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VALVESIZING

REFERENCEGUIDE

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TABLE OF CONTENTSIntroduction ....................................................................................................................................... 4Valve Flow Terminology......................................................................................................................... 4The Sizing Process................................................................................................................................ 5

Operating Conditions ................................................................................................................. 5Fluid Properties.......................................................................................................................... 5Rangeability ............................................................................................................................... 5Cv and Flow Sizing Formulas ..................................................................................................... 6

CV Formulas for Liquid FlowCV Formulas for Vapor FlowCV Formulas for Two Phase Flow

Flow Velocity Formulas .............................................................................................................. 7Flow Velocity for Liquid FlowFlow Velocity for Vapor Flow

Nomenclature............................................................................................................................. 8Conversion to Cg and Cs ........................................................................................................... 9

Seat Leakage ..................................................................................................................................... 12Actuator Sizing .................................................................................................................................... 12

P Tables................................................................................................................................. 13Actuator Air Volume ................................................................................................................. 26

Application Guide for Cavitation, Flashing and Compressible Flow Services ....................................... 27Liquid Flow ..................................................................................................................................... 27

Cavitation ................................................................................................................................. 27Cavitation DefinitionCavitation CountermeasuresApplication of Norriseal 2700A Trims in Cavitation Service........................................... 28

Cavitation AvoidanceCavitation TolerantCavitation ContainmentCavitation Prevention

Application Summary.................................................................................................... 28The Cavitation Phenomena .......................................................................................... 29

Fluid and Pressure ProfilesChoked Flow and Incipient CavitationCavitation Damage

Flashing .......................................................................................................................... 30Flashing DefinitionFlashing Countermeasures

Body MaterialTrim Selection

Application of Norriseal 2700A Valves in Flashing Service ........................................... 31Body MaterialTrim Selection

The Flashing Phenomena............................................................................................. 31Liquid Flow Velocity - Body Material......................................................................................... 31

Compressible Flow Noise .................................................................................................................... 32Compressible Flow Noise DiscussionCompressible Flow Noise CountermeasuresApplication of Norriseal 2700A Trims in Compressible Flow Applications................................. 32

Standard TrimsDB I and DB II Multiple Orifice TrimsCompressible Flow Velocity Limits



Two Stage Trims and Backpressure OrificesThe Compressible Flow Noise Phenomena.............................................................................. 33

TABLESTable 1-Trim Rangeability...................................................................................................................... 6Table 2-Cg & Cs Conversion Factors .................................................................................................... 9Table 3-Fluid Properties ...................................................................................................................... 10Table 4-FL Factors ............................................................................................................................... 11Table 5-Flanged Body Inlet and Outlet Diameters ............................................................................... 12Table 6-Allowable Seat Leakage Classes............................................................................................ 12Table 7-Allowable P Ratings 2700A/E Cage Control Trim, Teflon Packing 9 Actuator....................... 14Table 8-Allowable P Ratings 2700A/E Cage Control Trim, Teflon Packing 12 Actuator..................... 15Table 9-Allowable P Ratings 2700A/E Cage Control Trim, Teflon Packing 16 Actuator..................... 16Table 10-Allowable P Ratings 2700A/E Cage Control Trim, Teflon Packing 18 Actuator................... 17Table 11-Allowable P Ratings 2700A/E Cage Control Trim, Grafoil Packing 9 Actuator .................... 18Table 12-Allowable P Ratings 2700A/E Cage Control Trim, Grafoil Packing 12 Actuator .................. 19Table 13-Allowable P Ratings 2700A/E Cage Control Trim, Grafoil Packing 16 Actuator .................. 20Table 14-Allowable P Ratings 2700A/E Cage Control Trim, Grafoil Packing 18 Actuator .................. 21Table 15-Allowable P Ratings 2700A/E Plug Control Trim, 12, 16 & 18 Actuators............................. 22Table 16-Allowable P Ratings for Unbalanced Trim, No.9 Actuator ................................................... 23Table 17-Allowable P Ratings for Unbalanced Trim, No.12 Actuator ................................................. 24Table 18Allowable P Ratings for Unbalanced Trim, No.16 Actuator .................................................. 25Table 19-Actuator Air Chamber Volume & Required Added Air to Actuate .......................................... 26Table 20-Liquid Flow Velocity Limits.................................................................................................... 31Table 21-Flow Coefficients, CV, for 2200/2220 Unbalanced Modified Percent. Plug Control................ 35Table 22-Flow Coefficients, CV, for 2275A Unbalanced Modified Percentage Plug Control ................. 35Table 23-Flow Coefficients, CV, for 2400/2420 Unbalanced Modified Percent. Plug Control................ 36Table 24-Flow Coefficients, CV, for 2700A/E Balanced Quick Opening Cage Control.......................... 36Table 25-Flow Coefficients, CV, for 2700A/E Balanced Linear Cage Control ....................................... 37Table 26-Flow Coefficients, CV, for 2700A/E Balanced Equal Percentage Cage Control ..................... 37Table 27-Flow Coefficients, CV, for 2700A/E Balanced DB I Cage Control .......................................... 38Table 28-Flow Coefficients, CV, for 2700A/E Balanced DB II Control................................................... 38Table 29-Flow Coefficients, CV, for 2700A/E Balanced CAV II Cage Control....................................... 39Table 30-Flow Coefficients, CV, for 2700A/E Balanced Modified Percentage Plug Control .................. 39Table 31-Flow Coefficients, CV, for 2700A/E Balanced Quick Opening Plug Control ........................... 40Table 32-Flow Coefficients, CV, for 2700A/E Unbalanced Modified Percent Plug Control.................... 40

FIGURESGraph 1-Pressure Drop Profile ............................................................................................................ 41Graph 2-Liquid Flow Relationship with Pressure Drop ......................................................................... 42Graph 3-CAV II Flow Noise Attenuation............................................................................................... 42Graph 4-Pressure Profiles, Single Stage and Three stage Trims ........................................................ 43Graph 5-DB I & DB II Flow Noise Attenuation...................................................................................... 43



INTRODUCTION

A Control Valve performs a special task, controlling the flow of fluids so a process

variable such as fluid pressure, fluid level,

flow rate or temperature P

QCV

where

can be controlled. In addition to controlling the flow, a control valve may be used to shut off flow. A control valve may be defined as a valve with a powered actuator that responds to an external signal. The signal usually comes from a controller. The controller and valve together form a basic control loop. The control valve is seldom full open or closed but in an intermediate position controlling the flow of fluid through the valve. In this dynamic service condition, the valve must withstand the erosive effects of the flowing fluid while maintaining an accurate position to maintain the process variable.

A Control Valve will perform these tasks satisfactorily if it is sized correctly for the flowing and shut-off conditions. The valve sizing process determines the required CV, the required FL, Flow Velocities, Flow Noise and the appropriate Actuator Size

VALVE FLOW TERMINOLOGY

CV: The Flow Coefficient, CV, is a dimensionless value that relates to a valve’s flow capacity. Its most basic form is

Q=Flow rate and P=pressure drop across the valve. See pages 5 and 6 for the equations for liquid, gas, steam and two-phase flow. The CV value increases if the flow rate increases or if the P decreases. A sizing application will have a Required CV

while a valve will have a Rated CV. The valve’s rated CV must equal or exceed the required CV.

FL: The FL, Liquid Pressure Recovery Coefficient, is a dimensionless constant used to calculate the pressure drop when the valve’s liquid flow is choked. Increasing the pressure drop when the flow is choked will not increase the flow rate. The FL is the square root of the ratio of valve pressure drop to the pressure drop from the inlet pressure to the pressure of the vena contracta. See page 5 for the FL equation. The FL factor is an indication of the valve’s vena contracta pressure relative to the outlet pressure. See Graph 1. If the FL

were 1.0, the vena contracta pressure would be the same as the valve’s outlet pressure and there would be no pressure recovery.

As the FL value becomes smaller the vena contracta pressure becomes increasingly lower than the valve’s outlet pressure and the valve is more likely to cavitate. A valve’s Rated FL varies with the valve and trim style, it may vary from .99 for a special multiple stage trim to .60 for a ball valve.

Rated FL: The Rated FL is the actual FL

value for a particular valve and trim style.

Required FL: The Required FL is the FL

value calculated for a particular service condition. It indicates the required FL

needed to avoid choked flow. If the Rated FL is less than the Required FL, the liquid flow will be choked with cavitation.

Vena Contracta: The vena contracta is where the jet of flowing fluid is the smallest immediately downstream of the trim's throttle point. At the vena contracta, the fluid's velocity is the highest and the fluid's pressure is the lowest.

Vapor Pressure: A fluid's vapor pressure is the pressure where the fluid will change from a liquid to a vapor. The liquid will change to a vapor below the vapor pressure and a vapor will change to a liquid above the vapor pressure. The vapor pressure increases as the temperature increases.



Choked Flow: Liquid flow will become choked when the trim's vena contracta is filled with vapor from cavitation or flashing. Vapor flow also will become choked when the flow velocity at the vena contracta reaches sonic. A choked flow rate is limited, a further decrease of the outlet pressure does not increase flow. Choked flow is also called critical flow.

Cavitation: Cavitation is a two stage liquid flow phenomena. The first stage is the formation of vapor bubbles in the liquid as the fluid passes through the trim and the pressure is reduced below the fluid's vapor pressure. The second stage is the collapse of the vapor bubbles back to a liquid as the fluid passes the vena contracta and the pressure recovers and increases above the vapor pressure. The collapsing bubbles are very destructive when they contact metal parts and the bubble collapse may produce high noise levels.

Flashing: Flashing is similar to cavitation except the vapor bubbles do not collapse, as the downstream pressure remains less than the vapor pressure. The flow will remain a mixture of vapor and liquid.

Laminar Flow: Most fluid flow is turbulent. However, when the liquid flow velocity is very slow or the fluid is very viscous or both, the flow may become laminar. When the flow becomes laminar, the required CV

is larger than for turbulent flow with similar conditions. The ISA sizing formulas adjust the CV when laminar flow exists.

