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Automatic

Automatic

Sprinkler

Sprinkler

Systems

Systems

Continuing Education rom

Continuing Education rom

Plumbing Systems & Design

Plumbing Systems & Design

OCTOBER 2011

OCTOBER 2011

PSDMAGAZINE.ORG

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 Automatic sprinklers were developed to control, conne, and extin-guish res in order to prevent the loss o lie 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 installare-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-servicepersonnel.

• Fire-insurancerepresentatives.

• Testinglaboratoriesforre-protectionitems.

• Representativesfromre-protectionequipmentmanufacturers. • Contractorswhoinstalledsuchsystems.

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 preerence, additional protection may be installed or a higher degree o saety.

History of sprinklers

Te rst sprinkler system in the United States was installed in 1852 and consisted o perorated pipe. Te rst automatic sprinkler was invented 12 years later. By 1895, sprinkler-system development was increasing, and the Boston area alone had nine dierent systems. Boston experi-enced the most signicant growth in this area because o the number o  hazardous textile mills in the vicinity.

Beore 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 residentialbuildings(NFPAStandardsnos.13Dand13Rcoverthese 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:

• Duetoitscontent(combustiblematerials),istheareatobepro-tected expected to develop a ast-growing re?

• Whatistheprincipalgoalofthere-suppressionsystem— occupants or content?

• Aretherevaluableitemsintheareaprotectedthatcanbedam-aged by water?

• Isthereapossibilityoffreezing?

 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  dened in NFPA Standard no. 13., and these denitions ollow.

Wet-Pipe System—Asystememployingautomaticsprinklersattached 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 orice with a 1/16-in. diameter. Te sprinkler-head orice 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—Asystem 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—Asprinklersystememployingopenheadsattached 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 inthesameareasasthesprinklers.Whenthisvalveopens,waterows 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—Awetpipesystememployingautomaticsprin -klers attached to a piping system that contains an antireeze solution and is connected to a water supply. Te antireeze solution lls the pipes rst, ollowed by water, which discharges immediately rom

Reprinted from Fire Protection Systems. © American Society of Plumbing Engineers, 2001.

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sprinklers opened by heat rom a re. Te antireeze system is no di-erent than a wet system except that the initial charge o water is mixed  with antireeze. 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 perormed over a 44-year period indicate that sprinklers were eective 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:

• Immediatedetection. • esoundingofanalarm. • Minimalresponsetime.

• Continuousoperationuntilthereiscompletelyextinguished. 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 modied 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 specica-tions. Tese documents must be prepared, approved, and kept readily  available or urther inspection and modications i necessary. Ater installation, a re-protection system must be inspected and tested.

 Whendevelopingasprinklersystemdesign,thecoderequirescer -tain data to be listed on drawings. NFPA Standard no. 13 lists all the inormation required on the working design drawings, which includes the ollowing: • Name,location,addressofpropertyonwhichsprinklerswillbe installed. • Ownerandoccupant. • Pointofcompass(northdirection). • Typeofconstruction. • Distancefromhydrant. • Specialhazardrequirements,etc.

It is essential that sprinkler systems be designed to t the particular hazardofabuildingorstructure.NFPAStandardsnos.231and231C cover sprinkler systems or storage areas that require specic 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 speciy 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.

• Combustibilityofcontent. • Height of stock pile.

• Combustibilityofconstruction. • Ceiling height. • Horizontalandverticalcutos. • Areashieldedfromproperwaterdistribution. • Typeofsprinklersystemused. Strainers

Strainers are ordinarily required in sprinkler-system supply lines where the sprinkler head orice 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 dierent components in an indoor-sprinkler piping network. Each component is dened as  ollows:

SystemRiser—Above-groundsupplypipedirectlyconnectedtothe  water supply.

Risers—Vertical pipes supplying the sprinkler system. All verti-cal pipes in a system are included in the denition o risers, with the exception o the system riser.

FeedMains—Pipessupplyingrisersorcrossmains.

Cross Mains—Pipes supplying the branch lines, either directlyor 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-saety  risks. Preventing stale water rom a re-protection system rom mixing  with potable water is now a code requirement. Installing backow pre- venters in re-protection public supply or branches is a code require-ment in most states and an essential component o re-saety 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.

