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Master key system design and management for multi-site businesses

A master key system lets each person carry one key that opens only the doors their role requires, while managers keep access to every area. Facility First manages the design, rekeying and records for these systems across every location through vetted local locksmiths.

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What a master key system involves

A master key system is a planned arrangement of locks and keys in which a single key can operate more than one lock, and different keys open different groups of doors. At a typical store or office the levels look like this:

Change key. Opens one lock or one group of identical locks, such as a stockroom or an office.
Master key. Opens every lock in a defined group, such as all back of house doors at one location.
Grand master key. Opens every lock under two or more master groups, for example the whole building.
Higher levels. Large portfolios sometimes add a level above the grand master. Each added level means more keys that open more doors.

In a pin tumbler cylinder, master keying is done by adding extra pin segments so that more than one key cut pattern will turn the plug. The locksmith calculates the cut patterns (the bitting) for every key in the system from a single plan, so that change keys do not accidentally open each other’s doors. That plan, the keying schedule, is the most sensitive document in the system.

Common design choices include:

Restricted or patented keyways, where blanks are available only through an authorized dealer, so keys cannot be copied at a hardware counter.
High security cylinders for doors that protect cash, high value stock or records.
Interchangeable cores, which let the core of a cylinder be removed with a control key and replaced, instead of rekeying the lock in place, useful at sites with frequent staff turnover.
Construction keying, where a temporary key used during a fit-out is cancelled when the permanent keys are first used.

Standards and requirements for master keying

No single law sets how a business must design its key system, but several standards and regulations apply to the work.

Keying system design. ANSI/BHMA A156.28, Recommended Practices for Mechanical Keying Systems, is written for building owners and security professionals. The Builders Hardware Manufacturers Association describes it as covering system design criteria “to establish and maintain a secure keying system” and good practices for effective key management.
Cylinder performance. ANSI/BHMA A156.5 covers cylinders for locks; BHMA states that Grade 1 cylinders must pass a 40,000 cycle test.
High security cylinders. ANSI/BHMA A156.30 rates high security cylinders on key control, destructive tests such as drilling, and resistance to picking. Its key control category looks at limiting unauthorized keys through features such as key blank control.
Exit doors. OSHA 29 CFR 1910.36(d)(1) states that employees must be able to open an exit route door from the inside at all times without keys, tools or special knowledge. Any rekey or lock change on an exit door has to preserve that.
Fire doors. NFPA 80 calls for fire door assemblies to be inspected and tested at least annually, with a signed written record kept for the authority having jurisdiction, and lists among the inspection items that no field modifications have voided the label and that no open holes exist in the door or frame. A cylinder or lock swap on a labeled fire door has to use hardware that keeps the assembly compliant.
Licensing. Many jurisdictions license locksmith work. California requires a locksmith company license and registration of locksmith employees, with background checks. New Jersey licenses individuals and businesses that modify, recombine, repair or install mechanical locking devices for pay. Requirements vary, and Facility First dispatches only providers that hold the licenses each location requires.

The local fire code official, the building owner or landlord, and the property’s insurer can each set further rules for which doors may be keyed together and who may hold which keys.

Preventive maintenance schedule for master key systems

A master key system loses its value as soon as the records stop matching the keys in circulation. Planned checks keep cylinders working, keep the key schedule current and produce the records an insurer or landlord will ask for after a loss. Fire door hardware has a published inspection interval; other key tasks follow ordinary program defaults.

Task	Recommended frequency	Basis
Inspect and test fire door assemblies, including latching hardware, with a signed written record	At least annually	NFPA 80 (2007 edition), 5.2.1
Confirm exit route doors open from the inside without keys, tools or special knowledge	After every rekey or cylinder change	Requirement: OSHA 29 CFR 1910.36(d)(1). Frequency: Facility First program default, adjusted per site
Key audit: reconcile every issued key against the current key holder list	Quarterly	Facility First program default, adjusted per site
Rekey or recore every lock the lost key operated	Each time a key is lost, stolen or not returned	Facility First program default, adjusted per site
Lubricate and test cylinders and check key operation	Twice a year, or at the interval in the manufacturer’s instructions	Manufacturer instructions; Facility First program default, adjusted per site
Review the keying design against the current floor plan and roles	Annually, and after any remodel or change of use	Facility First program default, adjusted per site
Update the keying schedule and door list	After every rekey, recore or lock change	Facility First program default, adjusted per site
Confirm control keys and grand master keys are accounted for	Quarterly, with the key audit	Facility First program default, adjusted per site

The authority having jurisdiction, the manufacturer and the property’s insurer can require more frequent service, and each location’s schedule is set in its program and recorded on every visit.