THE SIZING PROCESS

The first sizing step is to determine the required CV value for the application. Next determine if there are unusual conditions that may affect valve selection such as cavitation, flashing, high flow velocities or high flow noise. The valve sizing process will determine the proper valve size, valve trim size , valve trim style and actuator size. Norriseal’s Valve Sizing Program will

accurately calculate the CV, flow velocity and flow noise. The program will also show messages when unusual conditions occur such as cavitation, flashing, high velocity or high noise. The results from Norriseal’s Valve Sizing Program are only one element of the valve selection process. Knowledge and judgment are also required. This manual will give the user some of the sizing basics.

The liquid, gas and steam CV calculation methods, in this manual, are in accordance with ISA 75.01 and the gas and steam flow noise calculations are in accordance with ISA 75.07.01. These two ISA Standards are in agreement with IEC-534. These standards have worldwide acceptance as the state of the art in CV and Flow Noise determination.

OPERATING CONDITIONS

The most important part of Valve Sizing is obtaining the correct flowing conditions. If they are incorrect or incomplete, the sizing process will be faulty. There are two common problems. First is having very conservative conditions that overstate the CV and provide a valve less than ½ open at maximum required flow. The second is stating only the maximum flow condition that has minimum pressure drops and not stating the minimum flow conditions with high pressure drops that often induce cavitation or have very high rangeability requirements.

Fluid PropertiesTable 3 lists many fluid properties needed for valve sizing. These fluid properties are in Norriseal’s Valve Sizing Program’s database and do not need manual entry.

Rangeability: Rangeability is the ratio of maximum to minimum controllable CV. This is also sometimes called CV Ratio or Turndown. The maximum flow for Norriseal valves is at maximum travel. The minimumcontrollable CV is where the Flow



Characteristic (CV vs. Travel) initially deviates or where the valve trim cannot maintain a consistent flow rate. The Trim’s rangeability is not always the useable range as seat erosion may be a governing factor. A valve with a significant pressure drop at low flow rates should not be used to throttle near the seat for extended periods of time.

The rangeability values, listed in Table 1, apply to the rated CV, not the required CV. For example, an application may require a maximum CV of 170. A 4” Equal Percentage Trim may be selected that has a maximum CV of 195. Using the rangeability value for this trim, the minimum CV is 195/100=19.5, not 170/100=17.

Valve applications subject to pressures from nature, such as gas and oil production, are usually sized for full flow at about 80% open as the pressure may be unknown when the valve is sized and the pressure may vary with time.

Those valve applications with fairly consistent inlet pressures, such as process control and power applications are usually sized at full travel. The valve specifier usually includes a fair margin of safety in the stated sizing conditions. If the valve supplier includes additional safety, such as full flow at 80% open, the valve may be at full flow at less than ½ travel giving poor performance.

Table 1 - TRIM RANGEABILITY

Valve TrimRang ability

Equal Percent - Balanced Cage Control 100:1Linear - Balanced Cage Control 100:1Quick Opening - Balanced Cage Control 30:1DB I - Balanced Cage Control 100:1DB II & CAV II - Balanced Cage Control 100:1Modified Percent - Balanced Plug Control 50:1Modified Percent - Unbalanced Plug Control 25:1V Control Ball 300:1

CV AND FLOW SIZING FORMULAS

The following formulas are for information and for understanding the sizing process. Norriseal’s Valve Sizing Program is recommended for the calculation process. Flow noise equations are not listed below as they are highly complex and should only be made on our verified computer program. Formulas are shown both for calculation the CV when the flow rate is known and for calculating the flow when the CV is known.

CV Formulas for Liquid Flow

Required FP P

P P FLV F

1 2

1

FP

PFV

C

0 96 0 28. .

If the Rated FL is larger than the Required FL:

CQ

F F

G

P Por Q C F F

P P

GVP R

fV P R

f

1 2

1 2

When the Rated FL is smaller than the Required FL, choked flow exists in the vena contracta limiting the flow.

If the Rated FL is smaller than the Required FL:

f

VFLPV

VF

f

LPV

G

PFPRatedFFCQ

or

PFP

G

RatedFF

QC

1

1

)(

P for choked flow F P F P psiL F V 21

P for incipient cavitation K P P psiC V 1

(See discussion in “Choked Flow and Incipient Cavitation” section)



CV Formulas for Vapor Flow

xP P

P

1 2

1

Limit x xT

Fk

K 14.

Yx

F xK T

13

If the flow rate is in volumetric units, SCFH, then

If the flow rate is in mass flow units, Lb./Hr.,

then

11

11

3.63

3.63

PxYFCW

or

PxYF

WC

PV

P

V

To convert SCFH to Lb./Hr.:W=0.0764 Q Gg = Lb./Hr.

Airof WeightMolecular

VaportheofWeightMolecular

VaporaofGravity Specific

CV Formulas for Two Phase Flow

Pressure Drop for liquid phase = VFLf PFPFP 1

2

Pressure Drop for vapor phase = P F x Pg K T 1

ff = weight fraction of total flow as liquid

fg = weight fraction of total flow as vapor

CW

F

f

P

f

P YVP

f

F f

g

g g

63 3 1 1

2.

FLOW VELOCITY FORMULAS

Flow Velocity for Liquid Flow

Liquid Flow Velocity through the Valve:

VQ

DFt SecV

b

0 408

2

../ .

Liquid Flow Velocity through the Pipe:

VQ

DFt SecP

P

0 408

2

../ .

Flow Velocity for Vapor Flow

Downstream Specific Volume for a Gas

Vapor: VT Z

M PFt Lb2

2

310 72

.. / .

Downstream Specific Volume for Steam: V2 Refer to Keenan & Keyes’ Steam Tables

Vapor Flow Velocity through the Valve:

./.234.006.3

222 MinFt

D

GQ

D

VWV

V

g

VV

Vapor Flow Velocity through the Pipe:

./.234.006.3

222 MinFt

D

GQ

D

VWV

P

g

PP

Sonic Velocity of a Vapor Fluid:

V P V Ft MinSONIC 4650 2 2 ./ .

Mach Number: SONIC

PV

V

VorVVelocityFlowVapor ,

ZTG

xYPFCQ

or

x

ZTG

YPF

QC

gPV

g

PV

1

1

1360

1360



NomenclatureCV = Valve Flow Coefficient.DB = Inside Diameter of Valve Body Outlet

= Inches. See Table 5.DP = Inside Diameter of Outlet Pipe =

Inches.FF = Liquid Critical Pressure Ratio Factor:Fk = Ratio of specific Heats Factor.FL = Liquid Pressure Recovery Factor.FL Required = The FL factor to avoid

Choked Flow.FL Rated = The FL factor rated for individual

Trim Styles. See Table 4.FP = Piping Geometry Factor, If the valve

size and pipe size are equal us 1.0, if not refer to ISA 75.01 section 4.3.

FR = Reynolds Number Factor, Normally = 1.0 but varies with very slow fluid velocities or very viscous fluids. Refer to ISA 75.01 section 4.4.

Gf = Specific Gravity of a Liquid relative to water at 60 F.

Gg = Specific Gravity of a Vapor relative to air at 60 F 14.7 PSIA.

k = Ratio of specific Heats. See Table 3.KC = Cavitation Index. See Table 4.M = Molecular Weight. See Table 3.P1 = Valve Inlet Pressure (psia).P2 = Valve Outlet Pressure (psia).PC = Fluid’s Critical Pressure (psia). See

Table 3.PV = Fluid’s Vapor Pressure (psia).Q = Volumetric Flow Rate:

Liquids (GPM) Vapor (SCFH)T = Fluid Temperature in Degrees

Rankine. R = F + 460.

2V = Specific Volume of vapor, either gas or steam = Ft.3 / Lb.

W = Mass Flow Rate = Lb./Hr.x = Pressure Drop Ratio.xT = Maximum Pressure Drop Ratio,

varies with Trim Style. See Table 4.Y = Fluid Expansion Factor for vapor flow.Z = Compressibility Factor for vapor flow.

Usually 1.0. Refer ISA Handbook of Control Valves, 2nd Edition, pages 488-490.

= Specific Weight = Lb./Ft.3

Subscripts:1 = Inlet conditions2 = Outlet conditionsv = Valvep = Pipef = Liquidg = Vaporb = Body



Flow velocity of a vapor, gas or steam, physically cannot exceed sonic velocity or Mach 1.0. Vapor flow is physically limited at sonic velocity and becomes choked. The choked sonic limitation may apply either at the valve trim or at the valve body’s outlet. When the flow rate increases with the velocity at the valve’s outlet at sonic, the valve’s outlet pressure will rise increasing the fluid density and allowing a higher flow rate still limited at sonic velocity. When a sizing program shows a Valve MACH Number exceeding 1, the inputted outlet pressure is incorrect. Increase P2 until the MACH number equal 1.0. This determines the valve’s outlet pressure that develops to increase the fluid density sufficiently for the fluid to flow out of the valve at sonic velocity. The specifier may write a lower pressure that may occur further downstream after the piping system causes additional pressure drops.

The ISA noise prediction formulas for vapor flow loses accuracy at Mach numbers larger than .33.

Conversion to Cg and Cs

Not all valve suppliers use the ISA sizing coefficient and may use a Cg or Cs value instead. The ISA CV coefficient can be converted to Cg or Cs using these equations.

