Water-Based Fire Suppression Systems Flashcards
Name basic types of automatic sprinkler systems. (505-507)
Wet-pipe sprinkler system
Dry-pipe sprinkler system
Deluge sprinkler system
Preaction sprinkler system
Antifreeze sprinkler system
Circulation closed-loop sprinkler system
Combined dry pipe & preaction sprinkler system
Multicycle sprinkler system
List the major components included in automatic sprinkler systems.(508)
Water supplies
Waterflow Control Valves
- outside stem & yoke (OS&Y)
- post indicator valve (PIV)
- wall post indicator valve (WPIV)
- post indicator valve assembly (PIVA)
Operating Valves
- alarm-test valves
- check valves
- drain valves
- trim valves
- drip check or drip ball valves
Water Distribution Pipes
Sprinklers
Detection and Activation Devices
What are some of the characteristics of residential sprinkler systems? (515, 518-519)
Address life safety by working to prevent flashover in the room of origin and enabling occupants to evacuate. The cost is lower than an NFPA 13 system and some of the components have been scaled back.
- Some systems are fully integrated into the domestic plumbing system.
- Sprinkler heads are designed for fast response.
- Distribution patterns discharge water to break the thermal layering and prevent flashover conditions.
- Lower water supply requirements
- 18gpm for single sprinkler, 13gpm ea for two
- 144sf max per sprinkler, 12x12 spacing with max 6’ from wall (some sprinklers may allow for greater spacing)
How does a water-spray fixed system operate? (520-521)
NFPA 15 and NFPA 25 (testing inspection maintenance). Discharges water over area or surface through an arrangement of pipes and nozzles. Activated by automatic heat detection system or manual activation system.
Components:
- reliable water supply
- piping
- automatic or manual detection & activation devices
- waterflow control valve
- water-spray nozzles
Applies water droplets of a predetermined pattern, particle size, velocity, and density through specially designed nozzles.
Hazard categories:
- Flammable gaseous and liquid materials
- Electrical Equipment
- Ordinary Class A combustibles
- Certain hazardous solids (propellants, pyrotechnics)
- Exposure protection (separate hazards, means of egress)
Explain how a water-mist systems works. (521-523)
NFPA 750 and NFPA 25 (test/insp/maint). Similar to water-spray fixed system except it discharges a fine mist of water.
- Absorbs larger quantities of heat that water-spray or automatic.
- Raises humidity of room enough to halt combustion.
- Displaces oxygen and blocks radiant heat production.
- Less water damage
- higher pressures (low 175 psi, intermediate 175-500 psi, high 500 psi) created by compressed air, nitrogen, or high-pressure water pumps
- Air pressure may be supplied in water tube itself or second air tube to each nozzle.
- Small diameter, pressure rated copper or stainless steel tubing
- similar to deluge, all nozzles in room or zone open
- activated by detection device or manual
Protects: Class A and Class B fires
- Gas jet fires
- computer equipment and rooms
- flammable and combustible liquids
- aircraft passenger cabins
- marine vessels
- ordinary Class A combustibles
Describe how a foam-water system works. (523-524)
NFPA 16. Discharges foam-water solution onto a fire. Commonly for Class B but also may protect Class A hazards. When properly designed they may suppress vapors from flammable liquid spill.
- Can be wet-pipe, dry-pipe, preaction, or deluge.
- At least 15 minutes to control and suppress.
- Proportioner, in line valve or pump, designed to inject and mix foam concentrate with water
- Annual test of proportioner
Inspector verify minimum required volume of foam concentrate and correct type of foam provided and maintained.
Describe standpipe and hose systems and the standard components (526)
- Hose stations
- Water supplies
- Waterflow control valves
- Risers
- Pressure-regulating devices
- Fire Department Connections (FDCs)
Differentiate between the standpipe classifications. (526)
NFPA 14
Class I: Firefighters. Large handlines 2-1/2” hose connection. Supply effective fire streams during more advanced stages of fire.
Class II: Trained Building Occupants . 1-1/2” hose, nozzle, and hose rack. In declining favor to Class I and Class III.
Class III: Combination. Both 2-1/2” and 1-1/2” hose connections, can be used simultaneously. Typically 2-1/2” has 1-1/2” adapter.
What are the types of standpipe and hose systems? (527-529)
~ Automatic-wet, water in system at all times
~ Automatic-dry, air/nitrogen under pressure, permanently attached to water supply, water enters when hose valve opened
~ Semiautomatic-dry, empty pipe connected to permanent water supply. Device such as deluge valve admits water upon activation of remote control device at hose connection.
~ Manual-dry, domestic water in system, relies on fire department to provide water at FDC to meet demand
~ Manual-wet, maintains domestic water fill to detect leaks, relies on fire department to provide water at FDC
What are some of the inspection requirements for water supplies, standpipe hose valves, regulating devices, and fire department connections? (529-532)
- Are standpipes accessible, visible
- Do valves work
- Are caps in place
- Are doors closed and latched
- Verify inspection & maintenance records
- Be aware of secondary water supply
- Verify operational readiness of supply
- Verify standpipe pressure
- Standpipe Hose Valves within 130ft
- Pressure regulating devices where hose outlet > 175 psi
- Verify required testing for pressure regulating valves
- Verify FDC meets standards with correct connections, coupling threads, locking caps & keys
- FDC sign must indicate which floors it services
List the types of fire pumps that can be installed as stationary pumps for fire suppression systems.
NFPA 20, 5 types of centrifugal pumps:
Horizontal split-case
Vertical split-case
Vertical inline
Vertical turbine
End suction
Differentiate between the types of fire pump drivers. (535-536)
Electric Motor Driver. Most common. Simple, reliable, easily maintained. May require larger electrical service to bldg.
