This reference guide reflects CDF Distributors’ product specifications and the selection criteria used by commercial contractors, facility managers, and architects nationwide. CDF Distributors fabricates and ships complete door, frame, and hardware assemblies from its Nashville, Tennessee headquarters.
For questions about lock selection or to configure a complete door assembly, contact CDF at (855) 769-9895 or sales@cdfdoors.com. Configure your assembly online at cdfdistributors.com using ProBuilder.