C C conversion factorg V

C

C conversion factors

V20

CC

conversion factorV

g

CC

conversion factorV

s20

Table 2 - Cg Conversion FactorsValveSize

General DB I DB II

1” 32.3 35.1 301.5” 32.7 37.8 302” 32.6 38.8 303” 32.2 38.1 304” 33.5 38.9 306” 34.8 N/A 308” 35.6 N/A 30



Table 3 - FLUID PROPERTIES

Name of

Fluid

Fluid FormLiquidGas

Molecular Weight

M

CriticalPressure

Pc psia

CriticalTemperature

Tc (F)

Ratio of specificHeats

kAcetylene G 26.038 905.04 95.27 1.26Air G 28.966 546. 79 -220.99 1.4Ammonia L G 17.031 1637.48 270.59 1.31Argon G 39.948 706.34 -188.23 1.668Benzene L G 78.114 713.59 552.11 1.08Butane G 58.124 529.39 274.91 1.1Butanol L 74.123 639.62 553.55Butene-1 G 56.108 583.4 295.6 1.11Butylene Oxide L 63.6Butadiene L 54.092 652.5 339 1.121-Butene L 56.108 583.4 295.6 1.11n-Butane G 58.1243 551.1 305.7 1.1Isobutane G 58.124 529.10 274.90 1.11n-Butanol L 638.3Isobutylene L 56.108 580.5 292.6 1.12Carbon Dioxide L G 44.01 1070.38 87.71 1.295Carbon Monoxide L G 28.01 507.63 -220.45 1.395Carbon Tetrachloride L 153.82 661.37 541.85 1.067Chlorine L G 70.906 1116.79 291.29 1.355Chlorobenzene L 112.559 655.62 678.32 1.1Chloroform L 119.38 786.11 505.13Chloroprene L 616.5Cyclobutane L 56.108 723.24 367.82 1.14Cyclohexane L 84.162 590.30 536.45Cyclopentane L 70.135 654.15 460.88 1.11Cyclopropane L 42.081 797.71 256.37Crude Oil LEthane L G 30.07 707.79 90.05 1.18Ethanol L 46.069 925.34 469.49 1.13Ethylbenzene L 106.168 523.2 651.1 1.072Ethyl Chloride G 64.515 754.20 369.05 1.13Ethyl Oxide L 1052.2Ethylene L G 28.054 732.44 49.91 1.22Ethylene Glycol L 62.069 1117.2Triethylene Glycol LFreon 11 L G 137.37 635.00 338.00 1.14Freon 12 L G 120.92 596.90 234.00 1.14Freon 22 L G 86.48 716.00 204.80 1.18Helium G 4.003 33.36 -450.33 1.66Heptane G 100.205 396.8 512.7 1.05Hydrazine L 32.045 2132.06 716.09Hydrogen L G 2.016 188.55 -399.73 1.412Hydrogen Bromide L 80.912 1240 193.76 1.4Hydrogen Chloride L G 36.461 1205.27 124.79 1.41Hydrogen Floride L 20.006 941.30 370.49Hydrogen Iodide L 127.91 1205.27 303.35Hydrogen Sulphide G 34.076 1296.64 229.91 1.32



Name of

Fluid

Fluid FormLiquidGas

Molecular Weight

M

CriticalPressure

Pc psia

CriticalTemperature

Tc (F)

Ratio of specificHeats

kIsoprene L 532.1Methane L G 16.043 667.17 -116.77 1.31Methanol L 32.042 1153.05 463.01Methyl Chloride L G 50.49 968.85 289.67 1.21-Methylchloride L 84.922 889.08 458.33O-Methylene Chloride L 910.9Napthalene L 128.17 587.40 887.45Natural Gas G 19.5 670 -80 1.27Neon G 20.179 400.30 -379.75 1.667Nitric Oxide L G 30.006 941.30 -135.67Nitrogen L G 28.013 493.13 -232.51 1.4Nitrogen Dioxide L 46.006 1479.8 316.52 1.29Nitrous Oxide L G 44.013 1050.08 97.61n-Nonane G 128.259 335.1 610.6 1.04n-Octane G 114.23 362.60 456.35 1.05Oxygen L G 31.999 730.99 -181.39 1.397Pentane G 72.151 488.78 385.61 1.07Phenol L 94.113 889.56 789.56 1.09Propane L G 44.097 617.86 205.97 1.13n-Propanol L 751.3Propene G 42.1 661 198 1.14Propylene L 42.081 667.17 197.51 1.154Propyl Oxide L 714.7Sea Water/Brine L 18 3200 705.47 1.33Sulfuric Acid LSulfur Dioxide L G 64.059 1142.90 315.59 1.29Sulfur Trioxide L 80.058 1190.7 423.8Tolulene L 92.141 587.40 609.53 1.06Water L G 18.015 3208.24 705.47 1.335M-Xylene L 106.168 514.4 650.9 1.072O-xylene L 106.168 540.8 674.7 1.049P-xylene L 106.168 510 649.5 1.073

Table 4 - FL, KC & XT Factors

Valve Trim StyleFL

RatedKC XT

CAV II Cage Control .94 .80 DB I Cage Control .75DB II Cage Control .75Plug Control (Flow Up) .90 .65 .70Ported Cage Control (Flow Up) .90 .65 .70Ported Cage Control (Flow Down) .90 .65 .75Butterfly Valve .65 .30 .38V Control Ball Valve .57 .22 .25 = No value for vapor flow = No value for liquid flow



Table 5 - Flanged Body Inlet and Outlet DiametersNominal ANSI Pressure ClassBody Size 150 300 600 900 1500 2500

1 1.06" 1.06" 1.06" 1.00" 1.00" 1.00"1.5 1.63" 1.63" 1.63" 1.63" 1.63" 1.50"2 2.06" 2.00" 2.00" 2.00" 2.00" 1.75"3 3.00" 3.00" 3.00" 3.00" 2.69" 2.69"4 4.00" 4.00" 4.00" 4.00" 3.69" 3.44"6 6.00" 6.00" 6.00" 5.75" 5.75" 5.50"8 8.00" 8.00" 8.00" 7.62" 7.25" 7.00"

SEAT LEAKAGE

The Fluids Control Institute (FCI) Standard ANSI/FCI 70.2 establishes a Valve’s allowable seat Leakage Rate. The standard recognizes five degrees of seat tightness.

Table 6 - ALLOWABLE SEAT LEAKAGE CLASSES

Leakage ClassMaximum Seat

LeakageTest Fluid

TestPressure

Relative SeatTightness

Class II 0.5% of rated CV Water 45 to 60 PSI 1.0Class IIA (Norriseal) 0.2% of rated CV Water 45 to 60 PSI 2.5Class III 0.1% of rated CV Water 45 to 60 PSI 5.0Class IV 0.01% of rated CV Water 45 to 60 PSI 50

Class V0.0005 ml /min/inch of trim size/ P(PSI)

WaterMax OperatingP

300,000

Class VI About 0.9 ml/min Air 50 PSI 600,000 Leakage rate varies by valve size, Refer to the Standard ANSI/FCI 70.2.Norriseal offers Class IIA (Norriseal), Class IV, Class V & Class IVThe Relative Seat Tightness is at a 50 P. For example, a Class IV leakage rate is 1/50 as much as Class IIClass VI is for resilient seated valves; the other classes are for metallic seats.

ACTUATOR SIZING

The actuator sizing process matches our actuator’s force output with our valve trim’s required stem forces. The result is the maximum obtainable pressure drop at the different seat leakage classes. The process considers the valve’s shut off

condition. The flowing conditions also require an adequate match between the actuator and trim forces but the shut off condition is dominant and determines the allowable.

UA UnbalancedArea BalancedTrim Cage ID Seat ID

2 2

4

= In2

UA UnbalancedArea UnbalancedTrim Seat ID

2

4

= In2

CL Seat Contact Load Seat ID Load Factor = Lb./In. of circumferenceLoad Factors vary with seat leakage class



PF = Packing Friction (Teflon Packing)= 25 Lb.PF = Packing Friction (Grafoil Packing)= (Stem Dia.) (P1) (Packing Height) (.15)

PF for Grafoil Packing friction should never be less than 25 Lb.

RF Plug Seal Ring Friction Cage ID Cage ID Seal Groove P 24

0 032 2

.

Direct Actuator Output = (Effective Diaph. Area) (Actuator Press.- Final Spring Pressure)Reverse Actuator Output = (Effective Diaph. Area) (Initial Final Spring Pressure)

The “Initial Spring Pressure” is the actuator pressure when the valve stem begins to move.The “Final Spring Pressure” is the actuator pressure when the valve stem reaches full travel.

Allowable P

Actuator Output PF RF CL

UA

For Balanced Trim Flow to Close

Allowable P

Actuator Output PF CL

UA

For Unbalanced Trim Flow to Open

P Tables

The following eleven tables contain calculated P pressures, in psi, using the above formulas. The first four tables are for No. 9, 12, 16, & 18 actuators and valves with balanced trim and Teflon packing, the second four are with Grafoil packing.. The four Grafoil packing tables show lower allowable due to the significantly higher friction with Grafoil packing. The last three are for unbalanced trims with No. 9, 12 & 16 actuators.

The difference in the allowable P pressures for the Seat Leakage Classes requires different seat contact forces. A lower leakage rate, except for Class VI, is obtained by increasing the net seat contact force. Leakage Classes IV & VI (resilient seat) share the same contact forces and allowable pressures even though their leakage rates are quite different.

The allowable pressure drop cannot exceed the Body’s ANSI pressure rating.

The table’s first column for direct acting actuators is the air supply pressure to the actuator. A 3-15 psi actuator spring is assumed. If a 6-30 psi spring is used in a direct actuator, add 15 to the pressure in the first column.

The table’s first column for reverse acting actuators is the initial pressure corresponding to the amount of compression in the actuator’s spring when the valve is closed. The “Initial air pressure is actuator diaphragm pressure when the valve begins to open. The final air pressure is determined by adding 12 psi to the initial air pressure of a 3-15 psi spring and by adding 24 psi to the initial air pressure of a 6-30 psi.



Table 7ALLOWABLE PRESSURE DROP RATINGS FOR 2700A CAGE CONTROL TRIM

TEFLON PACKING, FLOW DOWN, No. 9 Direct Actuator, 3 to 15 psi SpringAllowable Pressure Drops (PSI)

Trim SizeAir Supply Pressure

Leakage Class

1” 1.5” 2” 3” 4”18 II 94 2318 IV & VI18 V20 II 312 223 175 9220 IV & VI 5920 V22 II 529 423 370 278 14422 IV & VI 277 8222 V24 II 747 623 564 465 29624 IV & VI 494 282 16524 V27 II 1,074 923 855 744 52327 IV & VI 821 583 457 23327 V30 II 1,400 1,223 1,147 1,024 75130 IV & VI 1,147 883 748 513 19730 V 1033 II 1,726 1,524 1,438 1,304 97933 IV & VI 1,474 1,183 1,039 792 42533 V 33636 II 1,944 1,724 1,633 1,490 1,13036 IV & VI 1,691 1,383 1,234 979 57736 V 554

Usually direct acting actuators use a 3-15 psi spring. With an 18 psi air supply pressure, there is a 3 psi (18-15=3) net closure force on the trim, or for a 27 psi supply the net closure force is 12 psi. If a 6-30 psi spring is used in a direct acting actuator, add 15 to pressure in the air supply column.

