Automatic Sprinkler Systems
5 3 1 D S P
Continuing Education rom Plumbing Systems & Design Kenneth G.Wentink, PE, CPD, and Robert D. Jackson
SEPTEMBER/OCTOBER SEPTEMBER/OCT OBER 2006
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CONTINUING EDUCATION
Automatic Sprinkler Systems Automatic sprinklers were developed to control, conne, and extinguish 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 underground and overhead piping designed in accordance with re-protection engineering standards. Te design and installation o sprinkler systems is based on NFPA Standard no. 13, Installation o Sprinkler Systems. 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. • esting laboratories or re-protection items. • Representatives rom re-protection equipment manuacturers. • Contractors who installed such systems. Due to continuous improvements made in automatic sprinkler systems, NFPA Standard no. 13 evolved into Standard no. 13A, Inspection, Testing, and Maintenance o 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 requirements in order to pro vide 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 experienced 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 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 protected expected to develop a ast-growing re? • What is the principal goal o the re-suppression system— occupants or content? • Are there valuable items in the area protected that can be damaged by water? • Is there a possibility o reezing? Answering these basic questions will determine the type o suppression system to be designed and installed. 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—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 orice with a z-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—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 sprin-
Reprinted from Fire Protection Systems, Chapter 8: “Automatic Sprinkler Systems,” by Justin Duncan. © American Society of Plumbing Engineers.
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klers 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 containing 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 simultaneously 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 wet-pipe system employing automatic sprinklers 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 sprinklers opened by heat rom a re. Te antireeze system is no dierent 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.
Care should be exercised to avoid the damage o sprinkler heads during handling system Design Fire-protection design documents consist o drawings and specications. 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. When developing a sprinkler-system design, the code requires certain 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, address o property on which sprinklers will be installed. • Owner and occupant. • Point o compass (north direction). • ype o construction. • Distance rom hydrant. • Special hazard requirements, etc. It is essential that sprinkler systems be designed to t the particular hazard o a building or structure. NFPA Standards nos. 231 and 231C cover sprinkler systems or storage areas that require specic arrangements 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. sprinkler operation In addition to being reliable, the water supply must have the Te sprinkler system inside a building is actually a network o pipes that are sized rom either pipe schedules or hydraulic required pressure and capacity needed or the sprinkler system. calculations. Te system is installed overhead, and sprinkler Te water quantity or the sprinklers is determined by adding the heads are attached to the pipes in a systematic pattern. Te ow requirements or the number o sprinkler heads expected valve controlling each system riser is located in the system riser to operate plus 500 gpm or a hose station (unless otherwise directed by the authority having jurisdiction). or its supply piping. Te number o sprinkler heads expected to operate in case o Heat rom a re triggers the sprinkler system, causing one or more heads to open and discharge water only over the re area a re depends on the ollowing items: (except in deluge systems with permanently open heads). Each • Occupancy. sprinkler system includes a device or activating an alarm when • Combustibility o content. water starts to ow. • Height o stock pile. Studies o more than 81,000 res perormed over a 44-year • Combustibility o construction. period indicate that sprinklers were eective in controlling • Ceiling height. 96.2% o the res.1 Te automatic sprinkler system is a very reliable and efcient suppression system because o the ollowing • Horizontal and vertical cutos. • Area shielded rom proper water distribution. eatures: • Immediate detection. • ype o sprinkler system used. • Te sounding o an alarm. strainers • Minimal response time. Strainers are ordinarily required in sprinkler-system supply • Continuous operation until the re is completely extinlines where the sprinkler head orice is smaller than a in. Tey guished. should have holes small enough to protect the smallest water Because sprinkler systems are so reliable, insurance com- passage in the nozzle or sprinkler head used. Te use o galvapanies reduce their rates considerably or buildings that are nized piping downstream o the deluge valve is recommended in water-spray systems so spray nozzles will not become clogged equipped with complete systems. by rust. care anD maintenance Sprinkler heads shall never be stored where temperatures may piping exceed 100°F. Sprinkler heads shall never be painted, coated, or Figure 1 illustrates the dierent components in an indoor-sprinmodied in any way ater leaving the manuacturing premises. kler piping network. Each component is dened as ollows:
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CONTINUING EDUCATION: Automatic Sprinkler Systems System Riser—Above-ground supply pipe directly connected
render it inoperable. able 1 shows the ushing rates prescribed by NFPA Standard no. 13.
