April 15, 2026
Writing mortise lock specifications takes care and attention. Small missed details often lead to RFIs, schedule delays, or doors that need rework. Many of these issues start with unclear language or missing prep details.
Mortise locks are not forgiving. They require exact door prep, correct dimensions, and clear function calls. When specs lack this detail, installers face problems in the field. That can slow inspections and raise costs.
Architects should specify mortise locks with the same care used for doors and frames. That includes lock type, function, prep, and finish. It also means planning early for access control when required.
Clear mortise lock specifications help keep projects on track. They also help owners get doors that work as intended on day one.
This article focuses on two commercial mortise lock options from PDQ. The MR Series covers mechanical needs where a mortise lock with key is the right fit. The MR199 Series supports openings that require electrified control.
What Defines a Mortise Lock
A mortise lock installs inside a pocket cut into the door edge. The lock body sits within the door, not on the surface. This design supports heavy use and secure latching.
Mortise locks are trusted for strength, longevity, and security. They also support anti-panic, one-motion egress.
Mortise locks are also highly repairable. Institutions routinely stock cams, springs, and parts to keep locks performing like new. With proper maintenance, a quality mortise lock can last 60 years or more.
Specifiers can also choose from a wide range of lever designs, trim configurations, functions, finishes, and keying options.
Common traits include:
- Solid metal chassis inside the door
- Separate trim, latch, and bolt components
- Support for many mechanical and electrified functions
- An optional built-in deadbolt for enhanced security
- Anti-panic one-motion egress capability
- Latchbolt position monitoring capability
- Request-to-exit (REX) switch integration
Mortise locks are widely used in:
Because the lock is built into the door, proper prep is critical. Architects should specify mortise lock type early, along with door and frame details.
Mortise Locks vs. Cylindrical Locks: Choosing the Right Fit
Both mortise and cylindrical locks have a place in commercial construction. Cylindrical locks remain a practical choice for many openings, they install quickly and work well where security demands are moderate.
For high-traffic or high-security openings, mortise locks are often the stronger long-term investment. Advances in door prep machinery have reduced the cost gap between mortise and cylindrical preps. At the same time, ADA lever requirements pushed cylindrical lock prices up as manufacturers added reinforcements to handle the extra leverage. Today, the price difference between the two is often smaller than specifiers expect.
When durability, repairability, and long service life are priorities, mortise locks are worth specifying. PDQ offers both options to fit the needs of any opening.
Mortise Lock with Key vs. Electrified Options
A mortise lock with key works well when basic security is enough. These locks suit offices, storage rooms, and interior and exterior doors.
Mechanical mortise locks are often used when:
- Access needs to stay simple
- No monitoring is required
Electrified mortise locks support access control systems. They allow doors to lock or unlock by signal.
Electrified options are often required when:
- Card readers or keypads control entry
- Doors need audit trails
- Openings must tie into security systems
Architects should specify electrified mortise locks when access control is planned. Coordinate early with security and electrical teams.
Mortise Lock Dimensions & Mortise Prepped Doors: Avoiding Costly Mistakes
Clear mortise lock specifications depend on accurate dimensions and proper door prep. Most field issues trace back to missing or vague details. Architects can avoid rework by calling out exact requirements early.
Standard Mortise Lock Dimensions to Call Out
Mortise locks rely on tight tolerances. Small errors can stop installation. Note that latch and deadbolt centerline dimensions vary from manufacturer to manufacturer, always confirm these align with the strike before specifying or ordering.
Architects should specify:
- Case size to match the door edge pocket
- Backset to align trim and latch location
- Door thickness range supported by the lock
- Faceplate and strike dimensions for frame prep
- Handing to match door swing
- Latch and bolt types to suit the lock function
These details affect fit, security, and code compliance. Leaving them open invites RFIs.
Why "Mortise Prepped Doors" Must Be Explicitly Specified
Not all doors arrive ready for mortise locks. Some ship with blank edges. Architects should state when mortise prepped doors are required.
Key risks include:
- Field prep adds labor and cost and can negate fire ratings on the door/frame
- Inaccurate prep can weaken the door
- Inspection delays may follow
Retrofits carry higher risk. Re-prep often means pulling doors off schedule.
Coordinate early with door and frame suppliers. Confirm prep matches the lock series.
How PDQ's MR Series Aligns with Industry Standards
The PDQ MR Series is designed around common mortise preps. It fits standard commercial door and frame conditions.
This approach helps:
- Reduce custom prep requests
- Simplify coordination across trades
- Support smoother substitutions when needed
Well-defined mortise lock dimensions help projects move faster and install cleaner.
Specifying PDQ Mortise Locks: Mechanical vs. Electrified Applications
Start with the opening's needs. Decide if access control is required. Then confirm door prep, function, and code items. Clear mortise lock specifications reduce RFIs and speed submittals.