ALLOWABLE PRESSURE DROP RATINGS FOR 2700A CAGE CONTROL TRIMTEFLON PACKING, FLOW DOWN, No. 9 Reverse Actuator

Allowable Pressure Drops (PSI)Trim SizeInitial Air

Pressure*Leakage

Class1” 1.5” 2” 3” 4”

3 II 94 233 IV & VI3 V6 II 421 323 273 185 686 IV & VI 1686 V9 II 747 623 564 465 2969 IV & VI 494 282 1659 V

12 II 1,074 923 855 744 52312 IV & VI 821 583 457 23312 V

The Initial air pressure is actuator diaphragm pressure when the valve begins to open. For example, a 3-15 has an initial pressure of 3 psi. The spring may have additional compression to provide the 6, 9 and 12 psi initial pressures.



Table 8ALLOWABLE PRESSURE DROP RATINGS FOR 2700A CAGE CONTROL TRIMTEFLON PACKING, FLOW DOWN, No.12 Direct Actuator, 3 to 15 psi Spring

Allowable Pressure Drops (PSI)Trim Size

AirSupply

Pressure

LeakageClass

1" 1.5" 2" 3" 4"18 II 421 323 273 185 6818 IV & VI 16818 V20 II 856 723 661 558 37220 IV & VI 603 382 262 4720 V22 II 1,291 1,123 1,050 931 67522 IV & VI 1,038 783 651 420 12122 V -24 II 1,726 1,524 1,438 1,304 97924 IV & VI 1,474 1,183 1,039 792 42524 V 336 -27 II 2,379 2,124 2,021 1,863 1,43427 IV & VI 2,126 1,784 1,622 1,352 88027 V 989 25130 II 3,032 2,725 2,604 2,422 1,89030 IV & VI 2,779 2,384 2,205 1,911 1,33630 V 1,642 851 41033 II 3,685 3,325 3,187 2,981 2,34533 IV & VI 3,432 2,984 2,788 2,470 1,79133 V 2,295 1,452 993 17136 II 4,120 3,725 3,575 3,354 2,64936 IV & VI 3,867 3,385 3,177 2,843 2,09536 V 2,730 1,852 1,382 543


ALLOWABLE PRESSURE DROP RATINGS FOR 2700A CAGE CONTROL TRIMTEFLON PACKING, FLOW DOWN, No. 12 Reverse Actuator


InitialAir

Pressure*

LeakageClass

1" 1.5" 2" 3" 4"3 II 421 323 273 185 683 IV & VI 1683 V6 II 1,074 923 855 744 5236 IV & VI 821 583 457 2336 V9 II 1,726 1,524 1,438 1,304 9799 IV & VI 1,474 1,183 1,039 792 4259 V 33612 II 2,379 2,124 2,021 1,863 1,43412 IV & VI 2,126 1,784 1,622 1,352 88012 V 989 251

The Initial air pressure is actuator diaphragm pressure when the valve begins to open. For example, a 3-15 has an initial pressure of 3 psi. The spring may have additional compression to provide the 6, 9 & 12 psi initial pressures.




TEFLON PACKING, FLOW DOWN, No.16 Direct Actuator, 3 to 15 psi SpringAllowable Pressure Drops (PSI)

Trim SizeAir

SupplyPressure

LeakageClass

1" 1.5" 2" 3" 4"18 II 887 752 689 584 39318 IV & VI 634 411 290 7318 V20 II 1,633 1,438 1,355 1,224 91420 IV & VI 1,380 1,097 956 713 36020 V 24322 II 2,379 2,124 2,021 1,863 1,43422 IV & VI 2,126 1,784 1,622 1,352 88022 V 989 25124 II 3,125 2,810 2,687 2,502 1,95524 IV & VI 2,873 2,470 2,288 1,991 1,40124 V 1,735 937 49427 II 4,244 3,840 3,686 3,461 2,73527 IV & VI 3,992 3,499 3,288 2,950 2,18127 V 2,854 1,966 1,493 65030 II 5,364 4,869 4,686 4,420 3,51630 IV & VI 5,111 4,529 4,287 3,908 2,96230 V 3,973 2,996 2,492 1,609 47033 II 6,483 5,899 5,685 5,378 4,29733 IV & VI 6,230 5,558 5,286 4,867 3,74333 V 5,093 4,025 3,491 2,568 1,25036 II 7,229 6,585 6,351 6,017 4,81736 IV & VI 6,976 6,244 5,952 5,506 4,26336 V 5,839 4,711 4,157 3,207 1,777


ALLOWABLE PRESSURE DROP RATINGS FOR 2700A CAGE CONTROL TRIMTEFLON PACKING, FLOW DOWN, No.16 Reverse Actuator


InitialAir

PressureLeakage

Class1" 1.5" 2" 3" 4"

3 II 887 752 689 584 3933 IV & VI 634 411 290 733 V6 II 2,006 1,781 1,688 1,543 1,1746 IV & VI 1,753 1,440 1,289 1,032 6206 V 6169 II 3,125 2,810 2,687 2,502 1,9559 IV & VI 2,873 2,470 2,288 1,991 1,4019 V 1,735 937 49412 II 4,244 3,840 3,686 3,461 2,73512 IV & VI 3,992 3,499 3,288 2,950 2,18112 V 2,854 1,966 1,493 650





TEFLON PACKING, FLOW DOWN, No.18 Direct Actuator, 3 to 15 psi SpringAllowable Pressure Drops (PSI)

Trim SizeAir

SupplyPressure

LeakageClass

1" 1.5" 2" 3" 4" 6” 8”18 II 1,447 1,266 1,189 1,064 784 333 17718 IV & VI 1,194 926 790 553 23018 V 56 5620 II 2,566 2,296 2,188 2,023 1,564 759 50020 IV & VI 2,313 1,955 1,789 1,512 1,010 300 2420 V 1,176 42222 II 3,685 3,325 3,187 2,981 2,345 1,185 82422 IV & VI 3,432 2,984 2,788 2,470 1,791 726 34822 V 2,29524 II 4,804 4,354 4,186 3,940 3,126 1,611 1,14724 IV & VI 4,551 4,014 3,787 3,429 2,572 1,152 67124 V 3,414 2,481 1,992 1,129 7927 II 6,483 5,899 5,685 5,378 4,297 2,250 1,63227 IV & VI 6,230 5,558 5,286 4,867 3,743 1,791 1,15627 V 5,093 4,025 3,491 2,568 1,25030 II 8,161 7,443 7,183 6,816 5,468 2,889 2,11730 IV & VI 7,909 7,102 6,785 6,305 4,914 2,430 1,64130 V 6,771 5,569 4,990 4,006 2,421 36333 II 9,840 8,987 8,682 8,255 6,639 3,528 2,60233 IV & VI 9,587 8,646 8,283 7,744 6,085 3,069 2,12733 V 8,450 7,113 6,489 5,444 3,592 1,00236 II 10959 10,016 9,681 9,213 7,419 3,954 2,92636 IV & VI 10706 9,675 9,283 8,702 6,866 3,495 2,45036 V 9,569 8,143 7,488 6,403 4,373 1,428 309




InitialAir

Pressure

LeakageClass

1" 1.5" 2" 3" 4" 6” 8”3 II 1,447 1,266 1,189 1,064 784 333 1773 IV & VI 1,194 926 790 553 2303 V 566 II 3,125 2,810 2,687 2,502 1,955 972 6626 IV & VI 2,873 2,470 2,288 1,991 1,401 513 1866 V 1,735 937 4949 II 4,804 4,354 4,186 3,940 3,126 1,611 1,1479 IV & VI 4,551 4,014 3,787 3,429 2,572 1,152 6719 V 3,414 2,481 1,992 1,129 7912 II 6,483 5,899 5,685 5,378 4,297 2,250 1,63212 IV & VI 6,230 5,558 5,286 4,867 3,743 1,791 1,15612 V 5,093 4,025 3,491 2,568 1,250 The Initial air pressure is actuator diaphragm pressure when the valve begins to open. For example, a 3-

15 has an initial pressure of 3 psi. The spring may have additional compression to provide the 6, 9 & 12 psi initial pressures.