to the water supply. Risers—Vertical pipes supplying the sprinkler system. All verTable 1 Flushing Rates tical pipes in a system are included in the denition o risers, Pipe Size Flow Rate with the exception o the system riser. ( in.) (gpm) Feed Mains—Pipes supplying risers or cross mains. 4 400 Cross Mains —Pipes supplying the branch lines, either directly 6 750 or through risers. 8 1000 Branch Lines—Pipes in which the sprinklers are placed, 10 1500 either directly or through risers. 12 2000 All valves and components used in a sprinkler system must be Source: NFPA Standard no. 13. UL listed or approved. Sprinkler systems or re protection may also present public- area limitation saety risks. Preventing stale water rom a re-protection system Te maximum oor area that may be protected by sprinklers rom mixing with potable water is now a code requirement. supplied on each system riser on any one oor (as recomInstalling backow preventers in re-protection public supply mended by NFPA) is as ollows: • Light hazard: 52,000 t2 (4831 m2) • Ordinary hazard: 52,000 t2 (4831 m2) Figure 1 Indoor-Sprinkler Piping Network • High-piled storage: 40,000 t2 (3716 m2) • Extra Hazard: Pipe schedule—25,000 t2 (2323 m2) Hydraulically calculated—40,000 t2 (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 t or mains. Mains must be pitched at least ½ in. per 10 t in rerigerated areas. able 2 shows the recommended drain-pipe size as a unction o the riser size. All valves and components should be UL listed or approved. Table 2 Drain-Pipe Size
or branches is a code requirement 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. 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 operating 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
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 materials may block a sprinkler’s orice and
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Pipe Size (in.)
Drain-Pipe Size (in.)
2 and smaller
¾ or larger
2½ to 3½
1¼ or larger
4 and larger
2
o determine the water-supply requirements or a pipe schedule, consult NFPA Standard no. 13, which gives ow rates and operational duration or 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 backow preventer must be installed on the re-protection line. Most state codes applicable to re protection and/or plumbing make this installation mandatory in order to protect the potable water rom contamination. A schematic o the backow-preventer location in the water supply is shown in Figure 2. PSDMAGAZINE.ORG
Figure 2 Backow-Preventer Location
Figure 3 Fusible-Link Upright Sprinkler
In the usible-link sprinkler head, a system o levers and links, sprinkler components Tere are many components in a sprinkler system, including: which are anchored on the sprinkler rame, press on the cap to keep it rmly in place (see Figure 3). Te system is constructed • Single or multiple water supply. by using a metal alloy with a predetermined melting point. Te • Piping underground and above ground connecting water metal is composed mainly o tin, lead, or cadmium (metals with supply to overhead sprinkler heads.2 low melting points). Tere are actually two dierent types o us• Fittings. ible link: • Hangers and clamps. • Solder-link type—Constructed o a eutectic3 alloy o tin, • Associated hardware (control valves, check valves, alarm lead, cadmium, and bismuth. Tese metals have sharply valves, dry-pipe valves, deluge valves, drain valve, and dened melting points and, when alloyed in proper proporpipe). tions, establish the operating temperature o the sprinkler. • Fire-department connections (Siamese connections). • Frangible-pellet type—Has a pellet o either solder or another eutectic metal under compression, which melts at • Alarms and annunciators. the design temperature and releases the cap. While all these dierent components are vital to proper system Te rangible-bulb restraining element is constructed o operation, the sprinkler head is one o the most important com- glass (see Figure 4). It is an enclosed bulb containing a colponents. ored liquid that does Te automatic sprinkler head is a thermo-sensitive device not completely ll the that is automatically activated when an area reaches a predeter- bulb. Tere is a small Figure 4 Frangible-Bulb Upright Sprinkler mined temperature. Once this temperature is met, the sprinkler air bubble entrapped head releases a stream o water and distributes it in a specic in this colored liquid. pattern and quantity over a designated area. Water reaches the When the temperasprinklers through a network o overhead pipes, and the sprin- ture rises, the liquid klers are placed along the pipes at regular, geometric intervals. expands and the bubble is compressed restraining elements Under normal conditions, water discharge rom an auto- and absorbed by the matic sprinkler head is restrained by a cap held tightly against liquid. As soon as the the orice. Tere are two types o restraining elements that are bubble disappears, the commonly used in sprinkler heads: usible links and rangible pressure in the bulb rises rapidly and at a bulbs. precise, preset temSEPTEMBER/OCTOBER 2006
Plumbing Systems & Design
CONTINUING EDUCATION: Automatic Sprinkler Systems perature, 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.
