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Sprinkler
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Systems
Systems
Continuing Education rom
Continuing Education rom
Plumbing Systems & Design
Plumbing Systems & Design
OCTOBER 2011
OCTOBER 2011
PSDMAGAZINE.ORG
Automatic sprinklers were developed to control, conne, and extin-guish res in order to prevent the loss o lie and minimize the loss o property. However, the existence o a sprinkler system should not cause apathy among building owners and occupants. Flammable products, gases, liquids, or the accumulation o combustibles and other sensitive materials (e.g., explosives and rocket-propellant uels) require strict supervision and continuous prevention and control.
A “re-protection sprinkler system” is an integrated system o under-ground and overhead piping designed in accordance with re-protec-tion engineering standards. Te design and installare-protec-tion o sprinkler systems is based on NFPA Standard no. 13,Installation of Sprinkler Sys-tems. Tis standard was rst published in 1896 and is the oldest NFPA standard. It was prepared in conjunction with:
• Fire-servicepersonnel.
• Fire-insurancerepresentatives.
• Testinglaboratoriesforre-protectionitems.
• Representativesfromre-protectionequipmentmanufacturers. • Contractorswhoinstalledsuchsystems.
Due to continuous improvements made in automatic sprinkler sys-tems, NFPA Standard no. 13 evolved into Standard no. 13A,Inspection, Testing, and Maintenance of Sprinkler Systems, in 1938. In 1960, NFPA’s sprinkler committee redeveloped the sprinkler standard. As with any other code or standard, this standard gives only the minimum require-ments in order to provide a reasonable degree o protection. Based on the owner’s preerence, additional protection may be installed or a higher degree o saety.
History of sprinklers
Te rst sprinkler system in the United States was installed in 1852 and consisted o perorated pipe. Te rst automatic sprinkler was invented 12 years later. By 1895, sprinkler-system development was increasing, and the Boston area alone had nine dierent systems. Boston experi-enced the most signicant growth in this area because o the number o hazardous textile mills in the vicinity.
Beore 1950, sprinkler heads simultaneously discharged water upward and downward. Te downward movement quenched the re, while the upward movement kept the structure cool. Tese old-style
heads were replaced by upright and pendent heads.
Te current drive is to install automatic sprinkler systems even in residentialbuildings(NFPAStandardsnos.13Dand13Rcoverthese applications.)
selecting tHe type of sprinkler system
Te actors to consider (or questions to be asked by the designer) in selecting the type o sprinkler system or the type o suppression system are as ollows:
• Duetoitscontent(combustiblematerials),istheareatobepro-tected expected to develop a ast-growing re?
• Whatistheprincipalgoalofthere-suppressionsystem— occupants or content?
• Aretherevaluableitemsintheareaprotectedthatcanbedam-aged by water?
• Isthereapossibilityoffreezing?
Answering these basic questions will determine the type o suppres-sion system to be designed and i nstalled.
sprinkler Definitions
Tere are various types o xed-sprinkler system. Each system is clearly dened in NFPA Standard no. 13., and these denitions ollow.
Wet-Pipe System—Asystememployingautomaticsprinklersattached to a piping network containing water under pressure at all times and connected to a water supply so that water discharges immediately rom sprinklers opened by a re. Approximately 75% o the sprinkler systems in use are o the wet-pipe type. Tis type o sprinkler system is easy to maintain and is considered the most reliable. It is installed where there is no danger o reezing or special requirements.
Dry-Pipe Systems—A system employing automatic sprinklers attached to a piping system containing air or nitrogen under pressure, the release o which (as rom a sprinkler opening) permits the water pressure to open a valve located in the riser known as a “dry-pipe valve.” Te water then ows into the piping system and out the opened sprinklers. A dry-pipe system starts somewhat more slowly than a wet one; however, the time between the sprinkler opening and the water owing can be shortened by using quick-opening devices. Tis system is used where sprinklers are subject to reezing.
Te dry-pipe system uses a general compressed-air system or a local air compressor. Te air-supply line must have a restrictive orice with a 1/16-in. diameter. Te sprinkler-head orice must be larger than the supply-pipe opening or the air pressure will not drop and the dry valve will not open.
It should be emphasized that all components must be listed and approved.
