Active Fire Protection Systems

Active Protection

• Active fire protection involves various systems.
• Systems covered include rising mains, hose reels, fire suppression systems, fire alarm systems, and fire extinguishers.

Rising Mains

• Rising mains are vertical mains providing fire hydrants on each floor of a building, with landing valves as the 'fire hydrants'.
• Rising mains are required when a building is too tall for firefighters to reach from the outside
• Also when the floor area is too large to fight a fire from inside.
• Also if there's a basement

Number and Location

• Buildings with habitable height exceeding 10m require one or more rising mains
• Rising mains should cover all parts of the floors within a 38 m radius by hose, accounting for obstructions like walls.
• Rising mains and landing valves must be free of obstructions and located within the fire lift lobby or smoke-free lobby if available
• The alternative is an external corridor immediately outside the exit staircase
• When those options aren't available, inside the exit staircase or in a protected shaft near the exit staircase is admissable

Types of Risers

• Dry risers and wet risers are 2 types of risers.
• Dry risers are vertical pipes for firefighting, fitted with SCDF inlet connections
• Dry risers have landing valves on various floors.
• Dry risers normally remain dry but can be charged with water.
• An automatic valve at the top of the riser opens when water is pumped in
• This allows air to escape and closes when the pipe is full.
• Firefighters can connect hoses to landing valves to fight the fire.
• Dry risers are for buildings between 10 m to 60 m in height which have yellow landing valves

Wet Risers

• Wet risers are vertical pipes for firefighting, permanently charged with water from a pressurized supply.
• Wet risers have landing valves on each floor
• They are used for buildings exceeding 60 m in height and landing valves are painted red.
• A note indicates that except for Purpose Group II buildings, standby fire houses should be provided within 2m of the landing valve

Hose Reel

• Hose reels are first aid firefighting equipment consisting of tubing with a shut-off nozzle connected to a pressurized water supply.

Provisions

• Every storey of every building has at least 1 hose reel, regardless of building height.
• Fire hose reels should cover M&E plants/equipment on non-habitable roof levels.
• Exemptions apply to residential buildings under Purpose Group 1 and non-residential occupancy at the first storey of mixed commercial buildings.

Location

• Hose reels must be in prominent, accessible locations within 5 m of the exit door but not inside exit staircases.
• Additional hose reels are needed if parts of the floor space are beyond the 36 m coverage of the first hose reel.
• Hose reels within a room cannot cover areas outside of that same room.
• Hose reels at the top floors need pumps to achieve sufficient nozzle pressure for a 6 m water throw.
• Hose reels at the lower floors are fed by gravity

Fire Suppression Systems

• Fire suppression systems extinguish or control outbreaks, protecting people and property.
• They share general design principles and components, but addresses specific fire types
• Design and components include agent source, delivery system, discharge efficiency, and nozzle type/coverage.
• The firefighting agent can be water, wet chemical, foam, or inert gas, depending on the fire type.
• The delivery system is a network of pipes and pumps
• Discharge efficiency depends on pipe size, pump capacity, and nozzle design.
• Nozzle types and their spacing, discharge pattern, and coverage area must be optimal.

Types of Fire Suppression Systems

• Water-based and non-water based are two types
• Water based include water sprinklers, water mist systems, foam-water systems, and wet chemical systems

Water Based Systems

• Water sprinklers extinguish flames and cool areas.
• Drenchers use high-volume water spray for rapid fire suppression.
• Water mist systems use water mist to extinguish fires and suppress oxygen.
• Foam-water systems create fire-fighting foam blankets to smother flammable liquid fires.
• Wet chemical systems saponify hot cooking oils, extinguishing kitchen fires.

Sprinkler Head Types

• Upright sprinkler heads spray water upwards, used in structures with open ceilings.
• Pendant sprinkler heads descend and disperse water downwards, considered the most common type.
• Sidewall sprinkler heads protrude horizontally, used in small spaces with obstructions.
• Concealed sprinkler heads are flushed with the ceiling.
• Heat-sensitive plates detach at roughly 20 degrees lower, allowing the deflector to drop.

Sprinkler System Types

• There are four types of sprinkler systems, including wet pipe, dry pipe, pre-action, and deluge or drencher systems.
• Wet pipe systems have ready to discharge with sprinkler heads that automatically open at a specific temperature, compliant with SS CP 52.
• Wet pipes have water in the pipes at all times.
• Fire heats the head, which bursts and releases water.
• Flowing water triggers an alarm to warn everyone and a sensor activates a water pump.
• In dry pipe systems, pipes aren't filled with water, but air/nitrogen is
• Once the temperature breaks air/nitrogen is released creating a drop in pressure opening a dry pipe valve to fill and flow
• Dry pipes ideal for freezing environments such as cold rooms.
• Pre-action systems are dry until a detector activates water to pre-charge the sprinkler heads.
• Those systems are good for freezing environments
• Deluge or Drencher systems use open sprinkler heads or nozzles.
• Deluge systems discharge water simultaneously and are ideal for high hazard areas
• According to the Fire Code, sprinkler systems are needed at every storey above 24 m, or if compartmentation requirements are not met.
• Sprinklers should not exceed 18m.
• For atriums above 18m, water monitors, deluges, or extended-throw sprinkler systems are used.