Figure 5 Various Spray Patterns
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. able 8-3 illustrates the temperature-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 3 Color Codes or Fusible-Link and Frangible-Bulb Sprinklers Ceiling Temp. (°F) 100 150 225 300 375 475
Temp. Temp. Fusible-Link Rating (°F) Classifcation Color Glass-Bulb Color 135 to 170 Ordinary No color or black Orange or red 175 to 225 Intermediate White Yellow or green 250 to 300 High Blue Blue 325 to 375 Extra high Red Purple 400 to 475 Extra high Green Black 500 to 575 Ultra high Orange Black
Deflectors
Te deector is attached to the sprinkler rame. When a water stream 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 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 orice may be o the ring-nozzle or tapered-nozzle type. sprinkler-HeaD types
Standard sprinkler heads are made or installation in an upright or pendent 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.
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• Sidewall (horizontal and vertical)—Similar to standard sprinkler 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 or ward horizontal range o about 15 t is greater than that o a standard sprinkler. For special applications, a sidewall vertical type is used. • Extended coverage—Covers more than 225 t2 per head. • Open • Corrosion resistant —Wax or eon coated by the manuacturer 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 subject to reezing, it may be connected to a wet-pipe system through a special dr y-pipe connector. • Fast or quick response (QR). • Quick response, extended coverage (QREC). • Quick response, early suppression (QRES). • Early suppression, ast response (ESFR). • Ornamental. • Recessed —Most o the body is mounted within a recessed housing, and its operation is similar to a standard pendent sprinkler. • Flush—Allows the working parts o the sprinkler head to extend below the ceiling into the area in which it is installed PSDMAGAZINE.ORG
Figure 6 Upright Sprinkler
Figure 7 Pendent Sprinkler
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Figure 8 Residential Horizontal Sidewall Sprinkler
Figure 10 Upright with Large Drop Sprinkler
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Figure 9 Pendent Sprinkler with Extra-Large Orifce
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Figure 11 Sprinkler Dimensions
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without aecting 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. Deector may be xed or it may drop below the ceiling level when water ows. • Old style. • Residential. • On-o sprinkler heads. Figures 6 through 12 illustrate some o these dierent types o sprinkler.
Figure 12 Quick-Response, SpecifcApplication, Upright 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 Tere are various shapes and sizes o nozzles, including higharrangement. Other elements to be determined are the size o velocity spray nozzles, which discharge in the orm o a spraythe nozzle orice to be used (the ow required), the angle o the lled cone, and low-velocity nozzles, which usually deliver a nozzle discharge sphere, and the required water pressure. much ner spray in either a spray-lled sphere or cone shape. n o i t a r o p r o C g n i k i V e h T f o y s e t r u o C
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CONTINUING EDUCATION: Automatic Sprinkler Systems Another type o nozzle uses a slightly tilted deector, and the angle o the spray discharge is governed by the design o the deector.
Figure 13 Deluge-Valve Schematic
Dry-pipe or Deluge ValVe
• Ordinary-hazard occupancy : 100 to 130 t2. • Extra-hazard occupancy : 90 to 100 t2. 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 position. In other words, the devices supervise the system and sound an alarm when any tampering or undesired/unnecessary 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 sprinklers must not be altered (painted or any coat o protective 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 manuacturer, the operative parts are let unpainted. When sprinkler heads must be replaced, the same type must be used. Tis means the same orice type and temperature rating, unless there are new conditions, such as a change o occupancy or structural modications (e.g., added or canceled ceiling).