Pre-Action System—Asystem employing automatic sprinklers that is attached to a piping system containing air that may or may not be under pressure, with a supplemental detection system installed in the same areas as the sprinklers. I the air is under pressure in the pipes, the pressure must be very low (just enough to help detect air leaks). Actuation o the detection system opens a valve, which permits water
to ow into the sprinkler piping system and to be discharged rom any sprinklers that may be open. Tis system is used where valuables are stored and accidental water discharge may cause damage.
Deluge System—Asprinklersystememployingopenheadsattached to a piping system and connected to a water supply through a (deluge) valve, which is opened by the operation o a detection system installed inthesameareasasthesprinklers.Whenthisvalveopens,waterows into the piping system and discharges rom all heads attached thereto. Tis system is used in very high-hazard areas.
Combined Dry-Pipe and Pre-Action Sprinkler System—A system employing automatic sprinklers attached to a piping system contain-ing air under pressure with a supplemental detection system installed in the same areas as the sprinklers. Operation o the detection system actuates tripping devices, which open dry-pipe valves simultane-ously and without loss o air pressure in the system. Operation o the detection system also opens approved air-exhaust valves at the end o the eed main, which usually precedes the opening o sprinklers. Te detection system also serves as an automatic re-alarm system.
Antifreeze System—Awetpipesystememployingautomaticsprin -klers attached to a piping system that contains an antireeze solution and is connected to a water supply. Te antireeze solution lls the pipes rst, ollowed by water, which discharges immediately rom
Reprinted from Fire Protection Systems. © American Society of Plumbing Engineers, 2001.
sprinklers opened by heat rom a re. Te antireeze system is no di-erent than a wet system except that the initial charge o water is mixed with antireeze. Te system may be installed in unheated areas as can a dry system. Additional devices may be required to prevent air-pocket ormation. Tis system prevents the water rom reezing in the pipes.
sprinkler operAtion
Te sprinkler system inside a building is actually a network o pipes that are sized rom either pipe schedules or hydraulic calculations. Te system is installed overhead, and sprinkler heads are attached to the pipes in a systematic pattern. Te valve controlling each system riser is located in the system riser or its supply piping.
Heat rom a re triggers the sprinkler system, causing one or more heads to open and discharge water only over the re area (except in deluge systems with permanently open heads). Each sprinkler system includes a device or activating an alarm when water starts to ow.
Studies o more than 81,000 res perormed over a 44-year period indicate that sprinklers were eective in controlling 96.2% o the res.1 Te automatic sprinkler system is a very reliable and efcient suppres-sion system because o the ollowing eatures:
• Immediatedetection. • esoundingofanalarm. • Minimalresponsetime.
• Continuousoperationuntilthereiscompletelyextinguished. Because sprinkler systems are so reliable, insurance companies reduce their rates considerably or buildings that are equipped with complete systems.
cAre AnD mAintenAnce
Sprinkler heads shall never be stored where temperatures may exceed 100°F. Sprinkler heads shall never be painted, coated, or modied in any way after leaving the manufacturing premises. Care should be exercised to avoid the damage o sprinkler heads during handling
system Design
Fire-protection design documents consist o drawings and specica-tions. Tese documents must be prepared, approved, and kept readily available or urther inspection and modications i necessary. Ater installation, a re-protection system must be inspected and tested.
Whendevelopingasprinklersystemdesign,thecoderequirescer -tain data to be listed on drawings. NFPA Standard no. 13 lists all the inormation required on the working design drawings, which includes the ollowing: • Name,location,addressofpropertyonwhichsprinklerswillbe installed. • Ownerandoccupant. • Pointofcompass(northdirection). • Typeofconstruction. • Distancefromhydrant. • Specialhazardrequirements,etc.
It is essential that sprinkler systems be designed to t the particular hazardofabuildingorstructure.NFPAStandardsnos.231and231C cover sprinkler systems or storage areas that require specic arrange-ments and specialized sprinklers.
Water Supply
An automatic sprinkler system should be connected to an automatic water-supply system, such as a municipal water main or an automatic re pump. NFPA standards do not actually speciy the type o automatic supply.
In addition to being reliable, the water supply must have the required pressure and capacity needed or the sprinkler system. Te water quan-tity or the sprinklers is determined by adding the ow requirements or the number o sprinkler heads expected to operate plus 500 gpm or a hose station (unless otherwise directed by the authority having jurisdiction).
Te number o sprinkler heads expected to operate in case o a re depends on the ollowing items:
• Occupancy.
