What ANSI A156.13 Actually Governs -- and Why It Matters at Every Opening
If you are writing a hardware schedule, reviewing submittals, or replacing a failed lock body in the field, the ANSI/BHMA A156.13 standard is the single most important reference for mortise locksets. This post explains what the grade tiers and function code numbers mean in practical terms, how they map to real building types, and what to watch for when a spec or a field replacement goes wrong. It is written for commercial hardware specifiers, facility maintenance teams, and construction managers who need to translate standard language into correct product decisions.
What Is ANSI/BHMA A156.13?
ANSI/BHMA A156.13 is the published performance standard for mortise locks and latches in commercial construction. It is developed by the Builders Hardware Manufacturers Association (BHMA) and approved by the American National Standards Institute (ANSI). The standard defines:
- Operational grade tiers (how many cycles a lock must survive)
- Security grade tiers (resistance to forced entry and manipulation)
- A numbered function series (Series 1000) that describes exactly how the latch, deadbolt, and levers behave on each side of the door
- Physical construction requirements -- case gauge, latchbolt throw, deadbolt throw, strike dimensions, and more
A mortise lock body is mortised into the door edge rather than surface-mounted or bored through the face. That recessed installation is what gives it the structural advantage over cylindrical hardware on high-cycle or high-security openings.
Grade 1 vs. Grade 2 vs. Grade 3: The Cycle and Security Tiers
ANSI A156.13 carries both an operational grade (durability) and a security grade (resistance to forced entry). In most commercial applications you will see these two grades listed together on a product submittal. Here is how the tiers break down in plain terms:
- Grade 1: The commercial and institutional benchmark. Products certified to Grade 1 must survive a minimum of 1,000,000 operational cycles. Security Grade 1 adds requirements for deadbolt throw, anti-friction latch construction, and resistance to physical attack. This is the minimum grade appropriate for schools, hospitals, retail storefronts, and any high-traffic opening.
- Grade 2: An intermediate tier, typically found in light commercial or multi-family residential applications. Fewer cycle requirements and reduced security thresholds.
- Grade 3: Residential/light duty. Rarely specified in new commercial construction and not appropriate for fire-rated or life-safety openings.
When a spec reads ANSI/BHMA A156.13 Series 1000, Grade 1, it is requiring the full commercial tier on both operational and security dimensions. Substituting a Grade 2 product is a submittal rejection waiting to happen -- and a liability problem in a school or healthcare corridor if the hardware fails in service.
Some Grade 1 mortise locks carry independent UL listing for 3-hour fire doors as well. That UL listing is separate from the ANSI grade and must be confirmed on the product data sheet when the opening is fire-rated.
The Series 1000 Function Codes: Reading F-Numbers on the Schedule
The most misunderstood part of A156.13 for field teams and newer specifiers is the function numbering system. Each function defines the exact behavior of the lock -- which side is always free, which side requires a key or thumbturn, and how the deadbolt and latch interact. Manufacturers assign their own model numbers, but they must map to a standardized ANSI function if they claim A156.13 compliance.
Here are the most common functions you will encounter on a commercial hardware schedule:
High-Traffic Passage and Entry Functions
- F01 -- Passage Latch: Latch retracts by lever either side. No locking. Used in corridors, mechanical rooms, and interior doors where free passage is always required.
- F04 -- Entrance/Office: Outside lever locked or unlocked by key; inside lever always free. Standard for private offices, suite entries, and administrative areas.
- F05 -- Classroom: Outside lever locked or unlocked by key from outside only; inside lever always free. A critical distinction -- the key is used in the outside cylinder, not from inside. Locking requires the teacher or staff member to step into the corridor. (This is a recurring compliance issue in school lockdown procedures -- see our earlier post on classroom security hardware.)
- F07 -- Storeroom: Outside lever always rigid (key required to enter); inside lever always free for egress. Used on storage rooms, electrical closets, server rooms, and similar low-traffic secure spaces.
Privacy and Institutional Functions
- F13 -- Dormitory/Entrance: Outside lever deadlocked by key from outside; inside thumbturn releases deadbolt; inside lever always free. Common in dormitories, apartment entries, and some healthcare patient rooms.
- F19 -- Privacy: Inside thumbturn locks outside lever; emergency outside access via small release tool. Typical for private restrooms, single-occupancy patient rooms, and hotel baths.
- F14 -- Store Door/Utility: Latch by lever either side; deadbolt by key either side. No emergency egress provision -- do not use where life safety egress is required.
Deadlock-Only Functions (No Latch)
- F16 -- Double Cylinder Deadlock: Deadbolt by key either side. Use with caution on egress paths -- occupants must have a key to exit.
- F17 -- Cylinder and Thumbturn Deadlock: Key outside, thumbturn inside. The most common auxiliary deadlock function.
- F18 -- Single Cylinder Deadlock: Key outside only; no inside operation.
Physical Construction Requirements Worth Knowing
Beyond grade and function, A156.13 sets minimum physical parameters that affect compatibility and installation. A few that come up often in the field:
- Latchbolt throw: 3/4" minimum projection -- the bolt must fully engage the strike keeper.
- Deadbolt throw: 1" minimum projection for Grade 1 locks.
- Standard backset: 2-3/4" is the commercial standard. Verify before ordering on older buildings or narrow-stile aluminum doors that may use a different backset.
- Face plate: Typically 1-1/4" wide; should be field-adjustable from flat to 1/8" bevel to match the door edge preparation.
- Strike: ANSI A115.1 strike prep is the coordinating door prep standard -- confirm the frame and door are prepped to match the lock you are ordering.
Preferred Mortise Lock Lines at DoorwaysPlus
DoorwaysPlus stocks and sources Grade 1 A156.13 mortise locks from manufacturers known for stable product lines and service-friendly designs -- meaning parts and trim are interchangeable across model years and components can be replaced at the lock level rather than requiring a full door prep rework. Lines we recommend for commercial projects include Sargent, Corbin Russwin, Accentra (formerly Yale), PDQ, and Accurate for specialty applications. Our team can cross-reference your existing prep and hardware schedule to confirm compatibility before you order.
Quick Spec Checklist Before You Submit
- Confirm ANSI/BHMA A156.13 Series 1000 Grade 1 is specified -- not just "Grade 1 cylindrical"
- Identify the correct F-number function for each door type on the schedule
- Verify UL fire listing if the opening is rated
- Confirm backset, face width, and door thickness match the lock body being quoted
- Check that the strike package matches the frame prep (wood frame vs. hollow metal vs. aluminum)
- For electrified openings, confirm the mortise lock case has provisions for the required electrical option (latchbolt monitor, electric latch retraction, fail-safe or fail-secure solenoid)
Getting the function code wrong is one of the most common and most expensive specification errors in commercial door hardware. A storeroom function on a classroom door or a passage function on a secure corridor door creates both security gaps and code compliance problems. When in doubt, call us before the submittal goes in -- not after the hardware ships.
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