fire
Let an agent treat fire as a process with a fuel, a growth curve and a set of interventions, so it can act on prevention, detection and response rather than only on the event.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent treat fire as a process with a fuel, a growth curve and a set of interventions, so it can act on prevention, detection and response rather than only on the event.
The rapid oxidation of a fuel that releases heat and light, sustained as long as fuel, oxygen and heat remain together.
What it is for: In controlled form: heat, cooking, power, disposal, land management. Uncontrolled, it is the hazard everything about buildings is designed around.
It can be start it, deliberately or by accident; contain it, which is what compartments and doors are for; extinguish it, by removing fuel, oxygen or heat - and the right one depends on the fuel; detect it, which is the difference between a small fire and a total loss; escape from it, which is what the whole means of escape apparatus exists for.
Distinguishing features
A process rather than a thing, so it has a start, a growth curve and an end rather than properties
Classified by fuel, and the classification decides which extinguishing agent is safe
The fire, the smoke and the heat cause different harms and travel at different speeds
Controlled and uncontrolled fire are the same process under different management
What it looks like
Flame, smoke and glow, in colours and forms that indicate the fuel and the stage; smoke is usually seen first and is what kills.
Physical character
flame temperature: 600-1200 C - depends on fuel and oxygen supply
time to flashover: 3-10 minutes - in a furnished room, and much faster than most people expect
tenable visibility: 5-10 m - the threshold below which escape becomes unlikely
fire resistance of construction: 30-120 minutes - what a compartment is rated to hold, tested in a furnace rather than in a fire
How it is recognised
Smoke colour and behaviour indicate fuel and stage better than flame does
Flame colour indicates temperature and fuel roughly and unreliably
Absence of visible flame does not mean absence of fire: smouldering can persist for hours inside a structure
Heat, not flame, is what a thermal detector sees and what makes a door unsafe to open
Related models
consumes - the fuel decides everything about how it behaves and how it is fought
produces - smoke causes most fire deaths and moves far ahead of flame
is contained by - the fundamental fire safety strategy in buildings
is detected by - detection time dominates outcomes
regulated by - prevention, means of escape and equipment are all mandated
In practice
Families and kinds
by fuel class: solids, flammable liquids, gases, metals, cooking oils, electrical
by setting: structure, vehicle, wildland, industrial
by stage: ignition, growth, flashover, fully developed, decay
Identifiers
fire class A, B, C, D, F or K by region names the fuel class and so the correct agent
incident reference service-specific identifies a particular fire as an event
Standards and regulation
Building fire safety codes, which set compartmentation, escape and detection requirements
Extinguisher classification and siting standards, which match agent to fuel class
Fire risk assessment duties, which oblige a responsible person to assess and act
Wildland fire management rules, where the same process is managed rather than prevented
Failure modes and hazards
Smoke inhalation, which causes most deaths and happens before flame arrives
Flashover, after which a room is not survivable and escape is over
Wrong extinguishing agent, which can spread a fire rather than stop it
Blocked or locked escape routes, the failure that turns a survivable fire into a fatal one
Re-ignition from smouldering material after apparent extinction
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.fire-substance
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Fuel and behaviour What is burning and what that means.
Fuel decides growth rate, temperature, smoke and the correct response, so it is the first thing a model must pin down.
Fuel and class
What is burning and which class it falls in.
Fuel classification
The fuel present and the class that follows.
- What fuel is involved, and which fire class does it fall in? definition
- Which extinguishing agents are safe for it, and which would make it worse? action
Growth and stage
How fast it develops and where it is now.
Stage and trajectory
The current stage and how quickly the next arrives.
- What stage has this fire reached, and how long until the next? measurement
- After which point does intervention stop being possible? boundary
Detection and warning How it is noticed and who is told.
The interval between ignition and warning determines the outcome more than any other single factor.
Detection
What detects it and how quickly.
Detection means and delay
The systems present and the time they take.
- What detection is in place here, and what delay does it introduce? measurement
- What was the last test of that system, and what did it show? provenance
Alarm and notification
Who is told, how, and what they do.
Warning and response
The people warned and the action expected of them.
- Who is warned when this fire is detected, and by what means? definition
- What action is expected of each of them, and who verifies it happened? action
Containment and escape Holding it back and getting people out.
Buildings do not stop fires; they buy time, and the model has to say how much and for whom.
Containment
Compartments, doors and rated construction.
Compartmentation in place
What is meant to hold, for how long.
- What compartmentation applies here, rated for how long? definition
- What breaches it in practice - propped doors, service penetrations - and how is that checked? boundary
Means of escape
Routes, capacity and time available.
Escape provision
Whether people can get out in the time the building buys.
- What escape routes serve this place, and what is the travel distance? measurement
- Who cannot use them unaided, and what provision is made for them? action
Prevention and duty Stopping it starting and who is answerable.
Fire safety is a continuing duty on a named person, and almost every serious fire traces back to a lapse in that duty rather than to bad luck.
Ignition sources and controls
What could start it and what prevents that.
Sources and controls
The plausible sources here and the controls in place.
- What ignition sources are present, and what controls each? definition
- Which control has failed or is missing, and what follows from that? action
Responsible person and assessment
Who must assess and act.
Duty holder and assessment
Who is answerable and when they last assessed.
- Who holds the fire safety duty here, and when was the assessment last reviewed? provenance
- What must be done when the assessment is out of date or its actions are outstanding? action
What the second pass must settle
- Should the registry model fire the process, the incident and the risk separately, since duties attach to the risk and records to the incident?
- How should fuel class be represented when a real fire involves several classes at once?
- What is the right way to represent time in this model, given that every important fact about a fire is a function of minutes elapsed?