• Combustibilityofcontent. • Height of stock pile.
• Combustibilityofconstruction. • Ceiling height. • Horizontalandverticalcutos. • Areashieldedfromproperwaterdistribution. • Typeofsprinklersystemused. Strainers
Strainers are ordinarily required in sprinkler-system supply lines where the sprinkler head orice is smaller than a in. Tey should have holes small enough to protect the smallest water passage in the nozzle or sprinkler head used. Te use o galvanized piping downstream o the deluge valve is recommended in water-spray systems so spray nozzles will not become clogged by rust.
Piping
Figure 8-1 illustrates the dierent components in an indoor-sprinkler piping network. Each component is dened as ollows:
SystemRiser—Above-groundsupplypipedirectlyconnectedtothe water supply.
Risers—Vertical pipes supplying the sprinkler system. All verti-cal pipes in a system are included in the denition o risers, with the exception o the system riser.
FeedMains—Pipessupplyingrisersorcrossmains.
Cross Mains—Pipes supplying the branch lines, either directlyor through risers.
Branch Lines—Pipes in which the sprinklers are placed, either directly or through risers.
All valves and components used in a sprinkler system must be UL listed or approved.
Figure 8-1 Indoor-Sprinkler Piping Network
Sprinkler systems or re protection may also present public-saety risks. Preventing stale water rom a re-protection system rom mixing with potable water is now a code requirement. Installing backow pre- venters in re-protection public supply or branches is a code require-ment in most states and an essential component o re-saety design and installation.
Pressure and Temperature
Sprinkler-system components are normally designed or a pressure o 175 psi, with a working pressure o 150 psi. Higher and lower design pressures may be used as required. I the pressure required in the system is higher than normal, then all system components must be rated or the higher pressure.
or plumbing make this installation mandatory in order to protect the potable water rom contamination. A schematic o the backow-pre- venter location in the water supply is shown in Figure 8-2.
sprinkler components
Tere are many components in a sprinkler system, including: • Singleormultiplewatersupply.
• Pipingundergroundandabovegroundconnectingwatersupply to overhead sprinkler heads.2
• Fittings.
• Hangersandclamps.
• Associatedhardware(controlvalves,checkvalves,alarmvalves, dry-pipe valves, deluge valves, drain valve, and pipe).
• Fire-departmentconnections(Siameseconnections). • Alarmsandannunciators.
Whileallthesedierentcomponentsarevitaltopropersystemoper -ation, the sprinkler head is one o the most important components.
Te automatic sprinkler head is a thermo-sensitive device that is automatically activated when an area reaches a predetermined tem-perature. Once this temperature is met, the sprinkler head releases a stream o water and distributes it in a specic pattern and quantity over adesignatedarea.Waterreachesthesprinklersthroughanetworkof overhead pipes, and the sprinklers are placed along the pipes at regu-lar, geometric intervals.
Restraining Elements
Under normal conditions, water discharge rom an automatic sprinkler head is restrained by a cap held tightly against the orice. Tere are two types o restraining elements that are commonly used in sprinkler heads: usible links and rangible bulbs.
In the usible-link sprinkler head, a system o levers and links, which are anchored on the sprinkler rame, press on the cap to keep it rmly in place (see Figure 8-3). Te system is constructed by using a metal alloy Whenthesprinklersystemoperatingpressureis150psiorless,the
test pressure must be 200 psi and the length o the test must be 2 hours. For any other operating pressure, the test must be the maximum oper-ating pressure plus 50 psi. I the test takes place during the winter, air may be temporarily substituted or water.
Watertemperatureinasprinklersystemmustbebetween40and 120°F. However, when water temperature exceeds 100°F, intermediate or higher-temperature sprinklers must be used.
Flushing
Ater installation, underground mains, lead-in connections, and risers must be ushed. Tis operation is very important, because actory-supplied pipes may contain dust, rust, etc., in addition to impurities collected during installation. I not eliminated, these oreign materi-alsmayblockasprinkler’soriceandrenderitinoperable.Table8-1 shows the ushing rates prescribed by NFPA Standard no. 13.
Table 8-1 Flushing Rates Pipe Size ( in.) Flow Rate (gpm)
4 400 6 750 8 1000 10 1500 12 2000 Source: NFPA Standard no. 13.
