Fire Protection System

PURPOSE

• Protect building structure & contents from fire damage or total destruction

• Achieved by breaking at least one side of the Fire Tetrahedron (Heat, Fuel, Oxygen, Chemical Reaction)

METHODS OF HEAT TRANSFER

• Radiation – electromagnetic waves; can travel through space

• Conduction – heat moves through solid matter from molecule to molecule

• Convection – heat carried by moving fluids (liquids / gases)

BASIC FIRE-SAFETY FEATURES REQUIRED IN ALL BUILDINGS

• Portable fire extinguishers (water or inert-gas contents)

• Fire detection & alarm system

  • Initiating devices (smoke/heat detectors, pull stations)

  • Notifying devices (bells, strobes, horns)

• Standpipe system & fire-hose cabinets (incl. exterior Fire Department Connection)

• Automatic fire-suppression system (sprinklers, inert gas, etc.)

• Marked & unobstructed means of egress (illuminated exit signs, emergency lighting)

FIRE TETRAHEDRON

• Four elements: Heat, Fuel, Oxygen, Chemical Reaction

• Remove any element ⇒ fire is extinguished

CLASSES OF FIRE

• Class A – ordinary combustibles (wood, paper, cloth, rubber, plastic)

• Class B – flammable liquids & gases (gasoline, oil, solvents, propane, butane)

• Class C / E – energized electrical equipment (computers, motors). De-energize ⇒ becomes A or B

• Class D – combustible metals (Mg, Ti, Zr, Na, Li, K)

• Class K / F – cooking oils & fats (commercial kitchens)

PORTABLE FIRE EXTINGUISHERS

• NFPA 1 requires extinguishers for almost every occupancy except one- & two-family dwellings & manufactured homes

• Extinguisher rating converts to water equivalence:

  • 1A = 1.25\;\text{gal water}, 2A = 2.5\;\text{gal}, 4A = 5\;\text{gal}

  • 10B covers ≈ 10\;\text{ft}^2, 20B ≈ 20\;\text{ft}^2, etc.

Fire-Extinguishment Mechanisms

1. Cooling – absorb heat (water, foam-94 % water)

2. Smothering – dilute/displace oxygen (CO₂, closing doors, foam blanket, wet cloth)

3. Fuel removal – shut valves, relocate combustibles

4. Inhibition – break chemical chain reaction (dry chemical, halon/clean agents)

Main Extinguisher Types & Applications

• Water – Class A only; best cooling agent, shock hazard on C, spreads B

• Foam – Class A & B; costlier than water; safer than water on live electrical if overspray occurs

• Carbon Dioxide – Class B & C; little effect on A; very cold discharge

• Dry Chemical (ABC multipurpose) – interrupts chain reaction; most common; subclass: BC only may re-ignite if misused

• Wet Chemical – developed for high-efficiency fryers; Class K, some Class A

• Dry Powder – Class D metals only

• Clean Agent / Halogenated – interrupts reaction &/or removes heat; Class A, B, C; halocarbon alternatives to Halon (ozone concern)

• Water Mist – alternate to clean agents where contamination a concern; primarily Class A, safe on C

Color-Code (Tag / Body)

• Red = Water | Blue = Dry Powder | Cream = Foam | Black = CO₂ | Yellow = Wet Chemical | Green = Halon (legacy only)

Monthly User Inspection (3 Questions)

1. Located in correct place, visible & accessible?

2. Pressure gauge in the green zone?

3. Inspection tag present & current?

• Quick-check every 30\;\text{days}; professional maintenance yearly

• Obsolete units to remove: soda-acid, chemical foam, carbon tetrachloride, cartridge-water/loaded stream, soft-soldered copper/brass, etc.

Distribution Tables (select values)

• Class A low hazard: 2A, max travel 35\,m, 200\,m^2 per unit

• Class B low hazard: 5B, max travel 10\,m, 200\,m^2 per unit

• Class D: max travel 15\,m to extinguisher

Prohibited Acts

• Removing inspection tags, using wrong agent, selling substandard or non-matching extinguishers, false alarms, tampering w/ equipment, unsafe bonfires/incinerators, obstructed egress, etc.

