W e d n e s d a y , J u l y 7 , 2 0 1 0

Water Pipes Sizing

Mechanical Systems Pipe Sizing Mechanical Engineer Task WaterPipe Sizing

DRAFT

1. Introduction: MEP Systems & Water Pipes2. Fundamentals: Water Properties & Pipe Flow Basics3. HVAC Systems: Water Pipe Sizing4. Water Supply Systems: Pipe Sizing5. Drainage Systems: Pipe Sizing6. Fire Protection Systems: Water Pipe Sizing7. Facility System: Water Pipes Sizing8. Other Piping Systems9. References

Pipe Flow Application

i. Pump Assisted Flow: Mechanical Equipments (Pumps )

ii. Gravity Flow: Gravity Pump Flow Pressurized Flow GravityFlow Pressurized Flow (or) No-PressureFlow

1.B. Pressurized Flow in Mechanical Systems Pressurized Flow

i. One-Way Flow : Pump

1. Introduction: MEP Systems & Water Pipes1.A. Pipe Flow Application

Assisted Pressure (or) Gravity Pressure ii. Loop Flow (Circulation) : Open Loop (or)

Closed Loop, 100% Loop (or) Partial Loop PumpAssisted Pressure

Pressurized Flow Systems i. HVAC System: Chilled Water, Condenser Water, Hydronic Systems, etc.

ii. Domestic Water Supply System: Cold water supply, Hot water supply,etc.

iii. Sanitary Drainage & Sewerage: Ejector Pump Discharge Pipesiv. Industrial Utilities (Water): Process Water, Process Cooling water,

Deionized (DI) Water, Ultra Pure Water, etc.v. Water Based Fire Protection Systems: Sprinkler System, Standpipe (or)

Rising Mains & Hose-reel Systems, Fire Hydrants, etc.

1.C. No-Pressure Gravity Flow Drainage System No-pressuresystem Flow Pressure Impact Force Pipe, Fitting & Pipe Support Systems Pressure Pressure Vertical Flow Gradient Flow Drainage System Siphon Anti-siphonage System Storm Water Discharge System Siphon Siphonage System No-Pressure Gravity Flow

i. HVAC: Condensate Drainageii. Sanitary Plumbing: Drainage & Sewerage Systems (Foul Water)iii. Rain Water (Storm Water) & Surface Drainage : Conventional (or)

Siphoniciv. Other Drainage Systems

2. Fundamentals: Water Properties & Pipe Flow Basics2.A. Water Properties

Water Properties Standard Condition Value

DensityS.I : 1.0 kg/liter ( 1,000 kg/m )I.P: 8.34 lbm/us-gal (62.42 lbm/ft)

PressureStandard Atmospheric pressure (atm) 1 atm = 14.696 psia = 101,325 Pa = 33.91 ft of water= 10.33 m H2O

Thermal PropertiesI.P (USCS) UnitsSpecific Heat Capacity (Cp): 1 BTU/#.FLatent Heat of Fusion (water-to-ice) at 32F : 144 BTU/#Latent Heat of Vaporization (water-to-vapor) at 212F : 970 BTU/#Latent Heat of Vaporization (water-to-vapor) at 95F : 1,040 BTU/# Formula RT = gpm x T / 24

gpm (gal/min) x T (F)x 60 (min/h) x 8.34 (#/gal) x 1 (BTU/#.F)= 500 x gpm x T (BTU/h)

S.I UnitsSpecific Heat Capacity (Cp): 4.187 kJ/kg.K [ 1 kcal/kg.C ]Latent Heat of Fusion (water-to-ice) at 0C : 334 kJ/kg Latent Heat of Vaporization (water-to-vapor) at 100C : 2,256kJ/kg Latent Heat of Vaporization (water-to-vapor) at 35C : 2,420 kJ/kg

2.B. Pipe Material / Standard Pipe Material Application PipeMaterial

Internal Pressure ( Fluid )External Loads from Backfill & Traffic ( )Internal Smoothness ( )Corrosion Resistance ( )Chemical Inertness ( Fluid )No Pollution: Fluid Pollution Methods of Joints ( )

Cost ()Other Factors ( )

Pipe Material i. Copper/Brass, Steel (Black Steel, Galvanized Steel,

Stainless Steel, etc.), Cast-Iron, Ductile Iron, etc. ii. PVC, ABS, PPR, PVDF, etc.iii. Vitrified Clay ( ) , Concrete (

) , etc.iv. Fluid Lining

(e.g. PVDF Lined steel pipe, Concrete-lined Ductile IronPipe, etc.)