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 construction, 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 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 equilibrium and allowing water to ow alarms into the piping system. Tree basic types o alarm can be part o a sprinkler system: Deluge valves are usually equipped with various trim arrange1. Vane-type water fow—Comes equipped with a ments or manual and/or automatic activation by an electrical small paddle that is inserted directly into the riser signal, which can be operated either pneumatically or hydraulipipe. Te paddle responds to water ow as low as cally. It is up to the design engineer and the owner to make the 10 gpm, which then triggers an alarm. Tis type may selection o the trim arrangements. be equipped with a delayed system (adjustable rom For areas where water damage and/or consumption is o great 0 to 120 seconds) to prevent alse alarms caused by concern, manuacturers have built a recyclable type o deluge normal water-pressure uctuations. valve that permits automatic, remote on-o control. Te valve 2. Mechanical water-fow alarm (water motor gong)— opens when a re occurs and automatically shuts the water o Involves a check valve that lits rom its seat when when the heat is reduced below the detector operating temper water ows. Te check valve may vary as ollows: ature. It has the capability o turning the water back on when (a) Dierential type has a seat ring with a concentric the set temperature is exceeded again. All other valves must be groove connected by a pipe to the alarm device. When closed manually. the clapper o the alarm valve rises to allow water to ow to the sprinklers, water enters the groove and sprinkler installation ows to the alarm-giving device. (b) Another type It is critical to determine proper sprinkler location beore has an extension arm connected to a small auxiliary installing any system. Te ollowing points must be taken into pilot valve, which, in turn, is connected to the alarm consideration beore a system is installed: system. • Maximum protection area per sprinkler head. 3. Pressure-activated alarm switch—Used in conjunc• Minimum intererence to the discharge patterns by struction with dry-pipe valves, alarm check valves, and tural elements, piping, ducts, or lighting xtures. other types o water-control valve. It has contact ele• Correct location with respect to structural elements to ments arranged to open or close an electric circuit obtain suitable sensitivity to potential res. when subjected to increased or reduced pressure. In In general, the maximum distance between sprinklers on most cases, the motion to activate a switch is given branches or light and ordinary hazard occupancies is 15 t. Te rom a diaphragm exposed to pressure on one side protected area coverage per sprinkler head, as required by NFPA and supported by an adjustable spring on the other Standard no. 13, is as ollows: side. • Light-hazard occupancy : 168 to 225 t2 depending on construction type.
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Te alarm or a dry-pipe sprinkler system is arranged with a connection rom the intermediate chamber o a 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 1
In 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.
2
The lie line o a sprinkler system is the distribution-piping network, which conveys the agent to the fre. It must be the correct size, well constructed, and well supported.
3
An alloy having the lowest melting point possible, which means lower than each o the components.
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CONTINUING EDUCATION
Continuing Education rom Plumbing Systems & Design Kenneth G.Wentink, PE, CPD, and Robert D. Jackson Do you nd it difcult to obtain continuing education units (CEUs)? Trough this special section in every issue o PS&D, ASPE can help you accumulate the CEUs required or maintaining your Certied in Plumbing Design (CPD) status.
About This Issue’s Article The September/October 2006 continuing education article is “Automatic Sprinkler Systems,” Chapter 8 o Fire Protection Systems by Justin Duncan. This chapter discusses the dierent types o sprinkler systems and where to use them; system design requirements including water pressure and temperature, piping, area limitations, drainage; sprinkler temperature ratings; installation parameters; and alarm systems. The inormation is based on NFPA 13: Standard for the Installation of Sprinkler Systems. Factors to consider when selecting a sprinkler system, as well as care and maintenance tips, are included.
Now Online!