GRAFOIL PACKING, FLOW DOWN, No.9 Direct Actuator, 3 to 15 psi SpringAllowable Pressure Drops (PSI)

Trim SizeAir

SupplyPressure

LeakageClass

1" 1.5" 2" 3" 4"18 II 94 2318 IV & VI18 V20 II 299 223 175 9220 IV & VI 5920 V22 II 453 381 343 275 14422 IV & VI 274 8222 V24 II 607 527 487 415 29024 IV & VI 428 278 16524 V27 II 838 747 702 625 47127 IV & VI 659 498 407 23327 V30 II 1,070 967 918 835 65330 IV & VI 891 718 623 451 19730 V 1033 II 1,301 1,187 1,133 1,045 83433 IV & VI 1,122 937 838 661 39333 V 31636 II 1,455 1,333 1,277 1,185 95536 IV & VI 1,376 1084 982 801 51436 V 470




Initial Air

Pressure

LeakageClass

1" 1.5" 2" 3" 4"3 II 94 233 IV & VI3 V6 II 376 308 271 185 686 IV & VI 1686 V9 II 607 527 487 415 2909 IV & VI 428 278 1659 V12 II 838 747 702 625 47112 IV & VI 659 498 407 23312 V




Table 12ALLOWABLE PRESSURE DROP RATINGS FOR 2700A CAGE CONTROL TRIMGRAFOIL PACKING, FLOW DOWN, No.12 Direct Actuator, 3 to 15 psi Spring


AirSupply

Pressure

LeakageClass

1" 1.5" 2" 3" 4"18 II 376 308 271 185 6818 IV & VI 16818 V20 II 684 601 559 485 35020 IV & VI 505 351 262 4720 V22 II 993 894 846 765 59222 IV & VI 813 644 551 381 12122 V24 II 1,301 1,187 1,133 1,045 83424 IV & VI 1,122 937 838 661 39324 V 31627 II 1,763 1,626 1,565 1,464 1,19727 IV & VI 1,584 1,377 1,270 1,081 75627 V 778 25130 II 2,226 2,066 1,996 1,884 1,56030 IV & VI 2,047 1,816 1,701 1,500 1,11830 V 1,241 694 37333 II 2,689 2,505 2,427 2,304 1,92233 IV & VI 2,510 2,256 2,132 1,920 1,48133 V 1,704 1,134 804 17136 II 2,997 2,798 2,714 2,583 2,16436 IV & VI 2,818 2,549 2,419 2,200 1,72336 V 2,012 1,427 1,092 474


ALLOWABLE PRESSURE DROP RATINGS FOR 2700A CAGE CONTROL TRIMGRAFOIL PACKING, FLOW DOWN, No.12 Reverse Actuator


Initial Air

Pressure

LeakageClass

1" 1.5" 2" 3" 4"3 II 376 308 271 185 683 IV & VI 1683 V6 II 838 747 702 625 4716 IV & VI 659 498 407 2336 V9 II 1,301 1,187 1,133 1,045 8349 IV & VI 1,122 937 838 661 3939 V 316

12 II 1,763 1,626 1,565 1,464 1,19712 IV & VI 1,584 1,377 1,270 1,081 75612 V 778 251






AirSupply

Pressure

LeakageClass

1" 1.5" 2" 3" 4"18 II 706 622 579 505 36818 IV & VI 527 372 284 7318 V20 II 1,235 1124 1072 985 78220 IV & VI 1,056 875 777 601 34120 V 24322 II 1,763 1,626 1,565 1,464 1,19722 IV & VI 1,584 1,377 1,270 1,081 75622 V 778 25124 II 2,292 2,129 2,057 1,944 1,61124 IV & VI 2,113 1,879 1,762 1,560 1,17024 V 1,307 757 43527 II 3,085 2,882 2,797 2,663 2,23327 IV & VI 2,906 2,633 2,502 2,280 1,79227 V 2,100 1,511 1,174 55430 II 3,878 3,635 3,536 3,383 2,85530 IV & VI 3,699 3,386 3,241 2,999 2,41430 V 2,893 2,264 1,913 1,274 42833 II 4,671 4,389 4,275 4,102 3,47733 IV & VI 4,492 4,140 3,980 3,719 3,03633 V 3,686 3,018 2,652 1,993 1,05036 II 5,200 4,891 4,768 4,582 3,89236 IV & VI 5,021 4,642 4,473 4,198 3,45136 V 4,215 3,520 3,145 2,473 1,465




Initial Air

Pressure

LeakageClass

1" 1.5" 2" 3" 4"3 II 706 622 579 505 3683 IV & VI 527 372 284 733 V6 II 1,499 1,375 1,318 1,224 9906 IV & VI 1,320 1,126 1,023 841 5486 V 5149 II 2,292 2,129 2,057 1,944 1,6119 IV & VI 2,113 1,879 1,762 1,560 1,1709 V 1,307 757 43512 II 3,085 2,882 2,797 2,663 2,23312 IV & VI 2,906 2,633 2,502 2,280 1,79212 V 2,100 1,511 1,174 554






AirSupply

Pressure

LeakageClass

1" 1.5" 2" 3" 4" 6” 8”18 II 1,103 998 949 865 679 311 17518 IV & VI 924 749 654 481 23018 V 5620 II 1,896 1,752 1,688 1,584 1,301 671 45520 IV & VI 1,717 1,502 1,393 1,201 859 283 2420 V 911 38122 II 2,689 2,505 2,427 2,304 1,922 1,031 73522 IV & VI 2,510 2,256 2,132 1,920 1,481 643 32322 V 1,704 1,134 804 17124 II 3,482 3,259 3,166 3,023 2,544 1,391 1,01524 IV & VI 3,303 3,009 2,871 2,639 2,103 1,003 60324 V 2,497 1,887 1,543 914 7927 II 4,671 4,389 4,275 4,102 3,477 1,930 1,43527 IV & VI 4,492 4,140 3,980 3,719 3,036 1,542 1,02327 V 3,686 3,018 2,652 1,993 1,05030 II 5,861 5,519 5,384 5,181 4,410 2,470 1,85430 IV & VI 5,681 5,270 5,089 4,798 3,969 2,082 1,44330 V 4,876 4,148 3,761 3,072 1,983 33633 II 7,050 6,649 6,492 6,260 5,343 3,010 2,27433 IV & VI 6,871 6,400 6,197 5,877 4,902 2,622 1,86233 V 6,065 5,278 4,870 4,151 2,916 87636 II 7,843 7,403 7,232 6,980 5,965 3,369 2,55436 IV & VI 7,664 7,153 6,937 6,596 5,524 2,982 2,14236 V 6,858 6,031 5,609 4,871 3,538 1,236 290




Initial Air

Pressure

LeakageClass

1" 1.5" 2" 3" 4" 6” 8”3 II 1,103 998 949 865 679 311 1753 IV & VI 924 749 654 481 2303 V 566 II 2,292 2,129 2,057 1,944 1,611 851 5956 IV & VI 2,113 1,879 1,762 1,560 1,170 463 1836 V 1,307 757 4359 II 3,482 3,259 3,166 3,023 2,544 1,391 1,0159 IV & VI 3,303 3,009 2,871 2,639 2,103 1,003 6039 V 2,497 1,887 1,543 914 7912 II 4,671 4,389 4,275 4,102 3,477 1,930 1,43512 IV & VI 4,492 4,140 3,980 3,719 3,036 1,542 1,02312 V 3,686 3,018 2,652 1,993 1,050 The Initial air pressure is actuator diaphragm pressure when the valve begins to open. For example, a 3-




Table 15ALLOWABLE PRESSURE DROP RATINGS FOR 2700A PLUG CONTROL TRIM, TEFLON PACKING

FLOW UP, Direct Actuators, 3 to 15 psi SpringAllowable Pressure Drops (PSI)

Trim SizeNo 12 Direct Actuator No 16 Direct Actuator No 18 Direct Actuator

AirSupplyPressure

LeakageClass

1.5" 2" 3" 4" 1.5" 2" 3" 4" 1.5" 2" 3" 4" 6” 8"II 1160 990 630 410 1980 1700 1080 700 2970 2550 1610 1060 650 30018 IV 580 530 290 190 1000 910 500 320 1500 1370 750 480 320 90II 1290 1100 700 460 2200 1890 1200 780 3300 2830 1790 1170 720 33020IV 970 890 490 310 1660 1520 840 530 2490 2280 1250 800 540 150II 1410 1210 770 500 2420 2080 1310 860 3640 3110 1970 1290 800 36022IV 1360 1240 680 430 2330 2130 1170 740 3490 3200 1760 1120 750 220II 1540 1320 840 550 2640 2260 1430 940 3970 3400 2150 1410 870 40024IV 1750 1600 880 560 2990 2740 1500 960 4490 4110 2260 1440 970 280II 1740 1490 940 620 2970 2550 1610 1060 4460 3820 2420 1580 980 45027IV 2330 2130 1170 740 3990 3650 2010 1280 5990 5480 2260 1910 1290 370II 1930 1650 1050 680 3300 2830 1790 1170 4960 4240 2690 1760 1090 50030IV 2910 2660 1460 930 4990 4570 2510 1590 5990 5480 2260 2390 1610 460II 2120 1820 1150 750 3640 3110 1970 1290 5450 4670 2960 1940 1190 55033IV 3490 3200 1760 1120 5990 5480 3010 1910 5990 5480 2260 2390 1610 550II 2250 1930 1220 800 3860 3300 2090 1370 5780 4950 3140 2050 1270 58036IV 3880 3550 1950 1240 6650 6090 3340 2130 5990 5480 2260 2390 2150 620


ALLOWABLE PRESSURE DROP RATINGS FOR 2700A PLUG CONTROL TRIM, TEFLON PACKINGFLOW UP, Reverse Actuators


No 12 Direct Actuator No 16 Direct Actuator No 18 Direct Actuator

Initial *Air

Pressure

LeakageClass

1.5" 2" 3" 4" 1.5" 2" 3" 4" 1.5" 2" 3" 4" 6” 8"II 1160 990 630 410 1980 1700 1080 700 2970 2550 1610 1060 650 3003IV 580 530 290 190 1000 910 500 320 1500 1370 750 480 320 90II 1350 1160 730 480 2310 1980 1250 820 3470 2970 1880 1230 760 3506IV 1160 1070 590 370 2000 1830 1000 640 2990 2740 1500 960 650 180II 1540 1320 840 550 2640 2260 1430 940 3970 3400 2150 1410 870 4009IV 1750 1600 880 560 2990 2740 1500 960 4490 4110 2260 1440 970 280II 1740 1490 940 620 2970 2550 1610 1060 4460 3820 2420 1580 980 45012IV 2330 2130 1170 740 3990 3650 2010 1280 5990 5480 2260 1910 1290 370




Table 16ALLOWABLE PRESS. DROP RATINGS FOR UNBALANCED TRIM

TEFLON PACKING, FLOW UP, No.9 Direct Actuator, 3 to 15 psi SpringAllowable Pressure Drops (PSI)

