Access control fails at the door, not in the database

The reader is rarely the bottleneck

A modern RFID or QR reader validates in well under a second. If your hall doors are backing up, the read time is almost never the cause.

What causes it is geometry. A single-file speed gate passes roughly 20 to 25 people a minute when everyone has their badge ready and the reader is at a comfortable height. If 600 people are trying to enter a keynote in the four minutes before it starts, that is 150 a minute, and you need six lanes.

Nobody has six lanes. So the queue forms outside the hall, the session starts late, and somebody concludes the scanners are slow.

Where the seconds actually go

Watch a door for ten minutes and the pattern is consistent:

Badge retrieval. Delegates who have put their badge in a pocket or bag add three to eight seconds each. Lanyards worn visibly eliminate this, which is the entire reason for the lanyard.

Reader height and angle. A reader mounted for a standing adult at a comfortable arm position is read on the first attempt. One mounted too low or angled awkwardly generates second and third attempts, and each retry is two seconds plus the hesitation before it.

Two-way flow. A door used for both entry and exit halves in capacity and generates collisions. Separating them is free and is skipped constantly.

The person in front. Queue dynamics amplify everything above. One delegate fumbling for thirty seconds stalls everyone behind them, and the recovery takes longer than the delay itself.

Design for the session change, not the day

Total daily footfall through a door is meaningless. What matters is the worst four minutes, which is always the change between parallel sessions or the call into a keynote.

Estimate it directly: how many people need to be through this door, and in how long? Divide by 22 people per lane per minute. That is your lane count. If the answer is more lanes than you have doors, the fix is not technological — it is staggering the session change, opening a second entrance, or accepting a late start and building it into the run sheet.

When to check badges at all

Access control has a cost, so it should buy something specific:

• //Capacity compliance — the hall has a legal limit and you need to enforce it
• //Paid access tiers — workshops or a summit day that not everyone has bought
• //Security zones — VIP, backstage, government protocol requirements
• //Attendance data for CPD or sponsors — the scan is the record

If a door serves none of those, scanning it adds friction and gathers data nobody reads. Leave it open and put the reader where it earns its place.

The failure mode to plan for

Readers lose connectivity. This is not hypothetical; venue networks are the least reliable component in the room.

The requirement is that a reader keeps working offline, validating against a locally cached list and syncing when the network returns. If your access control stops admitting people because a switch rebooted, you do not have access control, you have a door with a computer next to it.

Test this deliberately: unplug the uplink during a rehearsal and confirm the door still works.