Area Limitation
Te maximum oor area that may be protected by sprinklers supplied on each system riser on any one oor (as recommended by NFPA) is as ollows: • Lighthazard:52,000ft2(4831m2) • Ordinaryhazard:52,000ft2(4831m2) • High-piledstorage:40,000ft2(3716m2) • Extra Hazard: Pipe schedule—25,000 ft2 (2323 m2) Hydraulicallycalculated—40,000ft2(3716m2) System Drainage
All sprinkler systems must be installed so that the system may be drained i necessary. I repairs or alterations are required, a main drain valvewillallowthesystemtobeemptied.Wet-pipesystemsmaybe
installed level, while dry-pipe systems must be pitched or condensate drainage. Te pitch is usually ½ in. per 10 t or short branches and ¼ in.per10ftformains.Mainsmustbepitchedatleast½in.per10ftin rerigerated areas.
Table 8-2 shows the recommended drain-pipe size as a function o the riser size. All valves and components should be UL listed or approved.
Table 8-2 Drain-Pipe Size Pipe Size (in.) Drain-Pipe Size (in.) 2 and smaller ¾ or larger
2½ to 3½ 1¼ or larger 4 and larger 2
To determine thewater-supplyrequirements for a pipeschedule, consult NFPA Standard no. 13, which gives ow rates and operational durationforlightandordinaryhazards.Rememberthatthestandard gives only minimum requirements. Better protection may be selected at an additional cost.
Te use o pipe sizes based on a pipe schedule is somewhat restricted, so the designer must check applicable codes and standards. Tere is also a nomogram that indicates the water density in gpm vs square oot area that must be considered in the calculation o wet-type systems, dependinguponthehazardtype(seeChapter10).
I the water used or domestic purposes is common with the one used or re protection, a backow preventer must be installed on the re-protectionline.Moststatecodesapplicabletoreprotectionand/
Figure 8-2 Backow-Preventer Location
with a predetermined melting point. Te metal is composed mainly o tin, lead, or cadmium (metals with low melting points). Tere are actu-ally two dierent types o usible link:
• Solder-linktype—Constructedofaeutectic3alloyoftin,lead, cadmium, and bismuth. Tese metals have sharply dened melt-ing points and, when alloyed in proper proportions, establish the operating temperature o the sprinkler.
• Frangible-pellettype—Hasapelletofeithersolderoranother eutectic metal under compression, which melts at the design temperature and releases the cap.
Te rangible-bulb restraining element is constructed o glass (see Figure 8-4). It is an enclosed bulb containing a colored liquid that does not completely ll the bulb. Tere is a small air bubble entrapped in this colored liquid. When thetemperature rises, theliquid expands and the bubble is compressed and absorbed by the liquid. As soon as the bubble disappears, the pressure in the bulb rises rapidly and at a precise, preset temperature, the bulb shatters and releases the cap. Te exact operating temperature is regulated by bubble size and the amount o liquid in the bulb. Te higher the operating temperature, the larger the bubble.
Te recommended maximum room temperature is usually closer to the operating temperature o the rangible-bulb type. Tis is because in the usible-link type, solder begins to lose its strength below the actual melting point o the usible link. I the duration o above-normal room temperature is excessive, premature sprinkler operation could occur.
Temperature Ratings
Sprinkler heads have various operating temperature ratings that are the result o standardized tests. Te rating is stamped on the soldered link or restraining element. Te rangible-bulb liquid color also indicates thesprinklerheadtemperaturerating.Table83illustratesthetemper -ature-rating color codes or usible-link and rangible-bulb automatic
sprinklers (with the exception o plated, ush, recessed, and concealed sprinkler heads) per NFPA Standard no. 13. Te color is usually applied on the rame arms.
Table 8-3 Color Codes for Fusible-Link and Frangible-Bulb Sprinklers
Ceiling Temp. Temp. Fusible- Glass-Temp. (°F) Rating (°F) Classifcation Link Color Bulb Color
100 135 to 170 Ordinary No color Orange or black or red 150 175 to 225 Intermediate White Yellow or green 225 250 to 300 High Blue Blue 300 325 to 375 Extra high Red Purple 375 400 to 475 Extra high Green Black 475 500 to 575 Ultra high Orange Black Deectors
edeectorisattachedtothesprinklerframe.Whenawaterstream is directed against the deector, it is converted into a spray o a certain shape designed to protect a dened area. Te spray pattern depends on the deector shape (see Figure 8-5). Te pattern is roughly that o a hal sphere lled with spray, in a relatively uniorm distribution o water. For example, a spray may cover a circular area having a diameter o approximately 16 t when the discharge rate is 15 gpm and the pressure is approximately 10 to 15 psi. In general, the gpm discharge is about 1.5 times the pressure required at the head (e.g., 15 psi and 22 gpm). Note: Do not use this or actual calculations.
