Chapter 15 Supplying Fixed Fire Suppression Systems Flashcards
What is the NFPA standard for the installation of sprinkler systems
NFPA 13
NFPA 13 is based on what document
Rules and regulation for the national board of fire underwriters for sprinkler equipment, automatic and open systems, 1896
the earlier sprinkler systems were developed direct industrial buildings ____ years ago
125
what are the three general reasons motivating building owners to invest in automatic sprinkler systems
- code requirements
- insurance purposes
- general fire protection
sprinklers are very efficient one insurance company reported a failure rate of only ___. In __ fires were controlled by 1 sprinkler head. In ___ fires were controlled by
2%
29%
75%
in general fire professionals will encounter four basic types of sprinkler systems
- wet pipe systems
- dry pipe systems
- deluge systems
- pre-action systems
Sprinkler system design must establish two basic factors when determining the appropriate type a system
- type of building
2. occupancy to be protected
what are some of the variables that go into sprinkler design? (5)
- type of sprinklers
- spacing between sprinklers
- type and size of pipe
- type of pipe hangers
- type of vavles, alarms, drains, and other system components
NFPA 231 deals with
storage buildings/ sprinkler requirements
NFPA 409 deals with
aircraft hangers
NFPA 13 defines three general hazard levels for occupancies, they are
- light hazards
- ordinary hazard
- extra hazard
light hazard examples
churches, hospitals, offices, apartment
ordinary hazards are subdivided into two subclasses when are they, and what are examples of each
ordinary hazards group 1… bakery, cannery, electronic plant ( combustibles do not exceed 8 feet)
ordinary hazards group 2… serial mails, confectionery manufacturing, print processes, tire manufacturing (
extra hazard occupancies, are subdivided into two groups examples of each
extra hazard group 1… particleboard manufacturing, sawmills, textile packing
extra hazard group 2… occupancies containing flammable liquid spraying, varnish dripping, flow coating operations
what type of sprinkler systems are the most common and reliable
wet pipe sprinkler systems
the basic operational sequence for wet pipe sprinkler system:
- heat melts plug
- water flow from sprinkler head
- alarm check valve activates water gong/ electronic signaling equipment
- alarm is transmitted to fire department
- fire department suppliers FDC
basic operational sequence for dry pipe sprinklers (6)
- heat melts plug
- pressurized air escapes
- after pressure drop quick opening device accelerates air removal
- reduce pressure allows dry pipe valve to open
- water entry system, fills pipe
- water is discharged from sprinkler head
how does a deluge system differ from a dry pipe system
have no fusible links, deluge valve is activated by heat, smoke, or flame detectors… water will discharge through all sprinklers simultaneously
what type of occupancies do deluge systems protect
extra hazard occupancies
what type of occupancies do pre-action sprinkler systems protect
occupancies where preventing water damage is especially important.. computer rooms, document storage
how do deluge sprinkler systems and pre-action sprinkler systems differ
pre-action sprinkler systems, use an alarm like deluge systems, and have dry pipes like deluge systems. however pre-action systems have feasible plugs on sprinkler heads
the basic components of a sprinkler system are (5)
sprinklers piping valves water supply FDC
where the three main components of a close sprinkler that are of interest to firefighters
heat sensing device
deflector
discharge orifice
what determines the temperature at which the heat sensing device on the sprinkler head will activate
the maximum temperature expected at the level of the sprinkler under normal conditions in area protected
the most common heat sensing device temperature of activation
165°
when inspecting sprinkler heads you can quickly identify the temperature rating by
color coding on sprinkler frame/ frangible glass bulb
also stamped on link in soldered sprinklers
how can the speed of sprinkler operation be evaluated
RTI- response time index, the lower the RTI the faster it responds
what is the RTI of an ordinary sprinkler
what is the RTI of a quick- response sprinkler
225-700 feet second
50 feet second
three basic types of sprinkler design
- upright
- pendant
- sidewall
what determines the actual amount of water discharged by a sprinkler (2)
the discharge orifice
pressure available
Q= K P …stand for
Q- quantity of water
P- discharge pressure, @sprinkler head
K- discharge coefficient
the three basic types of piping used for sprinkler systems
- ferrous metal (black steel most common overall)
- copper piping
- plastic
four types of ferrous metal piping used in sprinklers
schedule 5
schedule 10
schedule 40
special lightweight
what is the main drawback for the use of plastic pipes in sprinklers
may not be installed in areas where the ambient temperature exceeds
120 polybutylene
150 CPVC
four types of indicating valves commonly used for system control valves
- OS&Y, outside screwing yoke
- PIV, post-indicating valve
- WPIV, wall post indicating valve
- indicating butterfly valve
what does NFPA 13 will require of the water supply
min residual pressure required at the most hydraulically challenge sprinkler in a pipe system schedule, 15 psi
and a hydraulic calculated system, 7 psi
3 principal causes the above unsatisfactory performance in sprinkler systems
- closed valve on water supply
- inadequate water supply to the sprinkler
- changes in occupancy, that negate the sprinklers effects
most common cause for closed water supply valve
failure to open valve after maintenance
why is it important to not use static water sources for supplying sprinkler systems
may clog sprinkler systems
rule of thumb discharge pressure that most by departments use for supplying sprinkler system FDC’s
150psi
most departments use a standard rule of thumb of____ b account for our pressure loss in the spring system
25psi
value standpipes in large one story buildings
reduces effort to advance hose lines long distances facilitating easier fire attack
five types of standpipe systems
- dry automatic standpipes
- wet automatic standpipes
- semi automatic standpipes
- dry manual standpipes
- wet manual standpipes
dry automatic standpipes
pressure in dry standpipe prevents water flow into system, opening discharged allows water in… main disadvantage large amount of air must be bled through hose
wet automatic standpipes
most common design, system has water and pressure just connect hose and open valve
semi automatic dry standpipes
requires remote control activation device before Waters allowed into the piping system, once applied has sufficient pressure and water to supply fire attack
manual dry standpipes
dry system requires supply and pressure from FDC
manual wet pipe standpipe
wet pipe system that requires supply pressure from FDC
class 1 standpipe system
for use by fire department personnel, connections for 2.5” attack lines…
class 2 standpipe systems
designed primarily for use by occupants, hose cabinets with pre-connected 1.5” handlines
100gpm @100psi
class 3 standpipe systems
features of both class I and class II systems
standpipe piping must be able to withstand pressures of up to
300psi
standpipe hose connections must be within___ of the floor
3-5ft
travel distance to any point on the floor protected by class 1 standpipe shall not exceed ___ un-sprinklered, and ___ sprinklered
150ft
200ft
class 2 discharges and hose cabinets should be located so the travel distance on any part of the floor is no more than ___ (1.5” hose), and ____ (
130ft
120ft
NFPA 14 requires up PRD when hose outlet exceeds ___for 1.5” discharges and ___ for 2.5” discharges
100psi (1.5”)
175psi (2.5”)
what is the height beyond which fire department pumpers can effectively supply water without special high-pressure pumpers is
450ft
what NFPA standard states that there shall be no shutoff valve between the fire department connection and the standpipe riser
NFPA 14
for what pressure and how long should a standpipe be hydrostaticly tested
200 psi
2 hours
this NFPA standard states that pressure regulating devices should be tested annually
NFPA 14
NFPA 14 states that at no time should the standpipe be supplied with more than __
200psi