Trim SizeAir

SupplyPressure

LeakageClass

.125” .187" .250" .375" .500 .750 1.00018 II 6,199 2,684 1,470 618 327 128 6218 IV & VI 5,560 2,257 1,150 404 167 2118 V 2,679 33720 II >10000 5,220 2,896 1,251 684 286 15120 IV & VI >10000 4,792 2,576 1,038 524 180 7120 V >10000 2,872 1,136 7822 II >10000 7,754 4,322 1,885 1,040 445 24022 IV & VI >10000 7,328 4,002 1,672 880 338 16022 V >10000 5,408 2,562 712 16024 II >10000 >10000 5,748 2,519 1,397 603 32924 IV & VI >10000 9,863 5,428 2,306 1,237 496 24924 V >10000 7,943 3,988 1,346 517 1627 II >10000 >10000 7,887 3,470 1,932 841 46327 IV & VI >10000 >10000 7,567 3,256 1,772 734 38327 V >10000 >10000 6,127 2,296 1,052 254 2330 II >10000 >10000 >10000 4,420 2,466 1,078 59730 IV & VI >10000 >10000 9,706 4,207 2,306 972 51730 V >10000 >10000 8,266 3,247 1,586 492 15733 II >10000 >10000 >10000 5,371 3,001 1,316 73033 IV & VI >10000 >10000 >10000 5,158 2,841 1,209 65033 V >10000 >10000 >10000 4,198 2,121 729 29036 II >10000 >10000 >10000 6,005 3,358 1,475 81936 IV & VI >10000 >10000 >10000 5,792 3,198 1,368 73936 V >10000 >10000 >10000 4,832 2,478 888 379


ALLOWABLE PRESS. DROP RATINGS FOR UNBALANCED TRIMTEFLON PACKING, FLOW UP, No.9 Reverse Actuator


Initial Air

Pressure

LeakageClass

.125” .187" .250" .375" .500 .750 1.0003 II 6,199 2,684 1,470 618 327 128 623 IV & VI 5,560 2,257 1,150 404 167 213 V 2,679 3376 II >10000 6,487 3,609 1,568 862 365 1966 IV & VI >10000 6,060 3,289 1,355 702 259 1166 V >10000 4140 1,849 3959 II >10000 >10000 5,748 2,519 1,397 603 3299 IV & VI >10000 9,863 5,428 2,306 1,237 496 2499 V >10000 7,943 3,988 1,346 517 1612 II >10000 >10000 7,887 3,470 1,932 841 46312 IV & VI >10000 >10000 7,567 3,256 1,772 734 38312 V >10000 >10000 6,127 2,296 1,052 254 23 The Initial air pressure is actuator diaphragm pressure when the valve begins to open. For example, a 3-






Trim SizeAir

SupplyPressure

LeakageClass

.187" .250" .375" .500 .750 1.00018 II 6,487 3,609 1568 862 365 19618 IV & VI 6,060 3,289 1355 702 259 11618 V 4,140 1,849 39520 II >10000 6,461 2,836 1,575 682 37420 IV & VI >10000 6,141 2,626 1,415 576 29420 V 9,210 4,701 1,663 695 9622 II >10000 9,313 4,104 2,288 999 55222 IV & VI >10000 8,993 3,890 2,128 893 47222 V >10000 7,553 2,930 1,408 413 11224 II >10000 >10000 5,371 3,001 1,316 73024 IV & VI >10000 >10000 5,158 2,841 1,209 65024 V >10000 >10000 4,198 2,121 729 29027 II >10000 >10000 7,272 4,071 1,791 99827 IV & VI >10000 >10000 7,059 3,911 1,685 91827 V >10000 >10000 6,099 3,191 1,205 55830 II >10000 >10000 9,174 5,140 2,267 1,26530 IV & VI >10000 >10000 8,961 4,980 2,160 1,18530 V >10000 >10000 8,001 4,260 1,680 82533 II >10000 >10000 >10000 6,210 2,742 1,53233 IV & VI >10000 >10000 >10000 6,050 2,635 1,45233 V >10000 >10000 9,902 5,330 2,155 1,09236 II >10000 >10000 >10000 6,923 3,059 1,71136 IV & VI >10000 >10000 >10000 6,763 2,952 1,63136 V >10000 >10000 >10000 6,043 2,472 1,271




Initial Air

Pressure

LeakageClass

.187" .250" .375" .500 .750 1.0003 II 6,487 3,609 1,568 862 365 1963 IV & VI 6,060 3,289 1,355 702 259 1163 V 4,140 1,849 3956 II >10000 7,887 3,470 1,932 841 4636 IV & VI >10000 7,567 3,256 1,772 734 3836 V >10000 6,127 2,296 1,052 254 239 II >10000 >10000 5,371 3,001 1,316 7309 IV & VI >10000 >10000 5,158 2,841 1,209 6509 V >10000 >10000 4,198 2,121 729 29012 II >10000 >10000 7,272 4,071 1,791 99812 IV & VI >10000 >10000 7,059 3,911 1,685 91812 V >10000 >10000 6,099 3,191 1,205 558 The Initial air pressure is actuator diaphragm pressure when the valve begins to open. For example, a 3-






Trim SizeAir

SupplyPressure

LeakageClass

.250" .375" .500 .750 1.00018 II 6,665 2,926 1626 705 38718 IV & VI 6,345 2,713 1466 598 30718 V 4,905 1,753 746 11820 II >10000 5,099 2,848 1,248 69220 IV & VI >10000 4,886 2,688 1,114 61220 V 9,794 3,926 1,968 662 25222 II >10000 7,272 4,071 1,791 99822 IV & VI >10000 7,059 3,911 1,685 91822 V >10000 6,099 3,191 1,205 55824 II >10000 9,445 5,293 2,335 1,30324 IV & VI >10000 9,232 5,133 2,228 1,22324 V >10000 8,272 4,413 1,748 86327 II >10000 >10000 7,127 3,150 1,76227 IV & VI >10000 >10000 6,967 3,043 1,68227 V >10000 >10000 6,247 2,563 1,32230 II >10000 >10000 8,960 3,964 2,22030 IV & VI >10000 >10000 8,800 3,858 2,14030 V >10000 >10000 8,080 3,378 1,78033 II >10000 >10000 >10000 4,779 2,67833 IV & VI >10000 >10000 >10000 4,673 2,59833 V >10000 >10000 9,913 4,193 2,23836 II >10000 >10000 >10000 5,323 2,98436 IV & VI >10000 >10000 >10000 5,216 2,90436 V >10000 >10000 >10000 4,736 2,544




Initial Air

Pressure

LeakageClass

.250" .375" .500 .750 1.0003 II 6,665 2,926 1,626 705 3873 IV & VI 6,345 2,713 1,466 598 3073 V 4,905 1,753 746 1186 II >10000 6,186 3,460 1,520 8456 IV & VI >10000 5,973 3,300 1,413 7656 V >10000 5,013 2,580 933 4059 II >10000 9,445 5,293 2,335 1,3039 IV & VI >10000 9,232 5,133 2,228 1,2239 V >10000 8,272 4,413 1,748 86312 II >10000 >10000 7,127 3,150 1,76212 IV & VI >10000 >10000 6,967 3,043 1,68212 V >10000 >10000 6,247 2,563 1,682




Actuator Air VolumeValve applications may need to determine the amount of air, gas or liquid to actuate an actuator to its rated travel. The first segment of Table 18 is the 2700A Actuator Air Chamber Volumes at initial travels and at final travel. The choice of final travel depends on the size of the valve trim. The required added air to actuate the actuator is the amount of air, of gas, to be added to the atmospheric pressure in the actuator and may be calculated from the following equation or found in the last four segments of Table 18.

Req'd Added Air to Actuate =(Actuator Volume) (Actuator Air Pressure)

(14.7) Std Ft3

Table 19 - Actuator Air Chamber Volume & Required Added Air to Actuate2700A Actuator Air Chamber Volume (Cubic Feet)

TravelActuatorSize 0” 0.625” 0.75” 1” 1.25” 1.5” 2” 2.75” 4”

9 0.035 0.046 0.048 0.05212 0.053 0.073 0.077 0.086 0.094 0.104 0.11916 0.076 0.109 0.116 0.132 0.146 0.167 0.19218 0.371 0.477 0.512 0.547 0.615 0.731

Required Added Air to Actuate at 18 PSIG (Standard Cubic Feet)TravelActuator

Size 0.625” 0.75” 1” 1.25” 1.5” 2” 2.75” 4”9 0.056 0.059 0.06412 0.089 0.094 0.105 0.115 0.128 0.14616 0.133 0.143 0.161 0.179 0.205 0.23518 0.584 0.627 0.669 0.754 0.895


Size 0.625” 0.75” 1” 1.25” 1.5” 2” 2.75” 4”9 0.075 0.078 0.08612 0.119 0.126 0.140 0.154 0.170 0.19516 0.178 0.190 0.215 0.239 0.273 0.31318 0.779 0.837 0.892 1.005 1.193


Size 0.625” 0.75” 1” 1.25” 1.5” 2” 2.75” 4”9 0.093 0.098 0.10712 0.149 0.157 0.175 0.192 0.213 0.24416 0.222 0.238 0.269 0.299 0.341 0.39118 0.974 1.046 1.115 1.256 1.491


Size 0.625” 0.75” 1” 1.25” 1.5” 2” 2.75” 4”9 0.112 0.117 0.12812 0.179 0.189 0.210 0.230 0.255 0.29216 0.267 0.285 0.322 0.359 0.410 0.46918 1.169 1.255 1.338 1.507 1.790



APPLICATION GUIDE FOR CAVITATION, FLASHING AND COMPRESSIBLE FLOW SERVICES

Valve applications involving cavitation, flashing and noise reduction of compressible flow require special sizing and application considerations and, in most cases, special trims are required. This guide discusses these phenomena with a definition, a list of possible countermeasures, instructions on application of Norriseal's 2700A Trims, and a technical discussion of the phenomena. Cavitation and flashing are in the "Liquid Flow" Section and compressible flow noise reduction is in the "Compressible Flow Noise" Section.

Liquid Flow

Cavitation and flashing applications require accurate prediction to determine when they occur and proper valve selection to supply the best trim for the application.

Cavitation

Cavitation DefinitionCavitation is a two stage phenomena with liquid flow. The first stage is the formation of vapor bubbles in the liquid as the fluid passes through the trim and the pressure is reduced below the fluid's vapor pressure. The second stage is the collapse of the vapor bubbles back to liquid as the fluid passes the vena contracta and the pressure recovers and increases above the vapor pressure. The collapsing bubbles are very destructive when they contact metal parts and the bubble collapse may produce high noise levels.