Standard U.S (ASTM, API), UK (B.S), Japan (JIS), Australia (AU), Singapore(SS). Standard Cross-Reference Standard Pressure Class / Type Steel Pipes (Schedule10, 20, 30, 40, 80, XS, ST); Copper Pipes (Type K, L, M in ASTM, Type X, Y, Z inB.S)

2.C. Pipe Sizing ConsiderationsPressurized (including Gravity Pressure) Flow Mechanical Systems

i. Sufficient Pressure & Flowrate: ()

ii. Limit Pressure Loss : iii. Limit Flow Speed (Velocity) :

Pipe Sizing Piping System () Appliances Flowrate Pressure Design Pressure Pump Energy Consumption Pressure Loss (Corrosion ) Noise & Vibration Flow Velocity Pipe Sizing

i. Pipe Material & Standardii. Required Flowrateiii. Allowable Friction Lossiv. Allowable Flow Velocity

i. Using Pipe Friction Charts

ii. By Calculations

System

2.D. Basic Calculations i. Pipe Area (A)

Pipe Area A= 0.25 x x d

d Internal Diameter Pipe Standard

ii. Area (A), Flowrate (Q) and Velocity (V) RelationshipBasic Unit Flowrate = Area x Velocity (or) Q= A x V Unit

I.P (USCS) Units

Q = 2.45 x d x V where Q (US gpm), d (in) and V (ft/s)..[ 0.25 x x d (in) x V (ft/s) x { 60 (s/min)} x { 12 (in/ft) } x { (1 / 231)(U.S gal / in)} ]

S.I Units

Q = 0.0471 x d x Vwhere Q (l/min), d (mm) and V (m/s)...[ 0.25 x x d (mm) x V (m/s) x { 60 (s/min)} x { (1/1000) (m/mm)} x {1,000 (l/m)} ]

iii. Pipe Frictions Pipe Friction Charts Calculation Formula Pipe Friction

Chart Calculation Formula Darcy-Weisbach Equation Iterative ( ) Fluid Dynamic Properties Viscousity,Reynold Number, Friction Factors Sprinkler Systems Water Distribution IrrigationSystems Hazen-Williams equation Darcy-WeisbachEquation

iv. Total Pressure Loss

Total Pressure Loss = Static Pressure Loss + Total Friction Loss +Velocity Pressure

Total Friction Loss = Pipe Friction Loss + Fitting Pressure Loss

Fitting Pressure Loss

i. Method 1: Equivalent Pipe Length (or)ii. Method 2: Dynamic Loss Factor (K) P= K x [ V / (2 g) ]

Friction Loss Circuit Loss Series R = R1 + R2 + R3 + Parallel R = 1 / [ (1/R1) + (1/R2) + (1/R3) + ] Pressure Loss Path Series

v. Pipe Weight per Unit Length (for Pipe Support) Pipe Standard Water Weight and Pipe Weight ( Water Weight = Volume x Density) HVAC Piping Insulation 2 Insulation 2.5 weight/unit length

Confirm ( )

( I.P (USCS) Units)

W = 0.3404 x d where W (lbm/ft) and d (in)...[0.25 x x d (in) x { 1/144 (ft/in) } x 1 (ft/ft) x { 62.42 (lbm / ft)}]

( S.I Units)

W = d / 1,273where W (kg/m) and d (mm)...[0.25 x x d (mm) x { (1/1000) (m/mm)} x 1 (m/m) { 1,000 (kg/m)}]

Catalogue Carbon Steel Pipe Specific Gravity 7.85 ( . ) [ Eqn: x dmean x t x Water Density x 7.85 ]

