> ## Content Index > Fetch the complete content index at: https://beathantechnologies.com/blog/llms.txt > Use this file to discover other available public pages before exploring further. # What is an occurrence book (OB) in security? - URL: https://beathantechnologies.com/blog/what-is-an-occurrence-book/ - Published: 2026-10-13T08:00:00.000Z - Updated: 2026-10-13T08:00:00.000Z - Description: The OB is the first thing a client or the police ask for after an incident. What it is for, what an OB number means, and why Sentry's digital OB has no incident types. - Author: Liam van Huyssteen - Tags: Security operations, Sentry, #kw: occurrence book An occurrence book in security is the running record kept at a guard post: every incident, every routine check and every visitor problem, written down in time order as it happens. On many South African sites it is still a numbered paper book in the guardhouse, and it is the first thing a client, an insurer or the police ask for when something goes wrong. Security officers call it the OB. If it happened on your shift, it goes in the book. ## What is an occurrence book in security used for? The OB does two jobs. The first is recording incidents. A broken fence, a vehicle that would not stop at the boom, an argument at the gate, a power failure that took the cameras down. Each entry is the officer's account, made close to the time, before memory and other people's versions get involved. The second is proving the post was attended. On a quiet night there is nothing to report, which is exactly why routine entries matter. A book with nothing in it between 22:00 and 06:00 reads as a guard who was asleep or absent, whatever actually happened. Six weeks later, both come down to whether somebody who was not there can read the book and trust it. ## What is an OB number? An OB number is the reference for one entry, so it can be quoted on the phone, in an email or in a report without anyone describing the incident again. In a paper book it is usually the page and line, or a running number the officer writes in. You will also hear the term at a police station, where an OB number refers to an entry in the station's own occurrence book. That is not the same as a CAS number, which the police issue when a criminal case is opened. In Sentry the reference is a date and a daily count, for example `2026-09-01-018`: the eighteenth entry logged on 1 September 2026\. The count starts again every day, so a supervisor reading the number knows the date and roughly how busy the day was before opening the entry. ## What is a situation report in an occurrence book? A situation report is the entry for "everything is in order". It is the routine check a guard logs on a quiet shift, and it is the entry that proves the post was manned. Sentry treats it as the first of six severity levels: Situation report, then Low, Medium, High, Critical and Emergency. The guard chooses the severity when logging, and it cannot be changed once the entry is submitted. If the company switches on shift reminders, the handset prompts the guard at intervals to log an entry, with or without signal. ## Paper OB or digital occurrence book? A paper book fails in predictable ways. It can be filled in at 05:30 for the whole night. A page can go missing. The handwriting can be unreadable. It holds no photographs. And there is one copy, in a drawer at a site forty kilometres from the office, when the client phones about Tuesday. A [digital occurrence book](https://beathantechnologies.com/sentry/occurrence-book) cannot make a guard write a better entry, but it can make the entry impossible to backdate or quietly change. In Sentry: - The guard identifies themselves the same way they do to [clock in at the post](https://beathantechnologies.com/sentry/roll-call), so every entry carries the name of the person who made it. - The guard's own position is recorded automatically and cannot be edited. Where the incident happened is recorded separately, so a guard can report a fence breach they can see from the guardhouse. - Photographs and witnesses go on the entry. - The control room moves each entry through a status: Unresolved, Under investigation, Escalated to commander, Handed over to police, Resolved. - Later information goes in with Add info, a note or more photographs carrying their own time. The original entry stays exactly as it was logged. That last point is what makes the record worth sending to a client. An entry anyone can rewrite afterwards is not evidence. ## Why does Sentry's occurrence book have no incident types? Other OB software our clients had used asked the guard to pick an incident type from a list before they could write anything. Their complaint was that logging took too long: at 02:00, with something happening at the gate, the guard was scrolling through categories instead of writing down what they saw. So Sentry asks for a severity and a description. The guard picks one of six levels and writes the rest in their own words. We would rather have the entry made at 02:05 in plain language than a neatly categorised one written up at the end of the shift. ## Where to go from here An occurrence book is one half of the record a client will ask for. The other half is attendance: who was on site, where, and when. We covered that in [what a defensible attendance record contains](https://beathantechnologies.com/blog/proving-guard-attendance/). If you are still running a paper OB and want to see the digital version against your own sites, [talk to us.](https://beathantechnologies.com/contact)