Cavitation Countermeasures

There are several ways to deal with cavitation.

Method 1: Cavitation avoidance: Cavitation can be avoided by selecting a valve style that has FL (rated) values greater than required for the application. This is an especially useful advantage of globe valves over ball and butterfly valves. Norriseal's options are the use of the CAV II that has a higher FL

value than the standard port and cage control trims.

Cavitation can also be avoided with the installation of an orifice plate downstream of the valve that shares the pressure drop. The valve's pressure drop is reduced to the point of avoiding damaging cavitation. The downstream orifice plate also should be sized to avoid damaging cavitation. This may not be suitable for applications with a wide flow range as the low flow condition may put the entire pressure drop on the valve.

Method 2: Cavitation Tolerant: Standard trim designs can tolerate mild cavitation applications. These applications will have increased flow noise from the mild cavitation but should not have damage from cavitation.

Method 3: Cavitation Containment: A trim design that allows cavitation to occur but in a harmless manner can be effective in preventing cavitation damage and reducing cavitation noise. Cavitation containment designs are limited to cavitation applications of moderate intensity.

Method 4: Cavitation Prevention: A trim design that takes the pressure drop in several steps or stages can avoid the formation of cavitation. These trim designs are more expensive than other methods but may be the only alternative in the more severe cases of cavitation. Graph 4 shows how a three stage trim can eliminate cavitation that would occur in a single stage trim. The total pressure drop is taken in three stages instead of one. Notice none of the vena contracta pressures of the three stage trim are below the vapor pressure.



Application of Norriseal Trims in Cavitation Service

Cavitation Avoidance: The Plug Control and Cage Control 2700A trims both have relatively high FL values and can avoid choked flow at significantly high pressure drops. The CAV II trim, with a higher FL

value, will avoid cavitation with a 10% higher pressure drop than the Plug or standard Cage Control Trims.

Cavitation Tolerant: All of our 2700A Cage Control Trims are tolerant to cavitation service where the FL (required) exceeds the FL (rated) and the inlet pressure is 50 psig or less for standard materials or 200 psig or less with stellited valve seat and plug's guide & seat. At this inlet pressure, the severity of cavitation will be small enough to use any Cage Control Trim in the flow down direction.

The unbalanced Plug Control Trims with tungsten carbide or ceramic materials can withstand cavitation up to an inlet pressure of 2000 psig. These trims will not reduce noise. Oversized bodies are recommended to avoid body erosion.

Cavitation Containment: The 2700A CAV II trims are appropriate where the FL

(required) exceeds .94 and the inlet pressure is 1000 psig or less and the pressure drop is 500 psi or less.

For a FL(required) between .90 and .94, cavitation will be avoided. Above a FL of .94, the flow will cavitate but the CAV II trims will not be damaged by cavitation in these conditions. See table 4 for FL

values of Norriseal trims.

The flow noise from cavitation will be reduced by the amount shown in Graph 3. Determine the Critical Pressure Drop Ratio by dividing the actual pressure drop by the critical pressure drop. Use the

Critical Pressure Drop Ratio to determine the SPL Attenuation Value from Graph 3. Subtract the SPL Attenuation Value from the predicted flow noise level for standard trims. Notice the CAV II trims will reduce flow noise even when there is no cavitation. The flow noise calculation for CAV II trim is automatic with Norriseal’s Valve Sizing Program.

The CAV II trim will make multiple small cavitation plumes that will not as readily cause erosion damage and will generate less noise than a trim with plug or cage port control. The CAV II trim is used only in the flow down direction.

Cavitation Prevention: Special trims with two or three stages can be designed for the 2700A valve to suit a particular application. These trims will cost significantly more than the other trims discussed but will be applicable in conditions beyond the others. Consult with Application Engineering for multiple stage applications.

Application Summary

If FL(required) is less than FL(rated):No special considerations are required.

If FL(required) is greater than FL (rated) and P1 is 50/200/2000 psig or less:Use any Cage Control Trim in the Flow down direction. If P1 is 50 psig or less or stellited valve seat, guide and cage if P1 is between 200 and 50 psig. Unbalanced Plug Control Trims with carbide or ceramic materials may be used up to a 2000 psig inlet pressure.

If FL (required) is between .90 and .94 and the standard 2700A Cage Control Trims have choked flow:Use the CAV II Trim in the flow down direction to avoid choked flow.

If FL (required) is greater than .94, P1 is 1000 psig or less and the pressure drop is 500 psig or less:



Use the CAV II Trim in the flow down direction.

If the application is outside of the above options:Consult with the Application Engineer.

The Cavitation Phenomena

FLUID AND PRESSURE PROFILE -A control valve creates a pressure drop in the fluid as it controls the flow rate. The profile of the fluid pressure, as it flows through the valve, is shown in Graph 1. The fluid accelerates as it takes a pressure drop through the valve's trim, It reaches its highest velocity just past the throttle point, at a point called the vena contracta. The fluid is at its lowest pressure and highest velocity at the vena contracta. Past the vena contracta the fluid decelerates and some of the pressure drop is recovered as the pressure increases. For globe valves, thepressure difference from the inlet pressure P1 to the vena contracta pressure PVC is about 125% of the P1 to P2 pressure drop. The pressure in the vena contracta is not of importance until it is lower than the fluid's vapor pressure. Then the fluid willquickly form vapor bubbles and, if the pressure increases above the vapor pressure, the vapor bubbles instantly collapse back to liquid. This is cavitation. It will occur when the vapor pressure, shown as "PV Cavitation" in Graph 1, is more than the vena contracta pressure but less than the outlet pressure, P2. When the Vapor pressure, shown as "PV

Liquid" in Graph 1, is less than the vena contracta pressure, there is full liquid flow with no cavitation.Cavitation in control valves can have four negative effects;

Restricts fluid flow Causes severe vibrations Erodes metal surfaces Generates high noise levels.

CHOKED FLOW AND INCIPIENT CAVITATION -The liquid flow rate will increase as the pressure drop increases. However, when cavitation vapor bubbles form in the vena contracta, the vapor bubbles will increasingly restrict the flow of liquid until the flow is fully choked with vapor. This condition is known as "choked flow" or "critical flow".

When the flow is fully choked, the flow rate does not increase when the pressure drop is increased. Graph 2 shows these flow relationships. The flow curve begins in the chart's lower left corner with fully liquid flow. The relationship of flow to P P1 2 is linear until cavitation begins to form at the point of incipient cavitation. As more cavitation forms, the more the flow curve bends until it is horizontal and fully choked with the flow not increasing with additional pressure drop.

The larger the FL factor, the greater the pressure drop that can be taken before choked flow occurs. Note in table 4 that ball and butterfly valves have a relatively low FL

and Norriseal's CAV II trim will produce higher flow rate without choking than standard Cage or Plug Control Trims.

The point of "Incipient Cavitation" can be predicted with the P incipient in the equation in the “CV Formulas for Liquid Flow” using the KC factor. Values for KC are shown in table 4. Cavitation will begin at the point of "Incipient Cavitation" and increase in intensity to the point of choked flow. Cavitation at point of "Incipient Cavitation" is not damaging and is almost undetectable. At some point between incipient and choked, the cavitation may damage most trim styles. The location of the "Damage" point varies with trim style and material. A larger KC is preferred so the incipient cavitation range to choked flow is as small as possible.

As the point of damaging cavitation is not easily defined, sizing and application



methods use the Critical Pressure Drop and the Required FL to rate trims for cavitation service. The KC value is not used for trim selection only flow noise prediction.

CAVITATION DAMAGE -Cavitation damage problems are more likely to occur with water flow as water has a well defined vapor pressure and the vapor bubble collapse is instantaneous. Hydro-carbon fluids have a less precise vapor pressure and are often a compound with several vapor pressures. Cavitation damage with hydro-carbon fluids is usually less severe than water as the bubble collapse is not as sudden and can be cushioned by other vapors. However the vibration and flow noise problems remain.

The fluid's inlet pressure is proportional to the amount of energy available to cause cavitation damage. Higher inlet pressureswill produce more intense and more damaging cavitation. The amount of cavitation is related to the degree the required FL exceeds the rated FL. As the required FL exceeds the rated FL, the amount of cavitation increases. A valve with a rated FL of .90 in an application requiring a FL of .96 will have more cavitation than an application requiring .92. There will be more cavitation but not more flow!

The generation and implosion of the vapor bubbles will cause vibration to the valve's Plug that may cause wear between the Plug and Cage or Guide and can cause Stems to break.

The implosion of the bubbles when near or on a metal surface can generate extremely high shock stresses in the metal surface that usually damages the metal with severe erosion of the metal. This phenomena, when severe, can destroy trims within hours! The generation and implosion of the vapor bubbles will cause

significantly elevated flow noise in addition to vibration.

The cavitation bubbles will form a vapor plume in the liquid. The larger the plume, the noisier the flow and the more likely it is to cause erosion damage. The size of the plume is dependent on trim style and severity of cavitation. The CAV II Trim with many small orifices will have significantly smaller vapor plumes with less noise and a reduced damage potential than a standard trim.

There is not much positive to say about cavitation. Valves improperly applied or without adequate cavitation protection can lead to early failure.

FLASHING

Flashing Definition -Flashing is a one stage phenomena somewhat similar to cavitation. The difference is the downstream pressure does not recover enough to be above the fluid's vapor pressure. The vapor bubbles in the liquid do not collapse and they remain in the fluid as vapor. Generally only part of the fluid vaporizes so the resulting flow downstream of the valve is two phase, vapor and liquid. Flashing is similar to cavitation in some respects but is not quite as severe. There are means to prevent or retard cavitation but not flashing! If the valves outlet pressure is below the vapor pressure, flashing will occur regardless of the valve's trim. When the Vapor pressure, shown as "PV Flashing" in Graph 1, is greater than the outlet pressure, there is flashing flow.

