DESIGN OF SPRINKLER SYSTEM
A LECTURE DELIVERED DURING THE PSPE LUZON CONVENTION ON OCTOBER 17-18, BAGUIO CITY
BY JESSIE M. MARIANO MARIANO
DESIGN OF SPRINKLER SYSTEM HYDRAULIC CALCULATION CALCULATION Purpose of Hydraul! Cal!ula"o#s in fire extinguishing systems are:
a. To find the the amount of of water in in GPM (CMH) (CMH) and the pressure pressure in PSI PSI (Pa) that that is reuired reuired to meet a gi!en standard or spe"ifi"ation# at a gi!en point of supp$y. %. To find the type and "apa"ity of supp$y reuired to meet demand. ". To ena%$e the the system system to %e designed designed so that that ea"h head head wi$$ wi$$ dis"harge dis"harge the the amount of of water reuired# and within the !ariation permitted# %y the standards or spe"ifi"ations app$i"a%$e. Reaso#s for Hydraul! Cal!ula"o# in fire extinguishing systems are:
a. To ena%$e the the system system to %e designe designedd so that it wi$$ wi$$ meet meet the standard standard or spe"ifi"ation spe"ifi"ation.. &o e"onomi"a$ pipe si'ing s"hedu$e "an %e drawn ena%$e uniform dis"harge from head at the same $e!e$ and "ertain$y not from different $e!e$s. %. To ena%$e ena %$e the system to %e designed to fu$fi$$ the dis"harge out$et reuirements with a minimum minimum of de!i"es# de!i"es# piping and water supp$y from the standpoints standpoints of %oth pressure and !o$ume# thus effe"ting the maximum e"onomy in pump# tan# "ity and or other supp$y "apa"ities. *or *or time sa!i sa!ing ng and and "on! "on!en eniien"e en"e the "a$"u$ "a$"u$ati ations ons start start at the heads heads farthes farthestt from the supp$y supp$y## and pi"in pi"ingg up additi additiona$ ona$ heads heads dis"harge# and thus fina$$y %a" %a " to the point of supp$y. SYNOPSIS OF CALCULATION METHOD$
Spr#%ler or No&&le Orf!e De'a#d in +o +o$ume ( GPM or CMH)
) and in Pressure Pressu re ( PSI or Pa). This is the starting point for ea"h straight,thru or trun "a$"u$ation and for ea"h %ran"h "a$"u$ation# the starting !o$ume %eing determined %y standards or spe"ifi"ation. -fter the first head# the orifi"e pressure is determined %y the "a$"u$ation tota$ of a$$ pressures at the un"tion of the indi!idua$ head with its pipe. *rom this pressure the sprin$er !o$ume is o%tained. (/e$ation %etween 0rifi"e +o +o$ume and 0rifi"e Pressure for Sprin$ers# &o''$es and Hose &o''$es is found in Ta%$e,1- thru 12)
Table-1A
Ta(le)*+
Ta(le )*C
Ta(le , *D
Fr!"o# Pressure De'a#d in PSI (Pa) is the fi"tion $oss in piping %etween the farthest -pressure .se/ 0ead a#d po#" of supply$ -For "0e 1arous ppes2 f""#3s2 1al1es2 e"!2 "0e u#" fri"tion $osses are found in Ta%$e,3)
Ta%$e,3
is the pressure in PSI (Pa) "orresponding to the !erti"a$ distan"e in feet %etween e$e!ation of highest head# and e$e!ation of point of supp$y ( su"h as %ottom of gra!ity tan or %ottom of pump su"tion reser!oir# e$e!ation of point where "ity f$ow test was made# et". ) Stati" Pressure is "a$"u$ated %etween dis"harge heads that are at different $e!e$s# %etween heads and un"tion or referen"e points where pressure adustments must %e made# and %etween heads the $e!e$ of point of supp$y. Stati" Pressure has no re$ation to si'e or $ength of piping. S"a"! - Ele1a"o# / Pressure De'a#d