Te water discharge rate rom a sprinkler head ollows hydraulic laws and depends on the orice size and water pressure. Te standard sprinkler head has a ½-in.diameter orice. Other orice sizes can be easily identied by a protruding extension above the deector. Te ori-ce may be o the ring-nozzle or tapered-nozzle type.
Figure 8-4 Frangible-Bulb Upright Sprinkler
Sprinkler-Head Types
Standard sprinkler heads are made or installation in an upright or pen-dent position and must be installed in the position or which they were constructed. Architects sometimes require special sprinkler types to be used or certain applications. Tere are over 20 types o commercially available sprinkler, including the ollowing:
• Upright—Normallyinstalledabovethesupplypipe. • Pendent—Installedbelowthepipe.
• Sidewall(horizontalandvertical)—Similartostandardsprinkler heads except or a special deector, which allows the discharge o water toward one side only in a pattern resembling one-quarter
o a sphere. Te orward horizontal range o about 15 t is greater than that o a standard sprinkler. For special applications, a side- wall vertical type is used.
• Extendedcoverage—Coversmorethan225ft2perhead. • Open
• Corrosionresistant—WaxorTeoncoatedbythemanufacturer toprotectagainstcorrosives.Mostlyregularpendentorupright type heads used in areas where corrosive substances are present (e.g., chlorine storage rooms and salt-water reservoirs).
• Nozzles.
• Drypendentanddryupright—Whenalimitedenclosureissub- ject to reezing, it may be connected to a wet-pipe system through
a special dry-pipe connector. • Fastorquickresponse(QR). • Quickresponse,extendedcoverage(QREC). • Quickresponse,earlysuppression(QRES). • Earlysuppression,fastresponse(ESFR). • Ornamental. • Recessed—Mostofthebodyismountedwithinarecessedhous-ing, and its operation is similar to a standard pendent sprinkler.
• Flush—Allowstheworkingpartsofthesprinklerheadtoextend below the ceiling into the area in which it is installed without aecting the heat sensitivity or the pattern o water distribution. • Concealed—Entirebody,includingoperatingmechanism,is
above a cover plate, which drops when a re occurs, exposing thermo-sensitive assembly. Deector may be xed or it may drop below the ceiling level when water ows.
• Old style. • Residential.
• On-osprinklerheads.
Figures 8-6 through 8-12 illustrate some o these dierent types o sprinkler.
WAter-DelUge sprAy system
A water-deluge spray system reers to specially designed nozzles (open head) that orce water into a predetermined pattern, particle size, velocity, and/or density. Because a water-deluge system has all the nozzles initially open, there is heavy water consumption; thereore, each hazard should be protected by its own separate system (riser).
Piping and nozzle location, with respect to the surace or zone where the deluge system is applied, is inuenced by physical arrangement. Other elements to be determined are the size o the nozzle orice to be used (the ow required), the angle o the nozzle discharge sphere, and the required water pressure.
Tere are various shapes and sizes o nozzles, including high-veloc-ity spray nozzles, which discharge in the orm o a spray-lled cone, and low-velocity nozzles, which usually deliver a much ner spray in either a spray-lled sphere or cone shape. Another type o nozzle uses a slightly tilted deector, and the angle o the spray discharge is governed by the design o the deector.
Dry-Pipe or Deluge Valve
Te dry-pipe valve or deluge valve is an important piece o equipment in dry-pipe and deluge systems. Tere are various types o valve, and while each dry-pipe valve type is o a slightly dierent design and con-struction, the operation is the same. Tis operation includes a clapper (check valve), which has special design eatures allowing air pressure on one side o the valve while the opposite side restrains higher water pressure (see Figure 8-13). When a re occurs and sprinkler heads open, the air pressure drops within the valve, opening the clapper and lling the pipes. Te valve trips an alarm when water ows through the alarm connections.
