Basic Hydraulics for Fire Sprinkler Systems DISCLAIME R 6/13/16. Alliance Fire Protection North Kansas City, MO. Presented by Matt Grisé

Transcription

1 Basic Hydraulics for Fire Sprinkler Systems Presented by Matt Grisé 1 2 DISCLAIME R This webi nar and its content is not a formal inte rpre tatio n issued purs ua nt to NF PA re g ulatio ns. Any opinio nexpressed is the perso nal opinion ofthe autho r and prese nte r and does not necessarily present the official position of the NF PA and its Technical Co mmitte e s. Basic Hydraulics for Fire Sprinkler Systems AFSA would like to thank the following company for their generous support of this webinar: Alliance Fire Protection North Kansas City, MO [Alliance Fire Protection Logo] 3 1

2 Basic Hydraulics for Fire Sprinkler Systems Matt Grisé Alliance Fire Protection 130 w 9th Ave. North Kansas City, MO Matt is a Jayhawk mechanical engineer out of the University of Kansas specializing in fluid power systems. He is a professional engineer registered in Kansas and Missouri with 8 years of fire sprinkler design experience in addition to numerous summers spent in the field and fab shop. Matt is additionally certified as an Advanced Designer through AFSA, NICET level 2 in Water Based Systems Layout, and a LEED accredited professional. He has served six years on the executive board of the MO-KAN chapter of the Society of Fire Protection Engineers including two years as president. He directs training programs at Alliance Fire Protection of Kansas City. 4 What are we dealing with? What is actually happening? Heat activated ONLY!!! Typically only 1-5 heads go off Remote area is 2 to 3 times the number of heads that go off 5 One fire at a time per system What Do We Need? 6 Water Supply Building Piping Underground Piping 2

3 What Affects Water Movement? 7 Energy Friction What is Energy?? 8 Height Pressure Speed Velocity Head Calculated Demand> Actual Demand Energy Height Net Change YourTown Water Tower 9 1foot =.433psi Only the difference between the test hydrant and the sprinkler head 3

4 Energy Pressure the big deal K factor relates to opening size larger K = larger orifice less pressure for more water. Q = K P 10 Water Source City Supply Storage Tank Pond/Well/River Fire Pump Energy from motor is transferred to the water as pressure What is Friction? Opposes movement Water sticks to things it touches also sticks to itself Calculate Friction with Hazen-Williams formula Pf = 4.52 * (GPM)^1.85 (C)^1.85 * (d)^ C = Constant (depends on material) d = actual internal pipe diameter (inches) 12 Darcy Weisbach Method for Antifreeze Systems over 40 gallons (more accurate) f ρ* (GPM)^2 Pf = (d)^5 Just get this from the Moody Diagram! Roughness E factor from NFPA 13 Annex Kinematic Viscosity (based on liquid and temperature) Re = 4vA v P 4

5 Friction Effects: Pipe Diameter has the most prominent effect 13 C factor and flow (gpm) are next Pipe length is important too For Example: Same Material-Same GPM 4 pipe 2 pipe 2 pipe 1 pipe 2 pipe has 25 times the friction!! 1 pipe has 27 times the friction!! Friction Effects: Pipe Diameter has the most prominent effect 14 C factor and Flow gpm are next (2x length = 2x friction) Pipe Length is important too For Example: Same Material-Same Pipe Size Same Flow-Same Pipe Size Change Materials Double the flow 3.6 times the friction!! CPVC- C=150 Dry Steel C = 100 More than double the friction!! (2.11x) Friction Effects: Don t forget fittings: 15 Equivalent length determined by testing or formula approximation. (NFPA 13 lists equivalent lengths and formulas) x 10-0 (for 2 s-40 pipe) 5

6 16 Polling Question How many people are listening/viewing today s presentation from your computer site? Questions? 17 Questions will be answered in the order they are received. If we do not get to your question, we apologize in advance. Your question will be answered by after the program. Formula Sheet Flow gpm Q 18 Pressure psi P K-factor gpm/ psi K Q = K P K = Q/ P P = (Q/K)^2 6