is the +e$o"ity Pressure in PSI (Pa) "aused %y !e$o"ity of water in pipes. This is so re$ati!e$y insignifi"ant and tedious to figure that it is pra"ti"a$$y a$ways ignored4 it is not to %e "a$"u$ated un$ess spe"ifi"ations reuire it. 4elo!"y Pressure De'a#d
are determined to meet the Tota$ 2emand at a point hori'onta$$y and !erti"a$$y "ommon to %oth Supp$y and 2emand at any time within any 35,hour period of a year. Supply Flo. -GPM / a#d Supply Pressure - PSI /
SUPPLY # Flo. a#d Pressure is eua$
or greater than the Minimum /euired 2emand "onsisting *$ow (Tota$ Heads x /euired GPM per Head) and Tota$ Pressure (0rifi"e# *ri"tion# Stati" and +e$o"ity) In an effort to arri!e at a uniform pra"ti"e in hydrau$i" "a$"u$ations for fire prote"tion systems# a re"ommended standard method and standard forms were introdu"ed in the 1678 re!ision of &*P-,17# ST-&2-/2S *0/ 9-T/ SP/-; S;STMS *0/ *I/ P/0TCTI0&. This standard method em%ra"ed the prin"ip$es and pra"ti"e set up and used %y <-utomati"= Sprin$er Corporation of -meri"a sin"e 16>? and pu%$ished in <-@T0M-TIC= H;2/-@AIC 2-T in &o!. 1655. U#for' Pra!"!e$
This se"tion of <-@T0M-TIC= SP/I&BA/ H;2/-@AIC 2-T- exp$ains and i$$ustrates# %y examp$es# the standardi'ed method as we interpret and pra"ti"e it. *ra"tions of GPM and PSI. In sprin$er %ran"h $ines# tae !o$umes to the nearest ?.1GPM. In a$$ "ross mains# feet mains and supp$y mains# and *ire,*og Systems throughout# tae !o$umes to the nearest GPM# as# 17.5 17 GPM and 17.7 1D GPM. -$$ pressure# fri"tion# orifi"e and stati" are taen to nearest ?.1 PSI. CORRELATION 5ITH NFPA E
17. The fo$$owing out$ine fo$$ows the paragraph headings of Se"tion -3>.3? of &*P-,17# < 9ater Spray Systems=# Fu$y 1678 dition •
C-AC@A-TI0& *0/M. The four forms used are $isted %e$ow and exp$ained in detai$ pages. See examp$e 1 for forms for Tit$e sheet# Hydrau$i" Ca$"u$ation Sheet# Graph Sheet and Summary of Hydrau$i" Ca$"u$ations.
T"le S0ee" is
fi$$ed out of the %eginning of ea"h System "a$"u$ation. It is pro!ided to "onser!e spa"e on the hydrau$i" "a$"u$ation sheet itse$f and to pro!ide re!iewers with a %rief summary of "a$"u$ation method and %asis for design. "ontains a$$ the items of Se"tion -3>.3? of &*P17# %ut the arrangement is a$tered s$ight$y for "on!enien"e in use and "he"ing and to pro!ide a means for more positi!e identifi"ation. The "a$"u$ation B p may %e made on this sheet in $ieu of the graphi"a$ method on Graph Sheet. -s wi$$ %e seen in the examp$e# this form $ends itse$f to pra"ti"a$$y e!ery need Hydraul! Cal!ula"o# S0ee"
the regu$ar & graph sheet used in this# is used for the se!era$ purposes# %oth to sa!e "a$"u$ation time and to pro!ide means for a graphi" summary of demand !s. supp$y. It "an a$so %e used to %a$an"e the !o$ume,pressure of any one $ine# unit or system against that of another. Grap0 S0ee"2
gi!es the re!iewer the essen"e of the entire "a$"u$ation on one sheet# in"$uding minimum and "a$"u$ated demand# and a"tua$ supp$y. Su''ary of Hydraul! Cal!ula"o#s
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I&*0/M-TI& T0 GI+& 0& 2/-9I&G. /efer to the se"tion on I2&TI*IC-TI0& on Tit$e Sheet# whi"h out$ines the pro"edure for identifying heads# un"tion points# %ran"h $ines and units on p$ans and "a$"u$ations. The first entry on the "a$"u$ation sheet shou$d identify the starting point of the "a$"u$ation# and this referen"e point shou$d %e "$ear$y mared on the p$an. Ele1a"o# of the highest