Another type o deluge valve involves the water-supply pressure exerting pressure on the clapper in the diaphragm chamber. When the activation devices operate, water rom the diaphragm chamber is released aster than it can be replenished, destroying the pressure equi-librium and allowing water to ow into the piping system.
Deluge valves are usually equipped with various trim arrange-ments or manual and/or automatic activation by an electrical signal, which can be operated either pneumatically or hydraulically. It is up to the design engineer and the owner to make the selection o the trim arrangements.
For areas where water damage and/or consumption is o great con-cern, manuacturers have built a recyclable type o deluge valve that permits automatic, remote on-o control. Te valve opens when a re occurs and automatically shuts the water o when the heat is reduced below the detector operating temperature. It has the capability o turn-ing the water back on when the set temperature is exceeded again. All other valves must be closed manually.
sprinkler instAllAtion
It is critical to determine proper sprinkler location beore installing any system. Te ollowing points must be taken i nto consideration beore a system is installed:
• Maximumprotectionareapersprinklerhead.
• Minimuminterferencetothedischargepatternsbystructuralele-ments, piping, ducts, or lighting xtures.
Figure 8-5 Various Spray Patterns
• Correct location with respect to structural elements to obtain suitable sensitiv-ity to potential res.
In general, the maximum distance between sprinklers on branches or light and ordinary hazard occupancies is 15 t. Te protected area coverage per sprinkler head, as required by NFPA Standard no. 13, is as ollows:
• Light-hazardoccupancy:168to225ft2depending on construction type.
• Ordinary-hazardoccupancy:100to130ft2. • Extra-hazardoccupancy:90to100ft2.
All codes require sprinkler systems to have devices that will sound an alarm when water ows through the risers or main supply due to a re, accidental rupture o piping, or head(s) opening. Tese devices also monitor all valves to ensure that they are in the correct operating position. Tis can be achieved by a remote signaling to a control station, sounding an alarm, or locking the valve in an open posi-tion. In other words, the devices supervise the system and sound an alarm when any tampering or undesired/unnec-essary operation is detected.
Only UL listed materials and equipment may be used in sprinkler installations. In addition, sprinkler heads must be installed in accordance with their listing, and sprin-klers must not be altered (painted or any coat o protec-tive material applied in the eld or at the job site). It is very easy to determine whether a sprinkler head is painted by the manuacturer or in the eld; i painted by the manuac-turer, the operative parts are let unpainted.
Whensprinklerheadsmustbereplaced,thesametype must be used. Tis means the same orice type and tem-perature rating, unless there are new conditions, such as a change o occupancy or structural modications (e.g., added or canceled ceiling).
AlArms
Tree basic types o alarm can be part o a sprinkler system:
1. Vane-typewaterow—Comesequippedwitha small paddle that is inserted directly into the riser pipe. Te paddle responds to water ow as low as 10 gpm, which then triggers an alarm. Tis type may be equipped with a delayed system (adjustable rom 0 to 120 seconds) to prevent alse alarms caused by normal water-pressure uctuations.
2. Mechanicalwater-owalarm(watermotorgong)— Involves a check valve that lits rom its seat when water ows. Te check valve may vary as ollows: (a)
Dierential type has a seat ring with a concentric grooveconnectedbyapipetothealarmdevice.When the clapper o the alarm valve rises to allow water to ow to the sprinklers, water enters the groove and ows to the alarm-giving device. (b) Another type has an extension arm connected to a small auxiliary pilot valve, which, in turn, is connected to the alarm system.
3. Pressure-activatedalarmswitch—Usedinconjunction with dry-pipe valves, alarm check valves, and other
types o water-control valve. It has contact elements arranged to open or close an electric circuit when subjected to increased or reduced pressure. In most cases, the motion to activate a switch is given rom a diaphragm exposed to pressure on one side and sup-ported by an adjustable spring on the other side. Te alarm or a dry-pipe sprinkler system is arranged with a connection rom the intermediate chamber o a
Figure 8-9 Pendent Sprinkler with Extra-Large Orifce
(Courtesy of The Viking Corporation) Figure 8-8 Residential Horizontal
Sidewall Sprinkler
(Courtesy of The Viking Corporation) Figure 8-6 Upright Sprinkler (Courtesy of The Viking Corporation)
Figure 8-7 Pendent Sprinkler (Courtesy of The Viking Corporation)
Figure 8-10 Upright with Large Drop Sprinkler (Courtesy of The Viking Corporation)
dry-pipevalvetoapressure-operatedalarmdevice.Whenthedry-pipe valve trips, the intermediate chamber, which normally contains air at
atmospheric pressure, lls with water at the supply pressure, which operates the alarm devices. Sometimes both an outdoor water motor gong and a pressure-operated electric switch are provided. Te alarm devices or the deluge and pre-action systems are o the same type as those used or the dry-pipe system.