Diesel Engine Driver. Listed. Used when driver independent of local electrical power is needed. More complex, expensive, and more maintenance. Requires batteries to start and an on-site fuel supply. Must be equipped with overspeed shutdown devices, tachometers, oil-pressure gauges, temperature gauges. Enclosure needs adequate air flow and removal of exhaust. Tested weekly for 30 minutes.
Steam Turbine. Least common. Steam pressure to drive horizontal and vertical split-case pumps directly. Only economical if uninterruptible supply of steam is available.
Describe different types of controllers found on stationary fire pump systems. (537-538)
NFPA 20.
Electric Motor. Pressure sensing switch detects drop in pressure resulting from flow of water, which energizes a circuit that closes the contacts for the motor circuit and starts the pump motor. When water stops flowing in the system, the pressure switch interrupts the motor circuit, thereby turning off pump.
Diesel Motor. Closes the circuit for the starting motor on the diesel engine. Monitors and contains alarms for:
- low engine oil pressure
- high engine coolant temperature
- failure to start
- engine overspeed shut-down
- battery failure
What does an inspector need to do before performing an inspection, witnessing a test, or reviewing records for a water-based fire suppression system? (545)
- Review the records of previous inspections and identify the make, model, and type of equipment, including the area protected by the system
- Determine whether the occupancy classification has changed
- Review building permits for the site to determine whether any approved alterations have been made to the structure or facility
- Wear appropriate clothing for dirty locations such as attics and basements
- Obtain permission from the owner/occupant before performing any inspection
Describe the steps involved in inspecting an automatic sprinkler system.
- Verify indicating control valve opened fully and secured
- Verify indicating control valve in operating condition, accessible, undamaged
- Check PIV’s operating wrench in place, target properly adjusted, cover glass in place and clean, bolts tight and barrel casing intact
- FDC not blocked, swivels rotate freely, caps in place, keys provided, verify threads
- Automatic sprinkler protection provided throughout occupied areas
- Verify inlet and outlet gauges on riser indicating water and air pressure available in system
- Wet-pipe systems: verify freeze protection
- Dry-pipe systems: riser room heated, air compressor functional, system piping pressurized
- Verify sprinklers free from damage, corrosion, paint, not subject to recall
- Inspection, testing, maintenance report completed?
- Quarterly main drain test, verify the inspection and witness alarm test
- Dry-pipe:
- air pressure readings correspond to previously recorded, ball drip valve moves freely and allows trapped water to seep out of FDC
- velocity drip valve free to move and trapped water can seep out
- drum drips drained
- priming water correct level
- systems air pressure maintained 15-20 psi above trip point, no air leaks
- air compressor approved for sprinkler system use, maintained, operable, sufficient size
- Observe alarm-trip test performed by owner/rep’s sprinkler company rep
- inspect sprinkler cabinet has required number and type of sprinklers
- note condition and location of sprinklers, hangers, piping
- check for changes in occupancy, use, fire hazards, equipment
What are some of the conditions inspectors should check or verify when inspecting residential sprinkler systems? (552-554)
Listed piping materials, min 1/2”
Plastic piping limitations if used
Sprinkler placement and spacing
Areas that are exempt from coverage
Name some of the water-spray fixed system components inspectors need to check during an inspection.
Valves
Detection devices
Piping
Nozzles
Strainers
Water Supply
What foam-water system components should be checked during an inspection? (555)
Valves
Detection devices
Piping
Nozzles
Strainers
Water Supply
Verify valves in appropriate position for the type of proportioner in use:
~ Standard pressure, verify ball drip valves are open, operable, no corrosion on storage tanks
~ Bladder tank, check operation of waterflow control valves, no corrosion on storage tank, look for foam in water around bladder
~ Line, inspect strainers not obstructed, no corrosion on storage tank, verify pressure vacuum vent operational
~ Standard and inline balanced-pressure, strainers not obstructed, pressure vacuum vent operational, gauges operational, sensing line valves open, power available for foam pump
~ Orifice plate, same as balanced-pressure proportioners except no sensing line valves
What conditions should inspectors look for in standpipe and hose systems? (556)
- All water supply valves are sealed in open position
- Fire pump in operating condition with power available
- Hose valves free of paint, corrosion, other impediments
- Hose valves operable
- Hose valve threads not damaged
- Hose valve wheels present and not damaged
- Hose cabinets accessible
- Hose (when present) in good condition, dry, properly positioned on rack or reel
- Discharge outlets in dry systems closed
- Dry standpipe drained of moisture
- FDC not blocked, swivels rotate freely, caps in place, verify appropriate keys provided if locking, verify threads compatible with FD coupling
What are some of the inspection requirements for stationary fire pumps?
Weekly inspection (building maintenance)
Pumps should be operated from automatic starts if equipped and brought up to full speed pumping a substantial stream.
Evaluate electrical power
Visual check control panel, power is on
Flow test only way to check for obstructions
For a fire suppression system to be effective, it must be reliable and: (504)
A. automatic.
B. inexpensive.
C. less than five years old.
D. less than ten years old.
A
Most fires in sprinkler-equipped structures are controlled by the operation of: (504)
A. all of the sprinklers.
B. one or two of the sprinklers.
C. at least fifty percent of the sprinklers.
D. at least seventy-five percent of the sprinklers.
B
Which automatic sprinkler system is typically provided in areas where freezing temperatures are likely to occur? (505)
A. Dry-pipe sprinkler system
B. Wet-pipe sprinkler system
C. One-time use sprinkler system
D. Combination dry-pipe and wet-pipe system
A
All sprinklers discharge water simultaneously in: (506)
A. deluge sprinkler systems.
B. dry-pipe sprinkler systems.
C. wet-pipe sprinkler systems.
D. preaction sprinkler systems.
A