sprin$er or other dis"harge out$et# and e$e!ation re$ation %etween this highest sprin$er or other and e!ery other sprin$er# hose no''$e or other dis"harge out$et# and with re$ation to the point of supp$y# su"h as pump reser!oir %ottom# pump "enter $ine# %ottom of gra!ity tan# or point at whi"h stati" and residua$ pressure were measured on a "ity water f$ow test. These must %e "$ear$y shown on p$an# so that the stati" pressure may "a$"u$ated %etween the water supp$y or supp$ies and e!ery sprin$er# spray no''$e# hose no''$e or other dis"harge out$et. S$ope of roof must %e gi!en so that the stati" differen"e %etween top sprin$er and a$$ other sprin$ers "an %e "omputed. If a$$ heads shown on a drawing are the same ind and si'e# one "o!ering des"ripti!e note may %e used. If a$$ heads expert a minor num%er are the same ind and si'e# the "o!ering note shou$d mae the ne"essary des"ription# adding
Ds!0ar3e C0ara!"ers"!s of Heads .
Instead of indi"ating on the p$ans and hydrau$i" "a$"u$ation sheets a dis"harge "onstant
•
+A0CIT; P/SS@/. In a""ordan"e with the option a$$owed in first paragraph of this Su%se"tion of the Standard# we omit "onsideration of !e$o"ity pressure figures from our "a$"u$ations %e"ause we do not fee$ that the extra wor of this more "omp$i"ated pro"edure is ustified %y the neg$igi%$e differen"e in resu$ts. This is the pra"ti"e genera$$y. *ITTI&GS. Aoss through standard s"rewed fittings# in eui!a$ent feet of stee$ pipe# is taen from Ta%$e E 3# whi"h was made up from *igure 13 of Se"tion -3>.3? of the &*P- E 17 Standard.
<-utomati"= pra"ti"e regarding pressure $oss due to fittings is not stri"t "onforman"e with the standard# %ut we fee$ that it is more "onsistent and as a""urate and our "a$"u$ations are %eing a""epted on this %asis. <-utomati"= s= pra"ti"e is as fo$$ows: 1. The fitting is in"$uded with the pipe on the dis"harge side of the fitting ( that is# the pipe the water is f$owing into )# at the si'e of the out$et. See *ig , 1 for S"rewed *ittings in Stee$ Pipe and *ig , > for *$anged *ittings in Headers and So"et *ittings in @nderground Piping.
3. *ittings Aoss (eui!a$ent feet) is "a$"u$ated where!er there is a "hange in dire"tion of f$ow# ex"epting on$y as fo$$ow: a. The tee or e$$ (in the $ine) into whi"h the sprin$er or no''$e is s"rewed# these fittings $osses ha!ing %een in"$uded in the dis"harge "hara"teristi"s (orifi"e pressure) for the head. See *ig E 3-. %. In the "ase of a no''$e on the end of a swing oint# omit the tee in the $ine into whi"h the swing oint is s"rewed. The e$$s %etween the no''$e and the $ine tee are "a$"u$ated. See *ig ,3%.
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PIP */ICTI0& CH-/T. *igure 11 of &*P-,17 is %ased on the 9i$$iams E Ha'en formu$a at C,13?. *ri"tion Ta%$es E >- thru >G %e$ow are more "on!enient to use. In a""ordan"e with &*P- Standards# fri"tion ta%$es for stee$ pipe are %ased on 9i$$iams, Ha'en C,13?4 for name$ine underground pipe# "ement $ined and as%estos "ement pipe# C,15?# and for un$ined "ast iron pipe C,1??.
