CFPS flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Fire tetrahedron

Four components needed for combustion: fuel, oxidizer, heat, and an uninhibited chemical chain reaction. Removing any one component extinguishes the fire.

Flash point

The lowest temperature at which a liquid gives off enough vapor to form an ignitable mixture with air near its surface, though burning does not necessarily continue once the igniter is removed.

Lower flammable limit

The minimum fuel vapor concentration in air, expressed as percent by volume, that will support combustion. Below the LFL the mixture is too lean to burn.

Heat release rate

The rate at which energy is released by a burning item, usually in kilowatts, equal to mass loss rate times heat of combustion. It governs fire growth and time to flashover.

BLEVE

Boiling liquid expanding vapor explosion: failure of a pressurized vessel holding liquid above its atmospheric boiling point, producing sudden vapor expansion, vessel fragments, and often a fireball.

Authority having jurisdiction

The organization, office, or individual responsible for approving equipment, an installation, or a procedure and for enforcing the adopted fire code within its legal boundaries.

Occupancy classification

Grouping of a building or space by its use, such as assembly, business, educational, industrial, storage, or residential, which sets the fire safety requirements in NFPA 101 and related codes.

NFPA 25

Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems. It specifies frequencies for gauges, valves, sprinklers, main drains, and flow tests.

Performance-based design

A design approach using engineering analysis, fire modeling, and documented acceptance criteria to demonstrate that stated fire safety goals and objectives are met, rather than following explicit prescriptive rules.

Smoke detector spacing

NFPA 72 allows up to 30 ft spacing and 900 sq ft per spot-type smoke detector on smooth ceilings, with detectors placed within 21 ft of sidewalls unless ceiling height changes the spacing.

Public mode notification

Audible alarms meant to alert occupants generally must sound at least 15 dBA above average ambient or 5 dBA above maximum ambient for 60 seconds, and at least 75 dBA at 10 ft.

Addressable alarm system

A system in which each initiating and notification device has a unique identifier, so the control panel annunciates the exact device in alarm or trouble instead of only a circuit zone.

Alarm verification

A panel feature that delays a smoke detector alarm to confirm it, reducing nuisance alarms. The panel resets and rechecks the detector, typically adding 60 to 180 seconds of delay.

Sprinkler K-factor

A discharge coefficient relating sprinkler flow to pressure: flow in gpm equals K times the square root of pressure in psi. A K of 5.6 is typical of a half-inch orifice.

ESFR sprinkler

Early Suppression Fast Response sprinkler designed to deliver high-density water and suppress a high-challenge storage fire without in-rack sprinklers, subject to limits on ceiling height and clearance.

Fire pump churn

The no-flow operating condition of a fire pump. Churn pressure must not exceed 140 percent of rated pressure so system components are not over-pressurized.

Sprinkler design density

The minimum water application rate in gpm per square foot over a specified remote area in a hydraulic calculation. The required density depends on the occupancy hazard classification.

Class K extinguisher

A wet chemical extinguisher intended for cooking media fires involving vegetable or animal oils and fats, required near commercial cooking appliances such as deep fryers and ranges.

Common path of travel

The single-direction route occupants must travel before two independent ways out are available. Codes cap its length by occupancy, and it counts within the overall travel distance limit.

Occupant load factor

The floor area in square feet or square meters assigned per person for a given use. Dividing floor area by the factor yields the occupant load used to size egress components.

RSET

Required safe egress time: the interval from ignition until occupants reach a place of safety, including detection, alarm, pre-movement, and travel time. It must be shorter than ASET.

Exit access

The portion of a means of egress leading from the occupied space to an exit, such as rooms, aisles, and corridors. Travel distance is measured along this path.

Dead-end corridor

A corridor segment with only one direction of escape travel. Its length is limited by code, commonly 20 ft in nonsprinklered and 50 ft in sprinklered business occupancies.

Hazen-Williams formula

An empirical pipe friction equation: head loss per foot equals 4.52 times Q to the 1.85 divided by C to the 1.85 times d to the 4.87, with Q in gpm and d in inches.

Residual pressure

The pressure remaining at a hydrant or gauge while water is flowing during a flow test. Comparing it with static pressure characterizes the available supply.

Needed fire flow

The estimated water rate in gpm required to control a fire in a building, derived from construction, occupancy, exposure, and communication factors and used to judge water supply adequacy.

Pitot pressure

Velocity pressure measured at a flowing hydrant or nozzle outlet with a pitot tube. Flow is computed from it as Q equals 29.83 times d squared times the square root of pressure in psi.

Class IB liquid

A flammable liquid with a closed-cup flash point below 73 degrees F and a boiling point at or above 100 degrees F, as classified by NFPA 30.

NFPA 704 diamond

A hazard identification marking with four colored quadrants rating health, flammability, and instability from 0 to 4, plus white for special hazards such as water reactivity or oxidizing ability.

Kst

The deflagration index: maximum rate of pressure rise normalized to vessel volume for a dust, expressed in bar-meters per second and used to assign St-1, St-2, or St-3 explosibility classes.

Risk

Risk is the product of an event's probability and the severity of its consequences. Risk management compares the evaluated risk against tolerable criteria and then selects controls.

Deflagration venting

Relief openings sized per NFPA 68 that let combustion gases and pressure escape an enclosure during a dust or gas deflagration, protecting the structure from catastrophic failure.