CFPS cheat sheet

Fire tetrahedron: fuel, oxidizer, heat, and an uninhibited chemical chain reaction. Removing any one of the four extinguishes combustion.

Flash point is the lowest temperature at which a liquid emits enough vapor to ignite momentarily; the fire point is the slightly higher temperature at which vapor burning continues.

Flammable limits bracket the combustible concentration range in air: below the LFL the mixture is too lean, above the UFL it is too rich.

Radiant heat flux from a blackbody follows q'' = epsilon * sigma * T^4, with sigma = 5.67e-8 W/(m^2*K^4); piloted ignition of common cellulosic fuels occurs near 10-20 kW/m^2.

Heat release rate Q = mass loss rate times heat of combustion; a t-squared growth fire is characterized by the time to reach 1055 kW (1 Btu/s scale reference: 1 MW).

Thermal inertia (k * rho * c) governs ignition resistance: low thermal inertia materials heat quickly at the surface and ignite sooner.

Conduction, convection, and radiation are the three heat transfer modes; radiation dominates once flames are large relative to the receptor distance.

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

Fire classes: A ordinary combustibles, B flammable liquids and gases, C energized electrical, D combustible metals, K commercial cooking media.

NFPA 1 is the Fire Code, NFPA 101 is the Life Safety Code, and NFPA 5000 is the Building Construction and Safety Code; all are consensus documents adopted by the authority having jurisdiction.

NFPA 220 defines Construction Types I through V, with Type I (noncombustible, highest fire resistance) through Type V (combustible, lowest fire resistance).

Maintenance standards: NFPA 25 for water-based systems, NFPA 72 for detection and alarm, NFPA 10 for portable extinguishers, NFPA 11/16/17 for foam and gaseous agents.

Hot work is regulated by NFPA 51B, which requires a written permit, a fire watch, and a 60-minute post-work monitoring period.

Occupancy classification (assembly, business, educational, factory, high hazard, institutional, mercantile, residential, storage, utility) drives egress, sprinkler, and alarm requirements.

The AHJ approves equipment and installations, may grant equivalencies, and enforces the adopted code; retroactivity applies when a specific code section says so.

Prescriptive design applies explicit code rules; performance-based design uses engineering analysis, fire modeling, and documented acceptance criteria to meet stated goals and objectives.

The enforcement sequence is plan review, permit issuance, inspection of construction and systems, and certificate of occupancy; periodic inspections sustain compliance afterward.

NFPA 72 governs the design, installation, testing, and maintenance of fire detection, alarm, and emergency communication systems.

Smooth-ceiling spacing limits: spot-type smoke detectors at 30 ft spacing and 900 sq ft per detector; heat detectors at 50 ft spacing and 2500 sq ft per detector, with detectors within 21 ft of sidewalls.

Detector selection: ionization responds best to flaming fires and small particles; photoelectric responds best to smoldering fires and visible smoke; heat detectors are fixed-temperature, rate-of-rise, or combination.

Public mode audible notification requires 15 dBA above average ambient (or 5 dBA above maximum ambient sustained 60 s) and at least 75 dBA at 10 ft from the device.

Private mode audible notification requires 10 dBA above ambient, with a minimum sound level set by code for the space; visible appliances are rated in candela per NFPA 72 spacing tables.

Addressable systems assign a unique identifier to each device so the panel annunciates the specific device in alarm or trouble; conventional systems annunciate by circuit or zone.

Initiating device circuits and notification appliance circuits are Class A (redundant path, survives a single open) or Class B (single path, trouble on open).

Alarm verification delays a smoke detector alarm for confirmation (typically 60-180 s) to reduce nuisance alarms; it must not be used where immediate response is required.

Voice evacuation systems must meet intelligibility criteria, commonly expressed as a Speech Transmission Index or Common Intelligibility Scale score.

NFPA 13 covers commercial sprinkler design, NFPA 13R covers residential occupancies up to four stories, and NFPA 13D covers one- and two-family dwellings.

Sprinkler discharge follows Q = K * sqrt(P), where Q is gpm, K is the discharge coefficient, and P is pressure in psi; a K-5.6 sprinkler is typical of a 1/2-inch orifice.

Density-area design: required flow equals the design density (gpm/sq ft) times the remote area (sq ft), plus any inside/outside hose allowance.

Sprinkler temperature ratings: 135-170 F ordinary, 175-225 F intermediate, 250-300 F high; bulb or link color identifies the rating.

NFPA 14 standpipe classes: Class I for fire department 2.5-inch connections, Class II for 1.5-inch occupant hose, Class III for both.

NFPA 20 fire pump curve points: churn (no flow) not exceeding 140 percent of rated pressure, 100 percent of rated flow at rated pressure, and 150 percent of rated flow at not less than 65 percent of rated pressure.