FRICTION LOSS IN BLACK STEEL PIPE (SCHEDULE – 40) EXPRESSED IN PSI PER LINEAL FOOT
Table – 3A
FRICTION LOSS IN BLACK STEEL PIPE (SCHEDULE – 40) EXPRESSED IN PSI PER LINEAL FOOT
Table – 3B FRICTION LOSS IN BLACK STEEL PIPE (SCHEDULE – 40) EXPRESSED IN PSI PER LINEAL FOOT
Table – 3C
FRICTION LOSS IN BLACK STEEL PIPE (SCHEDULE – 40) EXPRESSED IN PSI PER LINEAL FOOT
Table – 3D FRICTION LOSS IN BLACK STEEL PIPE (SCHEDULE – 40) EXPRESSED IN PSI PER LINEAL FOOT
Table – 3E
FRICTION LOSS IN BLACK STEEL PIPE-EXPRESSED IN PSI PER LINEAL FT. (SCHED.40 FOR -IN. AND S!ALLER" SCHED.30 FOR #-IN. AND LAR$ER
Table – 3F
FRICTION LOSS IN BLACK STEEL PIPE-EXPRESSED IN PSI PER LINEAL FT. (SCHED.40 FOR -IN. AND S!ALLER" SCHED.30 FOR #-IN. AND LAR$ER
Table – 3$
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S-MPA C-AC@A-TI0&S. In"$uded is a typi"a$ examp$e fo$$owing the prin"ip$es of the Standard# omitting !e$o"ity pressure "onsideration# ex"ept to show the "a$"u$ation pro"esses. The examp$e shou$d %e studied indi!idua$$y as they wi$$ i$$ustrate the genera$ dire"tions fo$$owing.
is fi$$ed out for ea"h indi!idua$ system. 9here there are two or more typi"a$ systems "omp$ete$y indenti"a$ so that no additiona$ "a$"u$ation is reuired# show a sing$e system num%er in the spa"e pro!ided at upper right,hand "orner of sheet# and %eneath it write:
It is of prime importan"e to study "arefu$$y e!ery item in the Tit$e sheet# %e"ause here is determined the ind of system to %e insta$$ed# and the %asis for a$$ "a$"u$ations on su%seuent sheets. -ny error in the %eginning must %e "orre"ted thru out the "a$"u$ations. T"le +lo!% .
a"h spa"e shou$d %e fi$ed in "arefu$$y. -fter <ui$ding and -rea prote"ted#= if %ui$ding or area has a spe"ifi" name or num%er# %e sure to in"$ude it4 if it has not use a des"ripti!e note as to $o"ation# si'e# num%er of stories# o""upan"y# or other identifying data. - # 13.15# 13.3? and referen"es. Che" the type that is the o%e"t of the prote"tion. *or examp$e# where the "om%usti%$e is a materia$ that "an %e extinguished %y the system# "he" xtinguishment# "he" Contro$. If the system is designed to "oo$ euipment su"h as tans to redu"e heat input# "he" xposure Prote"tion. In those "ases where the system is designed to do more than one of those things# "he" those that app$y. Type Pro"e!"o#$
Type sys"e'$ In most "ases the system wi$$ %e automati"# %ut if it is manua$ on$y#
"he" Manua$. If an automati" sprin$er of de$uge system is a""ompanied %y inside and outside hose streams# "he" %oth automati" and manua$. Type 4al1e$ Che"
type of !a$!e used. In manua$$y operated systems# the "ontro$ !a$!e is usua$$y a gate !a$!e# %ut in some "ases it is a de$uge !a$!e whi"h "an %e operated either %y manua$ pu$$ or remote$y. Ds!0ar3e Heads$ eside
the type of head used# write in the si'e or sym%o$ num%er of the heads for the sing$e system "o!ered %y the tit$e sheet# in"$uding hose no''$es. Head Spa!#3$ *i$$ in the data "a$$ed sheet. No"e6 In airp$ane hangars of the fire
for# for the system "o!ered %y the $itt$e resisti!e "onstru"tion# sprin$er spa"ing is extra,ha'ard# %ased on f$oor area# with no $imitation as to the proe"ted spa"ing a$ong the s$oping roof $ine4 for other,than,fire,resisti!e "onstru"tion# sprin$er spa"ing is extra,ha'ard# %ased on f$oor area# %ut proe"ted spa"ing a$ong the roof $ine must not ex"eed ordinary ha'ard. xtra spa"es are pro!ided in this "o$umn so that %oth roof and f$oor spa"ing may %e indi"ated for Hangar o%s# as shown in xamp$e 1.