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or plumbing make this installation mandatory in order to protect the potable water rom contamination. A schematic o the backow-pre- venter location in the water supply is shown in Figure 8-2.

sprinkler components

Tere are many components in a sprinkler system, including: • Singleormultiplewatersupply.

• Pipingundergroundandabovegroundconnectingwatersupply to overhead sprinkler heads.2

• Fittings.

• Hangersandclamps.

• Associatedhardware(controlvalves,checkvalves,alarmvalves, dry-pipe valves, deluge valves, drain valve, and pipe).

• Fire-departmentconnections(Siameseconnections). • Alarmsandannunciators.

 Whileallthesedierentcomponentsarevitaltopropersystemoper -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 specic pattern and quantity over adesignatedarea.Waterreachesthesprinklersthroughanetworkof 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 orice. 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   Whenthesprinklersystemoperatingpressureis150psiorless,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.

 Watertemperatureinasprinklersystemmustbebetween40and 120°F. However, when water temperature exceeds 100°F, intermediate or higher-temperature sprinklers must be used.

Flushing

 Ater 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-alsmayblockasprinkler’soriceandrenderitinoperable.Table8-1 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: • Lighthazard:52,000ft2(4831m2) • Ordinaryhazard:52,000ft2(4831m2) • High-piledstorage:40,000ft2(3716m2) • Extra Hazard: Pipe schedule—25,000 ft2 (2323 m2) Hydraulicallycalculated—40,000ft2(3716m2) 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  valvewillallowthesystemtobeemptied.Wet-pipesystemsmaybe

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.per10ftformains.Mainsmustbepitchedatleast½in.per10ftin rerigerated 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 thewater-supplyrequirements for a pipeschedule, consult NFPA Standard no. 13, which gives ow rates and operational durationforlightandordinaryhazards.Rememberthatthestandard 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, dependinguponthehazardtype(seeChapter10).

I the water used or domestic purposes is common with the one used or re protection, a backow preventer must be installed on the re-protectionline.Moststatecodesapplicabletoreprotectionand/

Figure 8-2 Backow-Preventer Location

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 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 dierent types o usible link:

• Solder-linktype—Constructedofaeutectic3alloyoftin,lead, cadmium, and bismuth. Tese metals have sharply dened melt-ing points and, when alloyed in proper proportions, establish the operating temperature o the sprinkler.

• Frangible-pellettype—Hasapelletofeithersolderoranother 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 thetemperature rises, theliquid 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 thesprinklerheadtemperaturerating.Table83illustratesthetemper -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 Deectors

edeectorisattachedtothesprinklerframe.Whenawaterstream is directed against the deector, it is converted into a spray o a certain shape designed to protect a dened area. Te spray pattern depends on the deector shape (see Figure 8-5). Te pattern is roughly that o a hal  sphere lled with spray, in a relatively uniorm 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 orice size and water pressure. Te standard sprinkler head has a ½-in.diameter orice. Other orice sizes can be easily identied by a protruding extension above the deector. Te ori-ce may be o the ring-nozzle or tapered-nozzle type.

Figure 8-4 Frangible-Bulb Upright Sprinkler

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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—Normallyinstalledabovethesupplypipe. • Pendent—Installedbelowthepipe.

• Sidewall(horizontalandvertical)—Similartostandardsprinkler heads except or a special deector, 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.

• Extendedcoverage—Coversmorethan225ft2perhead. • Open

• Corrosionresistant—WaxorTeoncoatedbythemanufacturer toprotectagainstcorrosives.Mostlyregularpendentorupright type heads used in areas where corrosive substances are present (e.g., chlorine storage rooms and salt-water reservoirs).

• Nozzles.

• Drypendentanddryupright—Whenalimitedenclosureissub- ject to reezing, it may be connected to a wet-pipe system through

a special dry-pipe connector. • Fastorquickresponse(QR). • Quickresponse,extendedcoverage(QREC). • Quickresponse,earlysuppression(QRES). • Earlysuppression,fastresponse(ESFR). • Ornamental. • Recessed—Mostofthebodyismountedwithinarecessedhous-ing, and its operation is similar to a standard pendent sprinkler.