Codesrequirewater-supplycontrolvalvestoindicateconditionsthat could prevent the unwanted or unnecessary operation o the sprinkler system. Tis can be achieved by using electric switches, also called “temper switches,” which can be selected or open or closed contact. Te signal that indicates valve operation is given when the valve wheel is given two turns rom the wide open position. Te restoration signal
sounds when the valve is restored to its ully open position. Tis simply cancels the temper-switch alarm.
notes
1In cases where the sprinklers were ineective, studies show the
reasons or ailure include: improper water supply or system was not adequate, valve was in the wrong position (closed instead o open), and system was taken out o operation without temporary replacements.
2Te lie line o a sprinkler system is the distribution-piping network,
which conveys the agent to the re. It must be the correct size, well con-structed, and well supported.
3 An alloy having the lowest melting point possible, which means
lower than each o the components.
Figure 8-11 Sprinkler Dimensions Figure 8-13 Deluge-Valve Schematic
Figure 8-12 Quick-Response, Specifc-Application, Upright Sprinkler
(Courtesy of The Viking Corporation)
CONTINUING EDUCATION: Automatic Sprinkler Systems
About This Issue’s Article
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Continuing Education rom
Plumbing Systems & Design
CE Questions — “Automatic Sprinkler Systems” (PSD 181)
When was the rst automatic sprinkler invented? 1. 1852 a. 1864 b. 1895 c. 1950 d.
About 75 percent o the sprinkler systems in use are o the 2. ________ type. dry-pipe a. preaction b. wet-pipe c. deluge d.
Automatic sprinkler systems are very ecient at suppressing 3.
res because they ________.
continuously operate until the re is extinguished a.
sound an audible alarm b.
immediately detect re c.
all o the above d.
The number o sprinkler heads expected to operate in case o a 4.
re depends on the ________. ceiling height
a.
combustibility o the content b.
area o the room being protected c.
both a and b d.
In an indoor sprinkler piping network, the ________ is the 5.
vertical pipe supplying the sprinkler system. eed main a. riser b. cross main c. branch line d.
At what fow rate should a 6-inch riser be fushed? 6. 400 gpm a. 750 gpm b. 1,000 gpm c. 1,500 gpm d.
In rerigerated areas, mains must be pitched at least _______ per 7. 10 eet. 1/8 inch a. ¼ inch b. ½ inch c. ¾ inch d.
A usible-link automatic sprinkler with a temperature rating o 8. 250–300°F is colored ________. white a. purple b. red c. blue d.
The diameter o a standard sprinkler head orice is ________. 9. 1/8 inch a. ¼ inch b. ½ inch c. ¾ inch d.
A water deluge spray system may use a _______ nozzle. 10.
high-velocity spray a.
slightly tilted defector b.
low-velocity spray c.
all o the above d.
One sprinkler head can protect ________ in an ordinary-hazard 11. occupancy. 15 square eet a. 90 to 100 square eet b. 100 to 130 square eet c.
none o the above d.
What type o alarm can be part o a sprinkler system? 12.
pressure-activated alarm switch a.
water motor gong b.
vane-type water fow c.
all o the above d.
Doyounditdiculttoobtaincontinuingeducationunits(CEUs)? Trough this special section in every issue o PS&D, ASPE can help you accumulatetheCEUsrequiredformaintainingyourCertiedinPlumb-ingDesign(CPD)status.
Now Online!
Te technical article you must read to complete the exam is located at www.psdmagazine.org.Justclickon“ContinuingEducation”atthetop
o the page. Te ollowing exam and application orm also may be down-loadedfromthewebsite.Readingthearticleandcompletingtheformwill allowyoutoapplytoASPEforCEUcredit.Ifyouearnagradeof90percent or higher on the test, you will be noti ied that you have logged 0.1 CEU,whichcanbeappliedtowardCPDrenewalornumerousregulatory-agencyCEprograms.(Pleasenotethatitisyourresponsibilitytodetermine theacceptancepolicyofaparticularagency.)CEUinformationwillbekept on le at the ASPE ofce or three yea rs.