Signs a master key system needs work

A master or grand master key is lost, or a person who held one leaves without returning it.
Nobody can produce a current list of who holds which keys.
Change keys open doors they should not, which can happen after years of unplanned additions.
Cylinders are hard to turn, keys stick, or keys are wearing thin.
A remodel, new tenant or change of store layout has altered which doors need to be grouped together.

Records to keep

Keying schedule. Every door, its cylinder, its key symbol and the levels that operate it. Stored securely with access limited to named people.
Key issue log. Key number, holder, date issued, date returned and the holder’s signature.
Rekey and recore history. Date, doors affected, reason and the provider who did the work.
Authorized ordering list. The people allowed to order new keys or blanks under a restricted keyway agreement.
Fire door inspection records. The signed annual record NFPA 80 calls for, kept for the authority having jurisdiction.
Photos. Close-out photos of each door and cylinder after the work.

How Facility First runs master key work across a portfolio

Request. A rekey, lost key report or new design is submitted through the platform or by phone.
Triage. Facility First confirms scope, the doors affected, any fire door or exit door involved, and whether the keyway is restricted.
Dispatch. A vetted locksmith licensed for the location’s market receives the work order with the door list.
Completion. The provider rekeys or recores, tests each door, confirms exit doors still open from the inside, and closes out with photos.
Verification and invoice. The work is checked against the request, the keying schedule is updated, and the job is invoiced in one format.

Lost key rekeys within the client’s approval limit proceed directly. A new system design or a portfolio-wide rekey is quoted for approval first. Where a lost master key leaves a location unsecured overnight, McCray can post an officer until the work is complete. See Security by McCray.

What affects the cost of a master key system

Number of doors and cylinders, and how many levels the design has
Restricted or patented keyway versus a standard keyway
High security or interchangeable core cylinders
Whether a lost key sits high in the system, which means more cylinders to change
Fire rated doors that need listed replacement hardware
After-hours scheduling to avoid trading hours

Approval limits set by the client decide what proceeds automatically and what is quoted first.

Master key systems for retail stores, restaurants and offices

Retail stores. Back of house, stockroom, cash office and fitting room doors usually sit in separate groups, with store managers on a master key and district staff on a grand master. Work is scheduled before opening or after closing.
Restaurants. Walk-in coolers, dry storage, liquor rooms and offices are often keyed separately so that each shift holds only what it needs.
Offices. Tenants, building management and cleaning crews each need different access. Lease terms often set what the landlord’s master key must open.

Locations that hold safes keep safe combinations outside the key system entirely. See Safe locksmith.

Frequently asked questions

What is the difference between a master key and a grand master key?

A master key opens every lock in one group, such as all doors at one store. A grand master key opens every lock across two or more of those groups.

What happens if a master key is lost?

Every lock that the lost key could open should be rekeyed or recored, and the keying schedule updated. A lost grand master key affects more locks than a lost change key, which is why high level keys are issued to as few people as possible.

Can an existing set of locks be converted to a master key system?

Usually yes, if the cylinders accept master keying. A locksmith surveys the doors, designs the levels and rekeys the cylinders to the new plan, replacing any that cannot be converted.

Do restricted keys stop copying?

Restricted and patented keyways are designed to limit who can obtain key blanks, and high security cylinders are rated in part on key blank control under ANSI/BHMA A156.30. The control lasts only as long as the list of people allowed to order keys is kept current.

How often should a master key system be audited?

Facility First programs reconcile issued keys quarterly and rekey whenever a key is lost or not returned. NFPA 80 separately calls for fire door assemblies, including latching hardware, to be inspected at least annually.

Does a lock change affect fire doors or exit doors?

It can. Exit route doors must still open from the inside without keys or special knowledge, and replacement hardware on a labeled fire door must not void the label.

Sources

Put every key, lock and rekey on one record across every location.