“3 A’s” RULE FOR FIGHTING A FIRE

1. Activate alarm / call 911

2. Assist persons in immediate danger if safe

3. Attempt to extinguish only if:

   • fire small & contained, toxic smoke minimal, escape path available, instincts say OK

PASS Technique

• Pull pin – Aim at base – Squeeze lever – Sweep side-to-side

STANDPIPE SYSTEMS (NFPA 14)

• Vertical pipe network supplying hose outlets on each floor; water via FDC or internal supply

• Required high-rise (> 4 stories)

Classes

• Class I – 2{\tfrac12}'' (65 mm) outlets for Fire Dept (usually dry)

• Class II – 1{\tfrac12}'' (38 mm) outlets + occupant hose – often wet; many decommissioned

• Class III – combines I & II for FD + trained occupants; full-scale firefighting

Dry Standpipe Requirements

• Outlet each stair landing above first floor; no point > 40\,m travel

• Pipe slope \ge 20\% horizontal for drainage

• Size ≥ 102\,mm if highest outlet ≤ 23\,m above FDC; ≥ 153\,mm if > 23\,m

• Outlet height: 61–122\,cm above floor; signage “DRY STANDPIPE” w/ 25\,mm raised letters

Wet Standpipe Requirements

• Mandated for:

  • Assembly > 1000 occupants

  • Edu, health care, detention, business, mercantile, industrial, hotels/apartments ≥ 4 storeys

  • Hazardous storage & large mercantile (> 1860\,m^2 per floor)

• Coverage: all points within 6\,m of nozzle on 22\,m hose

• Pipe ∅ ≥ 64\,mm if riser ≥ 15\,m; else ≥ 51\,mm

• Outlet valve 38\,mm, located 91–182\,cm above floor

• Flow: ≥ 132\,L/min at ≥ 1.8\,kg/cm^2 (≈ 25.6\,psi) from any two simultaneous outlets for 30\,min

• Gravity / pressure tank capacity: \ge 265\,L/min for 30\,min

• Inspection: visual yearly; hydrostatic 200\,psi/2 h; air 40\,psi/24 h; full flow & hydro every 5 years

AUTOMATIC SPRINKLER SYSTEMS

• Piping + sprinkler heads + control valve + reliable water supply + alarm device

• Required in: assembly, educational, health care, hotels/dorms/apartments ≥ 4 storeys, mercantile ≥ 3 storeys or > 1115\,m^2 or basement > 232\,m^2, business ≥ 15\,m high, all high-hazard industrial

System Types

• Wet-Pipe – pipes always full of water; fastest response

• Dry-Pipe – pipes pressurized air/nitrogen; water admitted on activation; for freezing areas

• Deluge – open nozzles; valve opens → water to all heads; used in high hazard (power plants, aircraft hangars). Manual reset required

• Pre-Action – dry piping + electrically latched pre-action valve; needs confirmed detection before filling; protects museums, data centers

Piping Arrangements

• Tree – single-path feed; simplest, least efficient hydraulically

• Loop – cross-mains tied; multiple water paths, branch lines not interconnected

• Grid – parallel mains + interconnected branches; water to branch from both ends → most efficient

Key Components

• System riser (control valve, alarm devices)

• Feed / cross mains, branch lines

• Supervisory devices (flow switches, tamper switches)

• Flexible listed couplings (allow axial + angular movement)

• Quick-exhaust / automatic air vents on dry systems

Sprinkler Heads

• Quartz-bulb heat-sensitive element; bulb color ⇔ activation temp (e.g., red = 57°C / 135°F)

• Pendent – downward spray; through finished ceilings

• Upright – above exposed piping; protects against mechanical damage

• Recessed / Semi-recessed / Concealed – aesthetic or flush heads with escutcheons / cover plates

• Sidewall – quarter-sphere pattern along walls/corridors

• Special extended pendant, etc.