• Flush—Allowstheworkingpartsofthesprinklerheadtoextend below the ceiling into the area in which it is installed without aecting the heat sensitivity or the pattern o water distribution. • Concealed—Entirebody,includingoperatingmechanism,is

above a cover plate, which drops when a re occurs, exposing thermo-sensitive assembly. Deector may be xed or it may drop below the ceiling level when water ows.

• Old style. • Residential.

• On-osprinklerheads.

Figures 8-6 through 8-12 illustrate some o these dierent types o  sprinkler.

WAter-DelUge sprAy system

 A water-deluge spray system reers 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; thereore, each hazard should be protected by its own separate system (riser).

Piping and nozzle location, with respect to the surace or zone where the deluge system is applied, is inuenced by physical arrangement. Other elements to be determined are the size o the nozzle orice 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 deector, and the angle o the spray discharge is governed by the design o the deector.

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 dierent 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, manuacturers 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 beore installing any  system. Te ollowing points must be taken i nto consideration beore a system is installed:

• Maximumprotectionareapersprinklerhead.

• Minimuminterferencetothedischargepatternsbystructuralele-ments, piping, ducts, or lighting xtures.

Figure 8-5 Various Spray Patterns

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• 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-hazardoccupancy:168to225ft2depending on construction type.

• Ordinary-hazardoccupancy:100to130ft2. • Extra-hazardoccupancy:90to100ft2.

 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 manuacturer or in the eld; i painted by the manuac-turer, the operative parts are let unpainted.

 Whensprinklerheadsmustbereplaced,thesametype must be used. Tis means the same orice type and tem-perature rating, unless there are new conditions, such as a change o occupancy or structural modications (e.g., added or canceled ceiling).

AlArms

Tree basic types o alarm can be part o a sprinkler system:

1. Vane-typewaterow—Comesequippedwitha 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. Mechanicalwater-owalarm(watermotorgong)— Involves a check valve that lits rom its seat when  water ows. Te check valve may vary as ollows: (a)

Dierential type has a seat ring with a concentric grooveconnectedbyapipetothealarmdevice.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-activatedalarmswitch—Usedinconjunction  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)

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dry-pipevalvetoapressure-operatedalarmdevice.Whenthedry-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.

Codesrequirewater-supplycontrolvalvestoindicateconditionsthat 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 ineective, 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 lie 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)

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CONTINUING EDUCATION: Automatic Sprinkler Systems

About This Issue’s Article

   P

   S

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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 ecient 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 rerigerated 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 orice 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.

Doyounditdiculttoobtaincontinuingeducationunits(CEUs)? Trough this special section in every issue o PS&D, ASPE can help you accumulatetheCEUsrequiredformaintainingyourCertiedinPlumb-ingDesign(CPD)status.

Now Online!

Te technical article you must read to complete the exam is located at  www.psdmagazine.org.Justclickon“ContinuingEducation”atthetop

o the page. Te ollowing exam and application orm also may be down-loadedfromthewebsite.Readingthearticleandcompletingtheformwill allowyoutoapplytoASPEforCEUcredit.Ifyouearnagradeof90percent or higher on the test, you will be noti ied that you have logged 0.1 CEU,whichcanbeappliedtowardCPDrenewalornumerousregulatory-agencyCEprograms.(Pleasenotethatitisyourresponsibilitytodetermine theacceptancepolicyofaparticularagency.)CEUinformationwillbekept on le at the ASPE ofce or three yea rs.

Note:Indetermin ingyouranswerstotheCEquestions,useonlythematerialpre-sented in the corresponding continuing education article. Using inormation 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 lie and minimize the loss o property. This chapter denes 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 oce to potentially receive 0.1 CEU.

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CONTINUING EDUCATION: Automatic Sprinkler Systems

PS&D

cu edua Aw 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

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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 inormation will be used to process your credits.

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Notice or North Carolina Proessional 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. Ater successully completing this quiz, just visit ASPE’s CEU Valida-tion Center at aspe.org/CEUValidaValida-tionCenter.

Aaa Qu

Automatic Sprinkler Systems (PSD 181)

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article and answer the post-test questions)?

I am applying for the following continuing education credits: I certiy that I have read the ar ticle indicated above.

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References

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