Concealed Spaces

• These contain building services.
• Concealed spaces require smoke detectors or automatic sprinklers if they exceed 800mm in depth.

Classification of Sprinkler Systems

• Sprinkler systems classified by risk of occupancy: extra light, ordinary, or extra high hazard

Sprinkler System Components

• Sprinkler tanks are divided into two compartments of equal volume.
• Adequate water supply is required for 30 mins of pump operation.
• Jockey, duty, and standby pumps are placed in water rooms not lower than the main floor level.
• Jockey pumps maintain system pressure and stop automatically
• Duty pumps activate with a severe pressure drop and can only be switched off manually.
• Standby pumps activate when duty pumps fail.
• Standby pumps can only be switched off manually.
• Alarm valves maintain system pressure to test sprinklers on activation
• Flow switches activate alarms when water flows and are positioned in different zones.
• Sprinkler heads are heat-operated that activate when temperature rises will cause bulbs to break releasing water.
• Heads are color-coded for temperature ratings.
• Sprinkler breeching inlets allow firemen to supply water.

Inspection and Maintenance

• NFPA 25, SS CP 52, and NFPA 750 are used in inspection, test, and maintenance
• Obstructions require a 500mm clearance, and heads need inspection for corrosion, paint, leaks, or damage
• Standard heads need testing every 50 years, FR heads every 20 years, and solder heads every 5 years.
• Pipes and fittings need repair if damaged, hangers and seismic braces need repair as well
• Internal examination of blockages and strainers need to be flushed, and valves need to be checked
• Gauge conditions need to be checked weekly, and pressure settings need to be checked daily.

Automatic Fire Alarm System

• Detect and respond to fire by monitoring environmental changes associated with combustions
• Activated automatically or manually for fire detection, location identification, occupant alerts, personnel notification, and auxiliary equipment activation.

Fire Alarm Panels

• Are the processing unit of an automatic alarm system and process inputs from detectors and points to provide output to devices.
• Panels are addressable or non-addressable.

Automatic Fire Detectors

• Detect changes indicative of developing fire such as the presence of visibile smoke, illumination and temperature changing.
• Water Monitors use infra-red sensors and rotate to locate fire at under 20 mins of activation
• Heat detectors are installed at the highest point of the ceiling and are generally used for warehouses
• Detectors may be fixed-temperature, rate-of-rise, or combined
• Rate-of-rise-only detectors are not recommended.

Smoke Detectors

• Smoke detectors may be point-type or optical beam line-type.
• Principles used include light scattering, light obscuring, and ionization.

Home Fire Alarm Device

• New residential units must install HFAD since 2018.
• When flame occurs, household is alerted
• Technology includes status indicators, sounders, silence/reset, test buttons, and battery/electrical supply.
• In single-story homes, install a smoke detector in the living room, in a multistory home, install one per floor minimum

Flame Detectors

• They find the specific portion of the ight and are installed where damage risks are critical
• Flame detectors are part of light spectrum as designed, detects UV, IR or a combination of both.
• They feature flicker which requires filters to detect

Selection of Detectors

• The selected detector must depend on fuel type and location, different detectors will have different probabilities

Alarm Devices

• May be audible/ visual.

Portable Fire Extinguishers

• First line of defense for small fires.
• Fire Code mandates extinguishers for all except residential floors of Purpose Groups I & II.
• Extinguisher locations should be prioritised as near exit staircases, exits, common lobbies, rooms and internal paths.
• Cabinets for extinguishers should not be locked.

Agents

• Water is for Class A fires only
• Carbon Dioxide, suitable for most fires except open ones, puts out fire by removing oxygen
• Dry Powder is good with certain fires, and removes heat
• Foam, ideal for petrol fires
• Wet Chemical puts out fire by removing chemical
• A dry powder chemical has residue while Carbon Dioxide is non-toxic and will not stain.

Extinguisher Size and Class

• This is followed by a number such as 13A/70B
• Class A extinguishers are located so that no person travels > 15m (for each unit of “A”, the max floor covered is 15m2)
• Example: If room is 1500m2 will require 100A, and max reach of 15m can be achieved with 8x 13A units
• A fully charged exintguisher should not exceed 20kg

Operation

• To operate pierce a device and hose should not be under pressure
• Should be protected, and operation instructions must be followed

Maintenance

• Extinguishers should always come with a manufacturer's name, year, approved details
• Extinguishers are be clearly marked with the following: Manufacturer's name, number and date of applicable Singapore Standard
• The common method of operation for extinguishers stored pressure type
• Inspection frequency should be monthly if circumstances call, all extinguishers must be recharged after use
• At a minimum, follow the following conditions "Should frequency of fires increase, if severe hazards continue existing, or if characteristics are susceptible to leakage"

Explanation of different active fire protection systems. Systems covered include rising mains, hose reels, fire suppression systems, fire alarm systems, and fire extinguishers. Rising mains are vertical mains providing fire hydrants on each floor of a building, with landing valves acting as the 'fire hydrants'.