Master Key Systems for Small Businesses

What a master key system is

In an ordinary set of locks, every door has its own key and nothing else opens it. A master key system adds levels on top. Each lock still has its own key (often called a change key), but the locks are also set up to accept a master key for their group, and sometimes a grand master key that opens every group. Large organisations can have several levels, arranged like a family tree.

ABLOY describes the same structure: individual keys for each lock, a master key for a group, and on larger systems several masters under one grand master. ASSA ABLOY South Africa's Mzansi cylinder range, for example, is offered keyed to differ, keyed alike, or in master key systems of up to 2,000 cylinders per master, with grand master systems of up to ten sub-master groups.

A worked example

Picture a small distribution business with a warehouse and an office block on one site.

The dispatch clerk carries one key that opens dispatch and nothing else. The operations manager carries one key for every warehouse door. The owner carries one key for the whole site. Nobody walks around with a ring of twenty keys, and a leaving staff member's key opens only what it always did.

Does your business actually need one?

A master key system makes sense when:

• you have more than a handful of lockable doors, and different staff need different combinations of them;
• managers are carrying heavy key rings and handing keys over at every shift change;
• you share a site, such as a unit in a business park, and want clear separation between areas;
• you expect to add doors, units or staff.

It may be overkill when a few people need access to every door. In that case keyed-alike locks give one key for everything without a hierarchy to manage.

There's also a security trade-off. Master-keyed locks accept more than one key, and as Wikipedia's overview of master keying notes, it generally reduces overall security compared with locks that each take a single key. Losing a master key is also more serious than losing one door key. Businesses that need tighter control sometimes keep their most sensitive rooms off the system or look at electronic access control instead.

Design it on paper before anyone touches a door

The planning is the system. ABLOY, for example, codes every master key system centrally and works from a site survey and a schematic. Before you speak to a supplier, put together:

• A door schedule: every lockable door, gate and roller door, numbered, with what's behind it.
• A role list: each job, and which doors that job genuinely needs.
• The groups: which doors belong together under a master, such as warehouse, office or yard.
• Exclusions: any door that should not open with any master.
• Growth: extra units, a second building or more staff. A system planned with spare capacity is far easier to extend.
• Existing hardware: lock types and sizes on each door, so the new cylinders or locks fit.

If your unit is in a business park with its own gate or gatehouse, that access is run separately from your key system. Note it on the schedule, but don't plan your groups around it.

Key control is what makes it work

A master key system without key control is just a convenient way to lose track of keys. The pieces that matter:

• Restricted or patented key profiles. ASSA ABLOY explains that patents on a key profile let the maker control who may produce keys, restricting copies to authorised partners, and make blanks harder to obtain. Patents expire, so check how long the protection on your profile runs. Mul-T-Lock, for instance, sums up its card-controlled approach as "no card, no cut".
• Registration and authorisation. ABLOY describes key control levels where extra keys are issued only against a registration card, or only on a signed order from staff whose signatures are on file, with keys numbered in sequence so each one can be traced.
• A key register. Who holds which key, its number, the date it was issued, and a signature. Check it against reality from time to time, and collect keys when people leave.
• Few masters. Keep the number of master and grand master keys as low as you can, and store spares securely, not on a hook in the office.

The same thinking applies to safe codes. If your business safe has several users, our article on forgotten safe codes explains how code levels work.

When a key goes missing or someone leaves

Record the loss in the key register, and let your insurer know if your policy expects it. If a loss coincides with a break-in, damaged doors and locks need attention first.

Where a mobile locksmith fits in

We don't cut or copy keys, and we don't supply keys for registered systems. Extra keys and cylinders keyed to an existing master system come through the supplier that holds the system records and follows the maker's authorisation rules, which is exactly what protects you.

What we do for businesses is the hands-on side: commercial locksmith work such as lockouts, lock repairs, lock and cylinder replacement and break-in repairs, and talking through your doors so you know what to ask a system supplier. Our lock checklist for logistics warehouses is a useful companion when you're drawing up the door schedule.

As a mobile locksmith in Boksburg we come to your premises, 24/7, whether that's a warehouse in Jet Park, a factory in Anderbolt or an office elsewhere in our area. There's an R250 call-out, the technician quotes on site before any work starts, and nothing is done until you agree. Payment is by EFT, cash or card.

Need a locksmith to look at it?

If this hasn't solved the problem, our commercial locksmith service covers it. We're a mobile locksmith in Boksburg, so we come to your door.

Sources and further reading

• ABLOY UK: Master key systems — individual keys with a master and grand master over several groups; central coding, site survey and schematic; key control levels with registration cards, signed orders and sequential numbering
• Wikipedia: Master keying — change keys, master keys, multi-level tree; maison (common-entrance) keying; master keying generally reduces overall security; alternatives such as electronic access control
• ASSA ABLOY South Africa: Mzansi cylinder — keyed to differ, keyed alike and master key systems with up to 2,000 cylinders per master; grand master with up to ten sub-masters; patented sawn key
• ASSA ABLOY: Standards and patent protection for mechanical cylinders — patents let the maker restrict key copies to authorised partners and make blanks harder to produce; patents are time-limited
• Mul-T-Lock UK: MTL300 Break Secure 3XP Pro — "No card, no cut": keys copied only by authorised partners with a valid card