Detection and response is a chain of four links, finding the fire, sounding the alarm, getting people out and acting on the fire, and the chain is only as fast as its slowest link. A night patrol every 30-60 minutes leaves a fire undetected for 15-30 minutes on average and for 30-60 minutes at worst, and two patrols offset by half an interval cut the average and the worst case in half.
Part of Fire Prevention in Settlements
Detection and response is the part of fire planning that finds a fire early, tells everyone, and starts the right action in the right order.
The Fire Guide Puts Detection First Because Most Fatal Fires Start At Night
The fire guide says most fatal fires start at night when people are sleeping, and sets up a rotating night watch that walks the settlement every 30-60 minutes, checks that cooking and heating fires are contained, listens and smells for fire and sounds the alarm at once. It asks for an alarm heard in every building, distinct from the security alert, and a response sequence everyone knows: sound the alarm, alert the occupants, assess, fight if small, contain if large, and count everyone at the assembly point.
Those are four links. Finding is the watch. Telling is the alarm (Night Watch & Alarm Systems). Getting out is the evacuation (Evacuation Routes & Assembly). Acting is the protocol and the water (Response Protocols & Training).
Worked Example: How Long A Fire Burns Before Anyone Sees It
Inputs: a patrol passes any given building every T minutes; a fire starts at a random moment between passes.
- Worst case: it starts just after the patrol has passed, and burns for T minutes: 30 to 60 minutes.
- Average: half the interval, T ÷ 2 = 15 to 30 minutes.
- Two patrollers walking the same loop half an interval apart pass every building every T ÷ 2: 15-30 minutes worst case and 7.5-15 minutes on average.
- A patrol on a loop of length L at walking speed v takes L ÷ v. A loop of 940 m (the circumference of a settlement of 150 m radius, an illustrative size) at 1 m/s with stops takes about 940 ÷ 1 = 940 s, about 16 minutes. A patrol with a 30-minute interval is walking for about half the time, and one with a 60-minute interval a quarter.
The watch is therefore a way of shortening the delay, not of eliminating it, and every minute of delay is a minute in which a fire that a bucket could stop grows past what a bucket can stop. A sleeping household also cannot be relied on to notice: as I recall, sleepers do not reliably wake to the smell of smoke, so a household’s own detection is weak and the watch and the alarm carry the load.
What You Need
- A night watch and a rota (Watch and Patrol Scheduling)
- An alarm audible in every building and different from the security alert
- Dogs and animals as a second sense (Animal Sentinels)
- Rehearsed responses and a roster for each cluster
- Water and buckets at the clusters
Method: Build The Chain
Step 1: Set the patrol interval from the table above and the staff you have; shorten it in dry, windy weather.
Step 2: Give the patrol a route through the fire-using workshops and fuel stores first, since they are the likeliest starting points (Fire Safety & Suppression).
Step 3: Make the alarm the same for everyone and drill it.
Step 4: Time each link in drills and fix the slowest.
Step 5: Review every real event and every drill in writing.
Common Mistakes
- A fast alarm and a slow watch. The alarm cannot sound for a fire nobody has seen.
- One signal for everything. People then do not know whether to run or hide.
- Stopping the watch in good weather. Cooking fires and stoves burn in all weather.
- Fighting before alerting. The fire guide’s first step is to sound the alarm, even before fighting.
Safety
The first act is to warn, not to fight
A person who finds a fire and tries to put it out alone, without sounding the alarm, risks being trapped while the household sleeps. Shout and sound the alarm first, get the occupants out, and only then judge whether the fire is small enough to fight with the exit behind you.
What’s Next
- Learn next: Night Watch & Alarm Systems — the first two links in detail
- Combine with: Emergency Assembly Areas — counting people after the alarm