3. HVAC Systems: Water Pipe Sizing3.A. Flowrate

Chilled Water Piping Flowrate

i. Chilled Water Flowrate: 2.4 gpm/tonii. Condenser Water Flowrate: 3.0 gpm/ton

3.785 litre/us gal Liter/min.USRT ARI 550 Condition Standard Centrifugal Chiller Configuration Chilled Water T: 10F (5.6C) RT = gpm x T / 24Chilled Water Design T T: 15F 2.4 x (10 / 15) = 1.6 gpm Chiller Performance Chilled Water T ( Air Side Equipments Water Coil )Condenser Water Flowrate Vapor Compression Cycle Chiller

3.0 gpm/ton Condenser ARI 550 (Tips: It is related to COP.)Open Evaporative Cooling Tower 94 F T: 10F CoolingTower 10F x 1 (BTU/#.F) / 1,040 (BTU/#) 1% Sensible Cooling EvaporationLoss 0.8% Cooling Tower Drift Loss 0.1% Chemical Concentration 1.5% of Circulation Flow 3 gpm x 1.5% = 0.045 gpm/RT

In Summary:Chilled Water: gpm = 24 x RT / TCondenser Water: gpm = 3 x RT (for chiller with vaporcompression cycle)Cooling Tower Makeup: gpm = 0.05 x RTCondensate: gpm calculate from dehumidifying process

3.B. Flow Velocity & Pressure Loss (Corrosion ) Noise & Vibration Flow Velocity Flow Velocities Reference Recommended Maximum Velocities for Closed (Pressurized) Systems.

ServiceVelocity Range

S.I (m/s) I.P (fps)Pump Discharge 2.4 to 3 8 to 12Pump Suction 1.2 to 2 4 to 7Drain Line 1.2 to 2 4 to 7Header 1.2 to 4.5 4 to 15Riser 1 to 3 3 to 10General Service 1 to 3 5 to 10City Water 1 to 2 3 to 7

Recommended Maximum Velocities to prevent Erosion [ ]

Normal AnnualOperating Hours

Maximum Recommended Water Velocity

I.P (fps) S.I (m/s)1,500 12 3.62,000 11.5 3.5

3,000 11 3.34,000 10 35,000 9 2.78,000 8 2.4

3.C. Quick Pipe Sizing Black Steel Pipe Condenser Water BlackSteel Pipe Galvanized Recommended Sizing Criteria

Service P*Velocity

(m/s) ( ft/s )Chilled Water < 40 < 2.4 < 8.0Condenser Water < 50 < 2 < 6.6

P* - (mm Aq/m) or (ft.wg/1000 ft)Velocity Recommended MaximumVelocities Criteria Justify Recommended Sizing Criteria: Velocity Velocity Friction Loss (and PumpPower) Energy Efficient Chilled Water Total Closed Loop Condenser Water ChemicalConcentration Corrosion FlowVelocity Condenser Water Pipe Friction Loss Factor Chilled Water Pipe

Chilled-Water Pipe Sizes

Pipe SizePipeSch.

InternalDiameter

SI Units IP (USCS)(USRT)

@T=10F

Flowrate Vel. P Flowrate Vel. P

( in) (mm) ( in) ( l/min)(

m/s)(

mm/m) ( gpm)(

ft/s) (ft/100')

3/4" 20 40 0.824 15 0.7 40 4 2.4 4.0 1.71" 25 40 1.049 27 0.8 40 7 2.6 4.0 2.91-

1/4" 32 40 1.38 56 1.0 40 15 3.2 4.0 6.3

1-1/2" 40 40 1.61 84 1.1 40 22 3.5 4.0 9.2

2" 50 40 2.067 160 1.2 40 42 4.0 4.0 17.52-

1/2" 65 40 2.469 260 1.4 40 69 4.6 4.0 28.8

3" 80 40 3.068 460 1.6 40 120 5.2 4.0 503-

1/2" 90 40 3.548 675 1.8 40 180 5.8 4.0 75

4" 100 40 4.026 940 1.9 40 250 6.3 4.0 1045" 125 40 5.047 1,700 2.2 40 450 7.2 4.0 1886" 150 40 6.065 2,700 2.4 38 710 7.9 3.8 2968" 200 30 8.071 4,800 2.4 28 1,260 7.9 2.8 525