NFPA 10 extinguisher travel distances: maximum 75 ft for Class A, 50 ft for Class B, and 30 ft for Class K in commercial cooking areas.

Clean agent total flooding systems are designed to a concentration above the flame extinguishing value but at or below the NOAEL where occupied, with a typical 10-minute holding time and pre-discharge egress.

Foam expansion ratios: low expansion below 20:1, medium expansion 20:1 to 200:1, high expansion above 200:1.

A means of egress has three parts: exit access (path to the exit), the exit itself (protected stair, enclosed corridor, exterior door), and exit discharge (path to the public way).

Egress capacity width per occupant is 0.2 in (5 mm) for level components and 0.3 in (7.6 mm) for stairs and ramps in NFPA 101.

Occupant load factors: business 100 sq ft per person, assembly unconcentrated (tables and chairs) 15 sq ft per person, standing space 5 sq ft per person.

Travel distance limits vary by occupancy; business occupancies allow 200 ft unsprinklered and 250 ft sprinklered.

Dead-end corridors are limited to 20 ft in nonsprinklered and 50 ft in sprinklered business occupancies; common path of travel is separately limited and counts within travel distance.

Egress doors require at least 28 in clear width; doors serving an occupant load of 50 or more must swing in the direction of egress travel.

Exit signs and emergency lighting must function for at least 90 minutes on the emergency power source, with initial illumination averaging at least 1 footcandle along the path.

Handrails are typically 34 in above the tread nosing; guards are at least 42 in high where a drop exceeds 30 in.

RSET (required safe egress time) must be less than ASET (available safe egress time); RSET includes detection, alarm, pre-movement, and travel time.

Static pressure conversion: 1 psi equals 2.31 ft of water head, or 0.433 psi per foot of elevation.

Nozzle or orifice flow: Q = 29.83 * d^2 * sqrt(P), with Q in gpm, d in inches, and P in psi; the discharge coefficient K equals Q / sqrt(P).

Hazen-Williams friction loss per foot of pipe: 4.52 * Q^1.85 / (C^1.85 * d^4.87), with Q in gpm, d in inches, and C the roughness coefficient (about 120 for cement-lined ductile iron, 140-150 for plastic).

Bernoulli energy balance: P1/w + Z1 + V1^2/2g = P2/w + Z2 + V2^2/2g, adjusted for friction and fitting losses.

A hydrant flow test records static pressure, residual pressure, and pitot pressure at a known flow; the results establish the water supply curve for hydraulic analysis.

Needed fire flow is estimated from construction, occupancy, exposure, and communication factors (NFF = Ci * Oi * (1 + X + P)) and compared with available flow at 20 psi residual.

Water supplies are classified as public hydrant systems, gravity tanks, suction sources, or pressure tanks; adequacy is judged at the required residual pressure for the demand.

Excessive velocity causes noise and erosion; sprinkler piping design commonly targets velocities of roughly 15-20 ft/s or less.

Backflow prevention assemblies protect the public supply from cross-connection with private fire protection systems and must be tested and maintained.

NFPA 30 liquid classes: Class I has a flash point below 100 F and is split into IA (below 73 F, boiling point below 100 F), IB (below 73 F, boiling point at or above 100 F), and IC (73-100 F); Class II is 100-140 F; Class IIIA is 140-200 F and IIIB at or above 200 F.

NFPA 704 markings use four quadrants rated 0-4: blue health, red flammability, yellow instability, and white special hazards (such as water reactivity or oxidizer).

A safety data sheet under the GHS format has 16 sections, with fire-fighting measures in Section 5 and stability/reactivity in Section 10.

Storage of Class I and II liquids in a listed cabinet is limited to 60 gallons per cabinet (120 gallons for Class III) with no more than three cabinets per fire area.

DOT hazard classes run from Class 1 explosives through Class 9 miscellaneous; the Emergency Response Guidebook provides initial isolation distances and protective actions by UN number.

Dust hazard metrics include Kst (deflagration index, bar-m/sec, St-1/2/3 classes), Pmax (maximum explosion pressure), and MIE (minimum ignition energy); NFPA 68 sizes deflagration venting and NFPA 69 covers explosion prevention and isolation.

Risk is evaluated as probability of occurrence times consequence severity; controls are ranked so that elimination, substitution, and engineering controls precede administrative controls and PPE.

A BLEVE occurs when a pressurized tank containing liquid above its atmospheric boiling point fails, releasing a vapor expansion, vessel fragments, and potentially a fireball.

Hot work near flammable liquids or dusts requires a permit, combustible-free area, gas monitoring where appropriate, and a post-work fire watch.