What This Article Covers and Who It Helps
Specifying locksets for apartment building entrances is not the same as picking a lock for an office door. Multi-family residential entrances carry overlapping obligations: tenant security, emergency egress, building code compliance, and day-to-day convenience for dozens of occupants who never read a hardware schedule. This guide is written for property managers, commercial contractors, and architects working on new multi-family construction or renovation projects who need to understand which lock functions apply, where each belongs, and what to watch for before the hardware schedule ships.
What Is an Apartment Entrance Function Lockset?
An apartment entrance function lockset -- sometimes called an apartment function or public toilet function in BHMA/ANSI terminology (ANSI F88) -- is a cylindrical or mortise lock specifically configured for multi-family residential applications. The defining behavior: the outside lever is always locked by default and requires a key for entry, while the inside lever is always free, ensuring occupants can exit at any time without a key or special knowledge. A secondary feature common to this function is that the outside lever can be locked or unlocked by a turn of the inside thumbturn, allowing the occupant to control access mode from inside the unit.
This combination -- controlled entry, unconditional egress -- is the core requirement for a unit entry door in most jurisdictions, and it is what separates apartment function from storeroom function (which has no thumbturn control) or office function (which requires a key to re-lock from outside).
The Three Doors That Confuse Most Hardware Schedules
A typical multi-family project has at least three distinct entry points that each demand a different function. Getting them mixed up is one of the most common errors on a residential hardware schedule.
1. The Unit Entry Door
This is the apartment entrance function door described above. Key requirements:
- Outside lever always locked -- key required for entry
- Inside lever always free -- no key, no twist, no delay for egress
- Inside thumbturn (on some configurations) lets the occupant lock or unlock the outside lever from inside -- useful when expecting guests or a maintenance crew
- Deadbolt or auxiliary deadlatch strongly recommended for security depth; many jurisdictions and many local codes require it
For Grade 1 heavy-duty applications -- high-rise, high-cycle buildings -- the Corbin Russwin CLX3372 (Apartment/Public Toilet, ANSI F88) is a well-regarded option in the CLX3300 Grade 1 cylindrical line. For standard-duty multi-family where budget is a factor, the Corbin Russwin CL3800 family covers the same function at Grade 2, which is appropriate for most low-to-mid-rise residential corridors.
2. The Common Vestibule or Lobby Entrance
This is the building entrance -- the door between the public sidewalk and the controlled lobby. It typically requires:
- A heavy-duty latchset with an auxiliary deadlatch bolt to resist shimming or loid attacks
- Outside cylinder operated by a tenant key (in many jurisdictions, this key must not also open the unit door -- a separate keyway is required)
- Electric strike or electric latch retraction tied to an intercom or access control system for remote release
- Adequate illumination at the entrance (some codes specify minimum foot-candle levels at floor level)
The NYC Building Code (Section 1008.4.1) is illustrative of the national trend: building entrance doors must carry heavy-duty locksets with auxiliary latch bolts, and the tenant key for the entrance must be on a separate keyway from the apartment key. Many other jurisdictions follow similar logic even where not explicitly codified.
3. Stairwell and Common-Area Doors
Stairwell re-entry doors in multi-family buildings are a frequent code trap. In many high-rise applications, stair doors must allow re-entry from the stair side -- meaning the hardware must default to an unlocked or passage condition on the stair side while remaining controlled from the corridor side. An electrified fail-safe function (power removed = unlocked for re-entry) is the typical solution here, often tied to the fire alarm system. These doors are not apartment entrance function doors -- mixing the functions creates a life-safety problem.
Function vs. Grade: Both Matter on the Hardware Schedule
Specifying the correct function (apartment, storeroom, passage, etc.) is only half the equation. Grade determines whether the lock will survive the cycle life and abuse load of multi-family use.
- ANSI/BHMA Grade 1 (Series 4000 for cylindrical) -- required for high-traffic unit entries, exterior building entrances, and any door in a high-rise or large complex. Grade 1 locksets from preferred lines like Corbin Russwin, Sargent, and Hager are rated for higher cycle counts and provide greater resistance to forced entry.
- ANSI/BHMA Grade 2 (Series 4000) -- acceptable for lower-traffic residential applications, light-duty interior common-area doors, and value-engineering situations on small multi-family projects. Not recommended for exterior building entrances or primary unit entry doors in large complexes.
Key Control: The Detail That Gets Skipped Until There Is a Problem
Multi-family buildings with a shared entrance key and a separate unit key create a two-keyway system that must be planned before the cylinders are ordered. Common failures:
- Entrance and unit cylinders ordered to the same keyway -- tenants can open neighbor units with the wrong key
- No master key hierarchy defined -- maintenance staff carry a ring of individual keys instead of a building master
- No construction master key specified -- contractor keys are never removed from service
- Restricted keyway not specified -- any hardware store can cut a duplicate of the building entrance key
Building entrance cylinders in particular benefit from a restricted keyway -- a patented, limited-distribution key profile that prevents unauthorized duplication. This is a separate conversation from the lock function, but it belongs on the same hardware schedule page.
Where Electrified Hardware Fits Into the Multi-Family Entrance
Modern apartment buildings increasingly combine a mechanical apartment-function lockset on the unit door with electrified access control at the building entrance. The most common configuration:
- Electric strike at the lobby entrance -- released by an intercom, key fob, or mobile credential; the mechanical latchset handles the security in the unpowered state
- Fail-secure electric strike -- door stays locked on power loss (appropriate for a secured lobby entrance)
- Power transfer hinge or EPT -- required when the electrified component is in the door leaf rather than the frame
- Door position switch and request-to-exit device -- required for access control integration and audit trail
The mechanical unit-entry lockset typically remains fully mechanical -- the unit entry is not a common access-control integration point unless the project specifies electronic locks at the unit level.
Hardware That Completes the Apartment Entrance Assembly
The lockset does not work alone. A complete unit entry hardware set typically includes:
- Hinges -- Grade 1 ball-bearing or standard commercial hinges from lines like Hager, McKinney, or Rockwood, matched to door weight and frequency
- Door closer -- required in corridors for fire-rated assemblies; preferred lines include Hager, Norton, and Corbin Russwin/PDQ for cycle-life reliability
- Threshold and door bottom seal -- sound and smoke control between unit and corridor; Pemko and Rockwood cover most configurations
- Latch protector or strike guard -- on unit entries where the frame gap is exposed, a latch guard discourages shimming attacks without replacing the lock
- Door viewer (peephole) -- standard on most residential unit entries; Rockwood and similar lines supply these as a catalog item
Specifying Right the First Time
Before the hardware schedule is finalized on a multi-family project, confirm these five points with your hardware supplier:
- Is the building entrance key on a separate keyway from the unit entry key?
- Is the unit entry door function truly apartment function (F88 or equivalent) and not storeroom or office function?
- Are Grade 1 locksets specified wherever cycle life and security demand it?
- Is the key control hierarchy -- construction master, building master, unit key, entrance key -- defined before cylinders are ordered?
- Is electrified hardware at the lobby entrance coordinated with the access control and fire alarm systems before rough-in?
DoorwaysPlus carries cylindrical and mortise locksets in apartment entrance and companion functions from Corbin Russwin, Sargent, Hager, and PDQ, along with the full complement of hinges, closers, seals, and keying accessories to complete a multi-family hardware set. If you are working through a schedule or need a competitive quote on a specific project, the DoorwaysPlus team can help you match function, grade, finish, and keyway before anything ships.