System Area Limit per Riser (any one floor)

• Light & Ordinary hazard: ≤ 52,000\;ft^2 (≈ 4831\;m^2)

Hazard Classifications

• Light hazard – low combustibles, low heat-release (churches, offices, residential, hospitals)

• Ordinary hazard Group 1 – moderate combustibles, stock ≤ 8\;ft (2.4 m): bakeries, laundries, electronic plants

• Ordinary hazard Group 2 – moderate–high combustibles, stock ≤ 12\;ft (3.7 m): distilleries, machine shops, mercantile

• Extra hazard Group 1 – very high combustibles, dust/lint, little flammable liquid: aircraft hangars, die-casting, rubber reclaiming

• Extra hazard Group 2 – high flammable/combustible liquids or heavy shielding: paint dipping, plastics processing, solvent cleaning

Exit Provisions for High-Hazard Occupancies

• Max travel distance to exit: ≤ 23\,m

• Exit width: ≥ 1 unit per 30 persons (stairs) or per 50 persons (doors / horizontal exits)

Sprinkler Head Spacing (NFPA 13 typical)

| Hazard | Coverage per head | Max head-to-head spacing |
| — | — | — |
| Light | 130–200\,ft^2 | 15\,ft |
| Ordinary (1 & 2) | 90–130\,ft^2 (calc) | 12\,ft |
| Extra (1 & 2) | 130\,ft^2 | ? per calc |
Other rules:

• Distance to walls ≤ ½ head-spacing, min wall clearance 4'' (≈100\,mm)

• Min head-to-head distance 6'' (≈150\,mm)

• Distance below ceiling: 1''–12'' (25–300 mm)

DEFINITIONS & MISC. TECHNICAL TERMS (selected)

• Automatic Fire Suppression System – integrated piping + agent source that activates via detectors

• Blasting Agent – fuel/oxidizer mixture for explosives

• Boiling Point – temp where liquid → vapor

• Combination Standpipe – standpipe constantly full of water for BFP & occupants

• Combustible Liquids – flash point ≥ 37.8°C; Class II (≥ 37.8°C < 60°C), IIIA, IIIB

• Corrosive Liquid – causes fire w/ organics or certain chems

• Cryogenic – produces rapid cooling (He, H₂, Ne)

• Damper – device inside ducts closes to restrict smoke/fire

• Dust – ≤ 4\,mm particles capable of explosive suspension

• Electrical Arc – luminous bridge between conductors

• Explosive Magazine – storage for explosives/ammunition

• Fire Trap – building lacking exits, easy ignition

• Fogging – aerosolizing insecticide into fine droplets

• Incipient Stage Fire – controllable with extinguishers / Class II hose; no SCBA required

• Multipurpose Dry Chemical – ABC rated agent

• Plenum – air chamber in distribution system

• Pyrophoric – self-ignites on air contact (FeS)

• Standpipe System – vertical piping with hose outlets on each floor

• Vertical Shaft – enclosed floor-to-floor space (elevator, duct)

• Plastics Classification

  • Group A: very high heat release/burn rate (ABS, PU foam, PS, etc.)

  • Group B: lower than A but > ordinary (nylon, PVC 5-15 %, silicones)

  • Group C: similar to ordinary combustibles

INSPECTION, TESTING & MAINTENANCE SUMMARY

• Extinguishers: visual monthly, prof. yearly, 6-year tear-down / hydrostatic as per NFPA 10

• Standpipes: yearly visual; hydrostatic 200\,psi every 5 yrs; air leak 40\,psi 24 h; NPT threads or per local FD; signage installed

• Sprinklers: quarterly/annual inspections, 5-yr internal pipe obstruction check, flow tests, spare head cabinet (minimum 6 heads each temp type)

ETHICAL & LEGAL NOTES

• Illegal to transmit false alarms or tamper with equipment

• Bonfires ≥ 15\,m from structures; incinerators ≥ 5\,m

• Combustible waste to be stored in metal cans with tight covers

• Buildings must ensure unobstructed illuminated egress & operational alarms

PRACTICAL CONNECTIONS & EXAM TIPS

• Remember PASS & 3 A’s for situational questions

• Standpipe class clues: I = FD, II = Occupant, III = Both

• Dry vs Wet standpipe relation to story height and climate (freeze potential)

• Fire load & hazard group drive sprinkler density, spacing, & occupancy designations

• Plastic group impacts sprinkler design & occupancy fire load calculations