When to Specify the PDQ MR Series Mechanical Mortise Lock
Best-fit applications
The PDQ MR Series suits high-traffic openings without access control. These doors still need strength and long service life. Common uses include schools, offices, healthcare, and public buildings. Interior and perimeter doors often use a mortise lock with key when access needs are simple.
When to specify
Architects should specify the MR Series when access control is not required, durability is a priority, and standard mortise prepped doors are planned.
Key specification elements
List key elements in the spec so installers have no doubts:
- Function type, such as classroom, office, or storeroom
- Trim and lever style to match the design
- Finish that meets wear and cleaning needs
- Cylinder or core type for the keying plan
Also include handing, supported door thickness, and any fire rating. These items affect fit, schedule, and inspections.
Certifications and code compliance (MR)
The MR Series carries the following listings and compliance items:
- UL listed for 3 hours on single doors up to 4'0" x 8'0"
- UL10C 3-hour, single doors up to 48" x 96", active leaf in pairs up to 96" x 96"
- ANSI/BHMA A156.13 Grade 1, operational and security
- Florida HVHZ approval, PDQ Product Approval FL 21376, design load ±70.0 PSF for a 3' x 7' door
- Complies with ADA and ICC/ANSI 117.1
- J Wide Escutcheon Trim meets UFGS 08 71 00, August 2008
Clear documentation helps installers match hardware to each opening and avoid rework.
When to Specify the PDQ MR199 Electrified Mortise Lock
Best-fit applications
Some openings need more control than a key. The MR199 supports access control, status monitoring, and remote commands. It fits facilities with strict security policies and managed entry points.
When to specify
Architects should specify the MR199 when readers, keypads, or controllers manage access. It is also a fit when the owner needs audit logs or door status.
Key electrification decisions to coordinate
Electrified hardware adds coordination. Architects should coordinate:
- Fail-safe or fail-secure operation by door use and code
- Power needs, including voltage and current
- Wiring path through the door and frame
- Power transfer selection from frame to door
- Compatibility with readers, controllers, and monitoring devices
Certifications and code compliance (MR199)
The MR199 includes all MR certifications, plus added listings for electrified use:
- ANSI/UL10C and CAN/ULC-S104 fire listings up to 3 hours
- Listed for Fire Exit Hardware, where applicable
- Assembled in the United States with U.S. and foreign materials, meets Buy American Act requirements as a COTS product
Specification advantage
The MR199 uses standard mortise preps, which cuts rework and eases door coordination. Accurate mortise lock dimensions and clear system notes help installs go smoothly. Coordinate early with hardware, door, electrical, and security teams.
How to Specify PDQ Mortise Locks Correctly in Division 08
Clear mortise lock specifications keep projects on track. They also cut RFIs and change orders. Use the guide below to write clean Division 08 language that installers can follow.
Correct Placement in Division 08
Place all PDQ mortise locks in Division 08, Section 08 71 00 [Door Hardware]. Group items by opening type and function so schedules read clean.
Architects should specify hardware sets that match the door schedule. Keep naming consistent across drawings, specs, and submittals.
Model Naming and Schedule Clarity
List the exact product in both the spec and schedule. Avoid vague terms. Architects should include:
- Model: PDQ MR or PDQ MR199
- Function designation for each opening
- Fire rating and door location
- Electrification notes for MR199 doors
Avoid "or equal" without performance and certification limits. Tie equals to required listings and grades to protect intent.
Required Specification Details
Call out details that installers and inspectors need. This reduces questions and delays. Include:
- Lock type: mechanical or electrified
- Mortise lock dimensions and door prep
- Trim, finish, and handing
- Power, current draw, and wiring notes for MR199
- Code and certification references for each opening
Architects should specify mortise prepped doors where needed. Coordinate door and frame preps with the hardware set.
Preventing Costly Substitutions
Substitutions can derail the schedule if not managed. Set clear limits. Architects should:
- Cite required certifications, like UL10C and ANSI/BHMA Grade 1
- Require submittals that match HVHZ, UL fire listings, and grades
- Note compatibility with standard mortise prepped doors
Well-written mortise lock specifications protect the design and budget. Coordinate early with hardware, door, and electrical teams for smoother installs.
Write It Right the First Time: Checklist + PDQ Support
Strong mortise lock specifications prevent delays and rework. Use this quick checklist:
- Lock type: mechanical or electrified
- Function for each opening
- Mortise lock dimensions that match the door and frame
- Mortise prepped doors shown in the door schedule
- Trim and finish, aligned with use and design
- Handing and door thickness range
- Latchbolt position monitoring and REX switch requirements (where applicable)
- Power and monitoring details for electrified doors
Architects should specify clear details in Division 08. Coordinate with door, frame, electrical, and security teams.
Explore the product pages or contact PDQ for assistance.
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MR Series: https://www.pdqlocks.com/products/mr-mortise-lock
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MR199 Series: https://www.pdqlocks.com/products/mr199-electrified-lockset
Get a clean, confident PDQ mortise lock spec on your next project.