Des3#ed Co1era3e$
This in"$udes the next D "aptioned items# as fo$$ow
1. De#s"y$ This spa"e is to %e fi$$ed in if there is a spe"ified or standard density for the o""upan"y4 other,wise it may %e $eft %$an. The present trend for determining sprin$er spa"ing and dis"harge rates has %een dire"ted more and more spe"ifi" densities for spe"ifi" ha'ards. 2esign density of different o""upan"y "$assifi"ations is presented in Ta%$e 5. 3. M#'u' GPM7Head$ &*P-,&*@,1> ( and &*P-,&*@,5?6 for <-ir"raft Hangars=) reuire that water de$uge system "a$"u$ations %e made on the %asis on not $ess than an a!erage of 17 GPM per sprin$er# with a maximum !ariation of 17J up or down form this a!erage dis"harge. *or water de$uge systems# write in: 17 GPM E 17J. Some organi'ation reuire a maximum !ariation of 1?J. *or systems where there is a spe"ified density# write in the GPM that wi$$ pro!ide that density on the spa"ing that app$ies to the System "o!ered %y the tit$e sheet. &*P-,&*@,5?6 <-ir"raft Hangars= spe"ifies a density of ?.18 GPM per S*t for foam,water systems. >. M#'u' PSI a" Head$ 9rite in the PSI "orresponding to the dis"harge shown in Minimum GPMHead# a%o!e.
Ta%$e E 5
2esign 2ensity of 2ifferent 0""upan"y C$assifi"ation
5. Nu'(er of Heads Ds!0ar3#3$ Show the num%er of open heads in the system# if on$y a sing$e system is to operate. If two or more systems of open heads are to operate simu$taneous$y# insert in this spa"e#
systems are in!o$!ed# the engineer must "arefu$$y re!iew the situation with respe"t to the water supp$y. D. Hose S"rea's2 GPM$ If the expe"ted demand is a sing$e system p$us one or more sma$$ or $arge hose streams# insert the GPM. If the expe"ted demand is a sing$e system p$us one or more sma$$ or $arge hose streams# insert the GPM for hose stream(s) here. If two or more systems are to operate simu$taneous$y# insert
shou$d %e studied "arefu$$y# as it exp$ains the seuen"e fo$$owed in the "a$"u$ations# the identifying num%er for dis"harge out$et and $etters for un"tions# and the pro"edure for num%ering the "a$"u$ation sheet. P$ease note that the Trun (straight,through) Ca$"u$ations are intended to gi!e an uninterrupted path from the far (or =worst=) head of the system straight to the supp$y point# and this "an genera$$y %e a""omp$ished on a sing$e Sheet 1. If additiona$ sheets are reuired for the straight through "a$"u$ation# they are num%ered 1# 1,-# 1,# et". If one sheet is suffi"ient for straight through# the Graphi"a$ 2emand and Supp$y sheet is 1,-# the Summary is 1,# et". The su%ordinate or <%a$an"ing= ran"h Ca$"u$ations are num%ered 3,>,5,et". y fo$$owing this num%ering p$an and num%ering ea"h system independent$y# it is easy to "a$"u$ate a$$ systems to a un"tion point and to rearrange the sets of sheets if the system first se$e"ted pro!es not to ha!e the maximum demand. T0e lo.er 0alf of "0e T"le S0ee"