Note:Indetermin ingyouranswerstotheCEquestions,useonlythematerialpre-sented in the corresponding continuing education article. Using inormation rom other materials may result in a wrong an swer.
The October 2011 continuing education article is “Auto-matic Sprinkler Systems.”
Automatic sprinklers were developed to control, con-ne, and extinguish res to prevent the loss o lie and minimize the loss o property. This chapter denes the types o xed sprinkler systems and their components, explains how sprinklers operate, details system design, installation, and maintenance procedures, and describes the associated alarms.
You may locate this article at psdmagazine.org. Read the article, complete the ollowing exam, and submit your answer sheet to the ASPE oce to potentially receive 0.1 CEU.
CONTINUING EDUCATION: Automatic Sprinkler Systems
PS&D
cu edua Aw sh
Automatic Sprinkler Systems (PSD 181)
Questions appear on page 9. Circle the answer to each question.
Q 1. A B c D Q 2. A B c D Q 3. A B c D Q 4. A B c D Q 5. A B c D Q 6. A B c D Q 7. A B c D Q 8. A B c D Q 9. A B c D Q 10. A B c D Q 11. A B c D Q 12. A B c D
Plumbing Systems & Design
Continuing Education Application Form
This orm is valid up to one year rom date o publication. The PS&D Continuing Education program is approved by ASPE or up to one contact hour (0.1 CEU) o credit per article. Participants who earn a passing score (90 percent) on the CE questions will receive a letter or certifcation within 30 days o ASPE’s receipt o the application orm. (No special certifcates will be issued.) Participants who ail and wish to retake the test should resubmit the orm along with an additional ee (i required).
1. Photocopy this orm or download it rom www.psdmagazine.org.
2. Print or type your name and address. Be sure to place your ASPE membership number in the appropriate space. 3. Answer the multiple-choice continuing education (CE) questions based on the corresponding article ound on
www.psdmagazine.org and the appraisal questions on this orm.
4. Submit this orm with payment ($35 or nonmembers o ASPE) i required by check or money order made payable to ASPE or credit card via mail (ASPE Education Credit, 2980 S. River Road, Des Plaines, IL 60018) or ax (847-296-2963).
Please print or type; this inormation will be used to process your credits.
Name ________________________________________________________________________________________________________ Title _________________________________________________ ASPE Membership No. ____________________________________ Organization __________________________________________________________________________________________________ Billing Address ________________________________________________________________________________________________ City _________________________________________ State/Province ________________________ Zip ______________________ Country ______________________________________________ E-mail _________________________________________________ Daytime telephone ____________________________________ Fax ____________________________________________________ PE State _____________________________________________ PE No. _________________________________________________
Notice or North Carolina Proessional Engineers: State regulations or registered PEs in North Carolina now require you to complete ASPE’s online CEU validation orm to be eligible or continuing education credits. Ater successully completing this quiz, just visit ASPE’s CEU Valida-tion Center at aspe.org/CEUValidaValida-tionCenter.
Aaa Qu
Automatic Sprinkler Systems (PSD 181)
1. Was the material new inormation or you?
❏Yes
❏No
2. Was the material presented clearly?
❏Yes
❏No
3. Was the material adequately covered?
❏Yes
❏No
4. Did the content help you achieve the stated objectives?
❏Yes
❏No
5. Did the CE questions help you identiy specic ways to use ideas presented in
the article?
❏Yes
❏No
6. How much time did you need to complete the CE ofering (i.e., to read the
article and answer the post-test questions)?
I am applying for the following continuing education credits: I certiy that I have read the ar ticle indicated above.
Signature
Expiration date: Continuing education credit will be given or this examination through ob 31, 2012.
Applications received ater that date will not be processed.
❏ASPE Member ❏Nonmember Each examination: $25 Each examination: $35 Limited Time: No Cost to ASPE Member
Payment: ❏Personal Check (payable to ASPE) $
❏Business or government check $
❏DiscoverCard ❏VISA ❏MasterCard ❏AMEX $
If rebilling of a credit card charge is necessary, a $25 processing fee will be charged. ASPE is hereby authorized to charge my CE examination ee to my credit card
Account Number Expiration date