SCO Fire cheat sheet

Fire tetrahedron: fuel, oxidizer, heat, and an uninhibited chemical chain reaction; removing any one leg extinguishes combustion.

Flammable limits define the concentration range in air that will burn; below the LFL the mixture is too lean, above the UFL too rich.

Flash point is the lowest temperature at which a liquid gives off enough vapor to ignite momentarily; fire point is the higher temperature sustaining continuous burning.

Class A: ordinary combustibles (wood, paper, cloth); Class B: flammable/combustible liquids and gases; Class C: energized electrical; Class D: combustible metals; Class K: cooking oils and fats.

Heat release rate (kW) drives fire growth; time-to-flashover shortens as HRR and compartment ventilation increase.

Four stages of compartment fire: incipient, growth, fully developed, and decay; flashover marks transition from growth to fully developed.

Autoignition temperature is the temperature at which a material ignites without an external pilot; it is always above the flash point for liquids.

Smoldering combustion produces glowing embers and dense smoke with little flame; flaming combustion produces visible flame and higher radiant heat.

Ionization detectors respond faster to flaming fires with small particles; photoelectric detectors respond faster to smoldering fires with larger particles.

Spot-type heat detectors are rated by fixed temperature or rate-of-rise; combination units respond to both criteria.

A conventional (zone) system annunciates by circuit or zone; an addressable system identifies each device individually.

Notification appliance circuits (NACs) power horns, strobes, and speakers; NFPA 72 sets audible and visible signaling criteria for occupancies.

Supervisory signals indicate off-normal conditions (valve closed, power loss) that impair protection but are not alarms.

Trouble signals indicate system faults (open circuit, ground fault, low battery); they must annunciate distinctly from alarm and supervisory signals.

Smoke detector spacing follows the manufacturer's listed coverage; NFPA 72 provides default spacing and smooth-ceiling rules when listings are absent.

Manual pull stations must be located along the normal path of egress and within the travel distance specified by the applicable code.

Water is the primary agent for Class A fires; it cools and absorbs heat, and is unsuitable for energized electrical or combustible metal fires.

Wet chemical (potassium-based) agents saponify cooking oils and are the standard for Class K kitchen hood suppression.

Clean agents (FM-200, Novec 1230, inert gases) extinguish by heat absorption and oxygen displacement with minimal residue; they require room integrity and hold time.

CO2 displaces oxygen and cools; it is hazardous in occupied spaces due to asphyxiation risk and is not used where people remain.

Dry chemical (ABC) extinguishers interrupt the chemical chain reaction; BC extinguishers use sodium or potassium bicarbonate.

Wet-pipe sprinklers have water under pressure in the piping and discharge immediately on sprinkler activation; dry-pipe systems hold air and are used in freezing environments.

Sprinkler discharge density (gpm/ft²) and design area are the core hydraulic design parameters; each sprinkler covers a listed protection area.

A standpipe system supplies water to hose connections in a building; classes I, II, and III correspond to different hose and occupant use.

Means of egress components: exit access, exit, and exit discharge; each must be continuous and unobstructed.

Occupant load is calculated from floor area divided by the occupant load factor for the use; egress capacity derives from that load.

Egress width is measured in inches per occupant, with minimum clear widths for corridors and doors set by code.

Travel distance to an exit is limited by occupancy and sprinkler protection; common-path and dead-end limits also apply.

Two remote exits are required where occupant load exceeds thresholds or where a single exit would be blocked by a single fire.

Exit signs must be illuminated and visible; emergency lighting must maintain minimum illumination along egress paths for the required duration.

Fire resistance ratings of separations (walls, floors, doors) protect egress and are expressed in hours.

High-rise and assembly occupancies add requirements such as voice evacuation, area of refuge, and occupant notification.

NFPA 1 (Fire Code) and NFPA 101 (Life Safety Code) are model codes; the locally adopted edition governs enforcement.

NFPA 13 covers sprinkler installation; NFPA 72 covers detection and alarm; NFPA 10 covers portable extinguishers.

Hot work permits are required for welding, cutting, and grinding; a fire watch is maintained during and after hot work.

Housekeeping controls ignition sources and fuel load: storage clearance from heaters, no accumulation of combustibles in egress paths.

Fire prevention plans address ignition control, fuel control, and employee training; hot work, smoking, and electrical safety are common program elements.

Inspection, testing, and maintenance (ITM) intervals are set by the applicable standard: monthly, quarterly, semiannual, or annual depending on the system.

Deficiencies found during inspection must be documented and corrected; impaired protection requires notification and interim measures.

Occupancy classification drives allowable construction type, height, area, and required fire protection features.

Incident Command System (ICS) uses a common organizational structure: command, operations, planning, logistics, and finance/administration.

The incident commander establishes command and maintains unity of command; command transfers require a briefing and formal transfer.

Size-up evaluates life safety, incident stabilization, and property conservation, in that priority order.

The PASS technique for extinguisher use: Pull the pin, Aim at the base, Squeeze the handle, Sweep side to side.

RACE sequence: Rescue, Alarm, Confine, Extinguish or Evacuate; alarm activation and evacuation precede firefighting by untrained occupants.

Inspection findings are documented with location, deficiency, code reference, and corrective action; reinspection verifies correction.

Pre-incident plans identify access, hydrants, utilities, hazards, and occupancy details before an incident occurs.

Post-incident critique and reporting support improvement; near-miss and injury data inform prevention programs.