Preparatory to mae the "a$"u$ations one wi$$ ha!e made the %asi" $ayout ( see examp$e 1) and wi$$ ha!e re!iewed a$$ systems to note whi"h ones are typi"a$ (a$so whi"h %ran"h $ines# $oops# units# et") so that "a$"u$ation time is sa!ed through re,using "a$"u$ations %y means of referen"e note. 2etermine whi"h system wi$$ pro%a%$y ha!e the greatest demand4 and the sprin$e or no''$e at the end of a %ran"h $ine or $oop# that on a straight,through "a$"u$ation wi$$ produ"e the greatest tota$ pressure (orifi"e L fri"tion L stati") demand. (See xamp$e 1.) HYDRAULIC CALCULATION SHEET$
-fter fi$$ing in the information "a$$ed for at the top of the form and maring it Sheet 1# the first step is to write in the starting point# p$an referen"e point# the of the head# the !o$ume to %e figured from this head and the
The "a$"u$ation pro"eeds dire"t$y through the system from this starting point# "a$"u$ating in the dire"tion opposite to the water f$ow# fo$$owing the path of the water %a" to the supp$y point# pi"ing up the !o$ume for ea"h $ine and unit on the way. This "an near$y a$ways %e performed on Sheet 1. <ran"h= "a$"u$ation are made on separate sheets 3#>#5#et"4 the sheet num%er and starting referen"e for ea"h %ran"h "a$"u$ation are shown in the two right "o$umns of the Trun Ca$"u$ation Sheet 1. -t the un"tion with ea"h su""essi!e unit or system# the !o$ume for the unit or system is added into the Trun Ca$"u$ation4 the added system has $iewise %een "a$"u$ated to this point. Cal!ula"o# Pro!edure$ The
%est way to exp$ain "a$"u$ation pro"edure is %y a "on"rete examp$e. Commen"ing with Pro%$em E 1# refer to the examp$es and their exp$anations and fo$$ow the "a$"u$ations step %y step from the starting dis"harge point to the supp$y point. The same genera$ pro"edure is fo$$owed in *I/,*0G and foam,de$uge "a$"u$ations as in sprin$er "a$"u$ation. 1 was designed for the %eginner. -$$ the e$ements of this simp$e pro%$em are# for "on!enien"e# on one page. Mastery of this pro%$em first wi$$ ena%$e a ui"er and %etter understanding of the more intri"ate phases of the xamp$e Pro%$em# shou$d %e a""omp$ished %efore pro"eeding further. Pro(le' )
Example: Problem - 1
P%&'&le* -- A+ +,e ae /&'+ (,/%&/'+all1 a'2 e%+&all1) +,e a+e% 5l1 5+ 2el&e% +,e %e65&%e2 $P! 2&,a%7e a+ e65al /% 7%a+e% +,a' +,e 2ea'2 %e5%e. P%/ble* -- A e&al ,aa%2 %e65&%e 8"000 S6F+ /9 9l//% (:0; < =0;) +/ be 2el57e2 a 9/ll/* a.) !&'&5 2e'&+1" 0.30 $P!>S6F+ /9 9l//%. b.) Te' ?@ +a'2a%2 %&'le% 80;CC" b%a', l&'e 80;CC 800 S6F+>S. .) 800 S6F+>S < 0.30 $P!>S6F+ &'&5 30 $P!>S (Table =) 2.) &+, 30 $P!>S6F+ +,e %&'le% /%&9&e %e5%e & :#. PSI (Table -8C) e.) A =0"000 7all/' 7%a&+1 +a' +/ be 8"=00; aa1 9%/ 2el57e ale. 9.) F&'2 +,e ,e&7,+ (,) (9%/ 7%a2e +/ b/++/ /9 7%a&+1 +a') %e65&%e2 +/ 5l1 +,e 2el57e 1+e 2ea'2.
Ta%$e , 7
SUMMARY OF E8AMPLE PRO+LEM
PSI
Head Spr#%ler orf!e pressure
9:$;
Fr!"o# loss # pp#3
*<$*
Ele1a"o# -s"a"!/ pressure
:$;
TOTAL DEMAND AT GRADE)TANK RISER
=>$=
RE?UIRED SUPPLY TANK 0 @ *9>$=
=>$=