Te technical article you must read to complete the exam is located at www.psdmagazine.org. Te ollowing exam and application orm also may be downloaded rom the Web site. Reading the article and completing the orm will allow you to apply to ASPE or CEU credit. For most people, this process will require approximately one hour. I you earn a grade o 90 percent or higher on the test, you will be notied that you have logged 0.1 CEU, which can be applied toward the CPD renewal requirement or numerous regulatory-agency CE programs. (Please note that it is your responsibility to determine the acceptance policy o a particular agency.) CEU inormation will be kept on le at the ASPE ofce or three years.
You may locate this article at www.psdmagazine.org. Read the article, complete the ollowing exam, and submit your answer sheet to the ASPE oice to potentially receive 0.1 CEU.
Note: In determining your answers to the CE questions, use only the material presented in the corresponding continuing education article. Using inormation rom other materials may result in a wrong answer.
CE Questions—“Automatic Sprinkler Systems” (PSD 135) 1.
In cases where the sprinklers were ineective, studies show the reasons or ailure include ___________. a. improper water supply or system was not adequate b. a valve was in the wrong position (closed vs. open) c. the system was taken out o operation without temporary replacement d. all o the above
.
A cross main is connected to ___________. a. sprinkler branch lines b. riser nipples c. eed main d. all o the above
.
An antireeze sprinkler system contains ___________. a. closed sprinkler heads b. an oil-based solution in the piping distribution network c. a ast-acting deluge valve d. a supplemental detection system
.
The sprinkler head is ___________. a. a thermo-sensitive device that is automatically activated when an area reaches a predetermined temperature b. one o the most important components o a sprinkler system c. ed rom overhead piping d. all o the above
.
A deluge-type sprinkler system consists o ___________. a. closed glass bulb sprinkler heads b. closed usible link sprinkler heads c. open pipe ends d. open sprinkler heads
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Frangible-bulb restraining elements are constructed o liquidflled glass. The colored liquid ___________. a. may be selected to match the decor o the room where it is installed b. indicates the temperature rating c. completely flls the bulb d. is o no importance to the operation o the sprinkler as it is only a manuacturer’s trademark
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NFPA 1 requires sprinkler coverage as ollows _____________. a. light hazard: 130–225 t2 b. ordinary hazard: 100–168 t2 c. extra hazard: 90–130 t2 d. none o the above is correct
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Premature sprinkler operation could occur in a usible linktype sprinkler system because ___________. a. the duration o the above-normal room temperature is excessive because the link begins to lose its strength beore the actual melting point is reached b. they are considered substandard and are rarely used c. the exact operating temperature can not be determined d. they are unreliable
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The frst automatic sprinkler system was invented in ________. a. 1852, b. 1864, c. 1876, d. 1888
10. The number o sprinkler heads expected to operate in case o a fre depends on the ___________. a. fre pump capacity b. water pressure in the street main c. type o sprinkler system used d. pipe size 11. Extra-high temperature classifcation or usible link sprinklers are color coded as ___________. a. blue or red b. red or green c. green or orange d. none o the colors noted are an exact match or this question
1. NFPA standards _______ and ________ cover sprinkler systems or storage areas that require specifc arrangements and specialized sprinklers. a. 13 and 13R b. 105 and 105B c. 231 and 231C d. none o the above
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PS&D Continuing Education Answer Sheet Automatic Sprinkler Systems (PSD 135) Questions appear on page 10. Circle the answer to each question. Q 1. A B C D Q . A B C D Q . A B C D Q . A B C D Q . A B C D Q . A B C D Q . A B C D Q . A B C D Q . A B C D Q 10. A B C D Q 11. A B C D Q 1. A B C D
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Appraisal Questions 1. 2. 3. 4. 5. 6.
Automatic Sprinkler Systems (PSD 135) Was the material new inormation or you? ❏ Yes ❏ No Was the material presented clearly? ❏ Yes ❏ No Was the material adequately covered? ❏ Yes ❏ No Did the content help you achieve the stated objectives? ❏ Yes ❏ No Did the CE questions help you identiy specic ways to use ideas presented in the article? ❏ Yes ❏ No How much time did you need to complete the CE ofering (i.e., to read the article and answer the post-test questions)? __________________
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