7 Basic Remote Area: ft Number of heads on one line = 1.2 x sqrt of operating area distance between heads 10 ft 1.2 x sqrt of 1500 sqft / 10 ft between heads = 4.6 heads, RU = 5 heads Number of heads in total = Operating area sqft / sqft per head 1500 sqft / 120 sqft per head = 12.5 heads, RU = 13 heads The Calc Process: (starts at the first head) For Example: A standard spray head K = 5.6 Ordinary group 1 density (.15 gpm/sf) Covering 130 sf Dry pipe steel system (C= 100) 20 Q = 130 sf x.15 gpm/sf = 19.5gpm (for the first head) P = (19.5/5.6)^2 = 12.13psi (pressure required to get 19.5 gpm ou t of the h ead) Must be at least 7psi The Calc Process: (for a tree system) Start from the end and add it up! 21 This head sees the extra pressure and overdischarges more This head sees the extra pressure and over-discharges Creates Friction Loss in the pipe Minimum Flow from the most demanding head Combined Flow creates even more pressure loss Pressure must be higher here to make it up 7

8 Schedule 40 Dry (C=100) The Process A #4 #3 # #1 K=5.6 1 to 2 K = eq K=5.6 K=5.6 K=5.6 4 to A 3 to 4 2 to 3 A Pf = 1x T From Hazen- Williams Form u l a * (19.5)^ P =(Q/K)^2 Q = K P K = Q/ (P) Keq = 18.7 (100)^1.85 * (1.049)^ The Process So to the end of the line: 23 A total required Flow (Q) and Pressure (P) for the line Q = Keq P Allows for each line to be like a single (giant) sprinkler head The Process Back to the test hydrant: System demand: (for example) psi Different Material Different Diameter (Sch 40 to Sch10) Different Diameter (pipe size) 24 Any time a Hazen-Williams Variable Changes you have to re-start the equation P = Ft 4.52 * (GPM)^1.85 (C)^1.85 * (d)^4.87 8

9 The Flow Chart Above this line: not enough pressure System Demand 25 Flow Test: Static 70 psi Residual psi Flow 700 gpm Excess Pressure (safety) The Process: Hand calculations 26 ok, but The Hardy Cross Method for grid systems Time to Use a computer! Computer Calcs: Don t Forget 27 GREAT COMPUTER PROGRAM 9

10 Computer Calcs: Pipe diameter? K Factor? 28 Di scharge amount? C Factor? Fi tti n gs? Pipe Length? Check the inputs!! 29 Different Format Same information is all here 30 Increasing Flow Path flow volume increases at each calc node Direct Flow Path flow volume may go up or down at each node 10

11 Things to Watch: 31 Small pipe on lines, mains and risers. K factor does not include drop or sprig. Change in materials w/o change in C factor. Very long pipes and/or few fittings. Remote area not long enough, 1.2xsqrt area. Calculates thin-wall, uses S 40. Doesn t include 30% increase for dry. Doesn t include 30% increase for >2:12 slope. Elevation included only to F.F. not to source. Flow switches 2 or less in size Supply pressure under 20 psi Basic Hydraulics for Fire Sprinkler Systems Final Questions? Questions will be answered in the order they are received. If we do not get to your question, we apologize in advance. Your question will be answered by after the program. 32 Basic Hydraulics for Fire Sprinkler Systems Please contact Matt Grisé if you have any questions regarding the content in today s presentation. Matt Grisé Allliance Fire Protection 130 w 9th Ave., North Kansas City, MO (913) MG@afpsprink.com 33 11

12 Basic Hydraulics for Fire Sprinkler Systems Thank You North Kansas City, MO 34 Basic Hydraulics for Fire Sprinkler Systems Instructions Receive Certificate of CE Credit To rec eiv e CEUs for today s program, you must hav e registered online for the liv e webinar, then complete an evaluation form after the program. To complete the evaluation go to: Certificateswill go out within 2 weeks. Thank you! 35 12