10" 250 30 10.136 7,590 2.4 21 2,000 7.9 2.1 83312" 300 30 12.09 10,800 2.4 17 2,850 8.0 1.7 1,18814" 350 30 13.25 12,970 2.4 15 3,420 8.0 1.5 1,42516" 400 30 15.25 17,180 2.4 13 4,540 8.0 1.3 1,89218" 450 ST 17.25 22,000 2.4 11 5,800 8.0 1.1 2,41720" 500 ST 19.25 27,370 2.4 10 7,230 8.0 1.0 3,01322" 550 ST 21.25 33,360 2.4 9 8,800 8.0 0.9 3,66724" 600 ST 23.25 40,000 2.4 8 10,550 8.0 0.8 4,396

Condenser-Water Pipe Sizes

Pipe SizePipeSch.

InternalDiameter

SI Units IP (USCS)(USRT)

@*STD

Flowrate Vel. P Flowrate Vel. P

( in) (mm) ( in) ( l/min)(

m/s)(

mm/m) ( gpm)(

ft/s) (ft/100')

3/4" 20 40 0.824 16 0.8 50 4 2.5 5.0 1.41" 25 40 1.049 30 0.9 50 8 2.9 5.0 2.61-

1/4" 32 40 1.38 63 1.1 50 17 3.6 5.0 5.5

1-1/2" 40 40 1.61 95 1.2 50 25 4.0 5.0 8.4

2" 50 40 2.067 180 1.4 50 48 4.5 5.0 15.92-

1/2" 65 40 2.469 290 1.6 50 77 5.1 5.0 25.5

3" 80 40 3.068 520 1.8 50 137 6.0 5.0 45.83-

1/2" 90 40 3.548 760 2.0 50 201 6.5 5.0 66.9

4" 100 40 4.026 980 2.0 43 259 6.5 4.3 86.35" 125 40 5.047 1,550 2.0 33 410 6.5 3.3 1376" 150 40 6.065 2,230 2.0 27 589 6.5 2.7 1968" 200 30 8.071 3,960 2.0 19 1,046 6.5 1.9 349

10" 250 30 10.136 6,250 2.0 15 1,651 6.5 1.5 55012" 300 30 12.09 8,880 2.0 12 2,346 6.6 1.2 78214" 350 30 13.25 10,675 2.0 11 2,820 6.6 1.1 94016" 400 30 15.25 14,140 2.0 9 3,736 6.6 0.9 1,24518" 450 ST 17.25 18,100 2.0 8 4,782 6.6 0.8 1,59420" 500 ST 19.25 22,500 2.0 7 5,945 6.5 0.7 1,98222" 550 ST 21.25 27,450 2.0 6 7,252 6.6 0.6 2,41724" 600 ST 23.25 32,860 2.0 6 8,682 6.6 0.6 2,894

*STD: USRT for Chiller with Vapor Compression Cycle at ARI:550 StandardCondition

4. Water Supply Systems: Pipe SizingRefer To -http://chawlwin.blogspot.com/2008/11/domesticwater01.html

Loading Units (Fixture Units) and Flowrate

Flow Velocity

Hot-Water Circulation Capacity (to maintain temperature, calculate heat loss)

5. Drainage Systems: Pipe Sizing

Refer Tohttp://chawlwin.blogspot.com/2008/10/sanitary01.html

Discharge Units (Drainage Fixture Units) and Flowrate

Flow Velocity, Vertical & Gradient Flow

6. Fire Protection Systems: Water Pipe SizingFlow rate required

Ko Chaw - at 3:36 AM

Prescriptive Pipe Sizes & Sized by Hydraulic Calculation

7. Facility System: Water Pipes SizingFlowrate and Equipment Utility Matrix

Flow Velocity

8. Other Piping Systems

9. References

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