What This Article Covers and Who It Helps
Hotel function locksets and double-locking deadbolts are a specific class of hardware that confuses specifiers, contractors, and facilities teams alike. If you are working on a lodging project, a multi-family building, a dormitory, or any application where a guest or occupant needs automatic deadbolt protection the moment the door closes, this guide explains how the mechanism works, how it differs from other common functions, and what to watch for when specifying or ordering.
What Is Hotel Function (BHMA/ANSI F17)?
Hotel function, designated F17 in the BHMA/ANSI lock function classification system, is a mortise lockset function designed for guestroom entry doors. Here is how it behaves:
- Outside: Locked at all times. Entry requires a key, credential, or card.
- Inside thumbturn: The occupant can throw a deadbolt from inside for privacy and added security.
- Auto-deadlock: When the door closes, the auxiliary deadlocking bolt (sometimes called the auto-deadlatch or deadlocking plunger) automatically engages, preventing the latch from being slipped with a card or tool from outside.
The combination of a key-controlled exterior, a manually operated interior deadbolt, and an auto-deadlocking latch is what sets F17 apart from simpler functions like storeroom (F07/F08) or office (F05).
Double-Locking vs. Auto-Deadlocking: A Practical Distinction
These two terms are sometimes used interchangeably in the field, but they describe different things:
- Auto-deadlocking (deadlocking plunger): A secondary bolt on the latchbolt assembly that engages the strike automatically when the door closes, blocking forced retraction of the latch from outside. This is a feature of most Grade 1 mortise locksets regardless of function.
- Double-locking (interior deadbolt throw): A separate full deadbolt, engaged by the occupant from inside using a thumbturn, that projects a full bolt throw independent of the latch. This is the layer the occupant controls deliberately.
In a true hotel function mortise lock, both layers are present. The door is auto-secured on closing, and the occupant can add a second independent deadbolt for maximum privacy.
Where Hotel Function Hardware Is Typically Required or Specified
While building codes do not always mandate a specific lock function by name, the security expectations of certain occupancy types drive specifiers toward F17 or equivalent configurations:
- Hotels and motels: The obvious application. Brand standards from major flags often require electronic hotel function locksets with audit trail capability.
- Dormitories and student housing: Residence hall directors and campus facility managers frequently specify hotel function to give occupants interior deadbolt privacy without compromising front-desk override capability.
- Extended-stay and senior living: Similar reasoning -- resident privacy balanced with staff access in emergencies.
- Multi-family residential entry doors: In apartment construction, some designers use a dormitory function (F13) or hotel function to give residents both key entry and interior thumbturn deadbolt control in a single mortise unit.
The Cylinder Behind the Function: Why Hotel Cylinders Are a Separate Order Item
A detail that catches contractors and estimators off guard: hotel function mortise locks often require a dedicated hotel function cylinder, not a standard cylinder from the same manufacturer line.
The hotel cylinder typically adds a second keyway or a special cam configuration that allows a housekeeping key or emergency master to retract the interior deadbolt from outside -- overriding the occupant's thumbturn -- when the room is unoccupied. This override function is what separates a hotel cylinder from a standard mortise cylinder.
When sourcing mortise locksets for hotel applications, confirm with your hardware supplier whether the hotel function cylinder ships with the lockset body or must be ordered separately. This is a common schedule error that delays opening day.
Specifying Hotel Function: What to Check Before the Schedule Ships
When writing or reviewing a hardware schedule for hotel function openings, verify each of the following:
- Function code: Confirm F17 (or manufacturer-equivalent) is listed, not F13 (dormitory) or F05 (office), which look similar but behave differently.
- Cylinder type: Hotel function cylinder ordered and keyed appropriately for the master key system, including emergency override.
- Handing: Mortise locksets are handed. Confirm handing on the schedule matches the door swing in the field.
- Backset: Standard mortise backset is 2-3/4 inches. Confirm the door edge and prep match.
- Strike: A full-lip strike with a strike box is recommended to provide full bolt projection clearance for both the latch and the deadbolt.
- Electrified variant: Many hotel applications today pair hotel function trim with an electrified mortise body for electronic access control (RFID, mobile credential). If so, coordinate the power transfer hinge circuit count and access control wiring before the door is prepped.
Preferred Hardware Lines for Hotel and Double-Locking Applications
For hotel function mortise locksets and auxiliary deadbolts on lodging and multi-family projects, DoorwaysPlus stocks and recommends lines from Sargent, Corbin Russwin, Accentra (formerly Yale), and PDQ -- all of which offer stable, service-friendly product platforms well suited to repeat-replacement and rekeying environments common in hospitality. These lines carry Grade 1 ANSI/BHMA certifications and support a range of cylinder options including large format interchangeable cores (LFIC) for properties that rekey frequently.
For auxiliary deadbolts used as standalone secondary locks on lodging or multi-family doors, Accentra's D-series and Heritage-series deadbolts provide single-cylinder and double-cylinder options in both Grade 1 and Grade 2 configurations to match the security tier of the project.
A Note on Electronic Hotel Function
The shift toward electronic access in hospitality has not eliminated the mechanical hotel function -- it has layered on top of it. Many modern hotel mortise platforms retain the mechanical F17 behavior (auto-deadlatch, interior thumbturn deadbolt) while adding an electrified chassis that interfaces with a property management system. The occupant still throws the interior deadbolt manually; the electronic layer controls credential-based entry and audit logging. When specifying these openings, treat the mechanical function and the electrical function as two separate line items on the hardware set.
Get the Right Hardware for Your Project
Hotel function and double-locking hardware sits at the intersection of occupant privacy, security, and master key management. Getting the function code, cylinder type, and electrification right before the schedule ships saves costly field changes. DoorwaysPlus carries Grade 1 mortise locksets, hotel cylinders, auxiliary deadbolts, and electrified lock platforms from preferred manufacturers. Our team can help you match the right hardware to your opening before the order goes out.
Visit DoorwaysPlus.com to shop mortise locksets, hotel function hardware, and auxiliary deadbolts -- or contact us for specification support on your next lodging or multi-family project.