Flashing Countermeasures -There are several measures that should be made in flashing applications.

Body Material: The flashing process can cause body erosion that may reduce the body's wall thickness to less than required by codes. The fluid in the valve body



downstream of the trim is highly turbulent as a two phase flow mixture of vapor and liquid. The turbulent mixture can easily erode body materials, such as carbon steel, that may not have sufficient erosion resistance.

Trim Selection: Avoid the use of Balanced Plug Control Trim in flashing applications as the flashing process may make the trim unstable. High pressure drops in flashing service is best served with a cage control trim with multiple small orifices, CAV II, that reduce the trim's vibration from the fluid's turbulence

APPLICATION OF NORRISEAL VALVES IN FLASHING SERVICE

Body Material: The flashing process can cause body erosion that may reduce the body's wall thickness to less than required by codes. Severe flashing service should have stainless steel or Chrome-Moly (WC6) bodies, Carbon steel may not be suitable.

Trim Selection: If the pressure drop is 50 PSI or less, standard Cage Control Trim is suitable. Plug control Trim is not recommended for flashing service. For pressure drops greater than 50 psi, CAV II Trim or Unbalanced Plug Control Trims with tungsten carbide or ceramic are recommended.

THE FLASHING PHENOMENA

Liquids in flashing service undergo a transformation from all liquid flow to two phase flow of flashed vapor and the remaining liquid. The liquid will flash until thermodynamic equilibrium is achieved with the vapor fully saturated. Often the majority of the volume will be vapor and some of the remaining liquid will be suspended as droplets in the vapor. As the velocity of the vapor can reach as high

as sonic velocity, the liquid droplets can cause severe erosion the valve body and the downstream pipe. The flashing process is highly turbulent with the liquid impacting the valve trim at high velocity. The effects of the turbulent flashing liquid can cause trim instability if it impacts the control surfaces of the Plug. For this reason, Plug Control Trim is not suitable for flashing service. The CAV II Cage will distribute the flashing process into a large number of small jets reducing the total turbulence and reducing the vibration effects on the Plug and the erosion effects to the body. Often flashing service will be in the flow down direction through an angle style body. The object is the get the flashing through the valve without significant contact with the body. As Norriseal does not have a angle body, our best solution is flow down through the CAV II using the trim's small holes to reduce the total turbulence and protect the body. Flashing service with pressure drops less than 50 PSI will have less severe turbulence so the standard Cage Control Trims with flow down will be suitable.

LIQUID FLOW VELOCITY - BODY MATERIAL

High liquid flow velocities in valve bodies can cause metal erosion even though there may be no cavitation or flashing. Liquid flow velocity in valve bodies should be limited to the velocities shown in Table 6 to avoid flow erosion. The body's flow velocity, for liquid flow, can be calculated. The body flow velocity at the smallest flow passage, usually the body inlet or outlet, should not exceed the velocities in Table 20.

Table 20LIQUID FLOW VELOCITY LIMITS

Application LimitsPressure Drop InfrequentBody

Material > 500 PSI < 500 PSI < 2% of time

Carbon Steel 30 Ft/Sec 40 Ft/Sec 50 Ft/SecStainless or WC6 (Cr-Mo)

45 Ft/Sec 60 Ft/Sec 90 Ft/Sec



COMPRESSIBLE FLOW NOISE

Compressible Flow Noise Discussion -Flow noise from compressible flow is a major application consideration. The flow noise must be accurately predicted and the appropriate valve trim chosen to meet the customers requirements and assure good valve operation.

Compressible flow noise is generated by fluid turbulence, the more turbulence the more noise. Fluid turbulence is increased by higher flow rates and by a higher fluid pressure drop through valve trim. As the valve's pressure drop reaches the critical condition and the speed of sound is reached in the flow stream's vena contracta, shock waves are produced that increases the noise level above that produced by turbulence alone.

Compressible Flow Noise Countermeasures -There are several methods to reduce compressible flow noise.

Multiple Orifice Trims: A trim with a high number of small flow orifices will produce less flow noise than a trim of equal flow capacity with either four or one flow orifices. The small holes produce smaller flow jets that generate proportionally less noise as the small holes are less efficient in converting mechanical power to acoustical power than large holes. Norriseal's DB I and DB II trims have multiple small orifices and are significant quieter than standard plug or cage control trims.

Backpressure Orifice: The flow noise increases rapidly with increased pressure drop especially when the critical pressure drop is exceeded. However if the total pressure drop can be shared by two devices, the flow noise can be significantly reduced. This can be accomplished with a fixed orifice plate downstream of a

control valve. At maximum flow the valve and orifice plate can have about the same pressure drop and generate less noise than taking the total drop across the valve alone. At lower flow rates, the noise from flow through the valve will probably be less than at full flow even though the valve's pressure drop increases as the pressure drop acrossthe fixed orifice plate decreases. The backpressure orifice plate may be in the form of a cylindrical diffuser. The backpressure orifice device also should be sized for flow noise.

Two Stage Trim: A two stage valve will reduce flow noise beyond the noise reduction of the DB I and DB II trims. The two stage trim is similar to two DB II trims one inside of the other. The inner stage takes the majority of the pressure drop with the outer stage acting as a diffuser to reduce flow turbulence.

APPLICATION OF NORRISEAL TRIMS IN COMPRESSIBLE FLOW APPLICATIONS

Low noise considerations should be applied when the predicted noise level exceeds the customers requirement or when the noise level exceed 110 dBA. Flow noise in excess of 110 dBA can permanently damage a person’s hearing and the noise induced vibrations can damage the valve’s trim and instrumentation mounted on the valve.

Standard Trims: Calculate the flow noise for the specified conditions. The standard Plug Control, flow up, or the Cage Control, flow down, may meet the customer's noise requirements or our 110 dBA limit. In this case no further measures are required providing the downstream flow velocity is not excessive.

DB I and DB II Multiple Orifice Trims: The DB I and DB II trims will reduce compressible flow noise in the flow up configuration.



Determine the predicted flow noise for standard cage control trim. Calculate the valve's pressure ratio by dividing the upstream pressure by the downstream pressure, both psia, and determine the "Noise Attenuation Value" from Graph 5. To determine the aerodynamic flow noise with DB I and DB II trims, subtract the "Noise Attenuation Value" from the predicted flow noise for standard cage control trim. Graph 5 shows noise attenuation for both the DB I slotted cage and the DB II drilled hole cage. Noise attenuation for the DB I cage is less than the DB II but the cost of a DB I is also less than the DB II. Choose the cage style appropriate for the application. The DB I cage is not available in trim sizes larger than 4". The flow noise calculation for DB I and DB II trim is automatic with Norriseal’s Valve Sizing Program.

Compressible Flow Velocity Limits: If flow noise is being controlled, the flow velocity in the valve body and downstream piping should be limited to 1/3 sonic velocity for DB II and 1/2 sonic velocity for DB I trims. Higher velocities will generate significant flow noise in the pipe even though a low noise trim is installed. Applications with low outlet pressures can readily have high downstream velocities. Sonic velocity at the valve's outlet can produce flow noise as high as 135 dBA as the shock waves from the sonic velocity will propagate downstream as the pipe acts as a megaphone! The body's flow velocity, for compressible flow, can be calculated using the body outlet diameter from Table 5.

Two Stage Trims and Backpressure Orifices: Two stage trims and backpressure orifices require special analyses and designs not available as standard. The use of two stage trims and downstream orifices may reduce the flow noise an additional 10 dBA beyond the reduction of the DB II Trim. Consult

Norriseal’s Application Engineering for applications with DB II that have predicted noise values above the required limit.

THE COMPRESSIBLE FLOW NOISE PHENOMENA

A control valve's purpose is to create a pressure drop, the pressure drop creates fluid turbulence and the turbulence generates flow noise. The resultant flow noise is inevitable but can be minimized by trim and valve selection.

Flow noise produced by a valve will be transmitted through the wall of the downstream pipe. Very little noise will come through the valve body wall as the area of the pipe's wall is larger than the pipe's wall thickness.

High flow noise from compressible flow presents two problems. Mechanical vibrations from excessive noise levels can quickly destroy the trim and also may damage accessories mounted on the valve's actuator. The major problem from high flow noise is hearing damage to people in the vicinity of the valve. OSHA has established noise limits that vary from 115 dBA to 85 dBA depending on the length of daily exposure. the 115 dBA is for 15 minutes exposure and 85 dBA is for an 8 hour exposure. The usual requirement is 85 dBA as it is difficult to limit a person's exposure. Ear protection can help protect a person's hearing, but with today's legal liability rulings, the owner of the process is liable for people's hearing damage even if they exceed posted exposure times and do not use provided ear protection. We should be concerned if the predicted noise level exceeds 110 dBA even if the customer does not impose a limit. Flow noise exceeding 110 dBA, for any significant time can damage the valve trim and accessories.

Norriseal uses both ISA's CV formulas from ISA 75.01 and ISA's Control Valve



Aerodynamic Noise Prediction formulas from ISA 75.07.01. ISA 75.07.01 was published in 1989 and has become recognized as the best compressible flow noise prediction method. The major control valve companies, Fisher and Masoneilan, had developed, in the 1960's, empirical noise prediction techniques based on laboratory test data. Formulas

were written to fit the test data. In the 1980's ISA developed a theoretical noise prediction method, with the combined input from many valve companies, that is more accurate than the previous empirical methods. The ISA noise prediction method applies only to standard plug or cage control trims. Low flow noise designs require an additional factor to be subtracted from the ISA value.



Table 21 - Flow Coefficients, CV, 2200/2220 Globe Body, Modified Percentage &Quick Opening, Unbalanced Plug Control Trims, Flow Up

Flow Coefficient (CV)Valve Opening - Percent of Total Travel

Modified PercentageQuick Open

BodySize

TrimSize

10 20 30 40 50 60 70 80 90 100 1000.250” .284 .506 .657 .767 .875 .989 1.10 1.20 1.32 1.43 1.680.375” .311 .621 .942 1.28 1.64 2.07 2.51 2.93 3.35 3.70 3.82

1” 0.500” .557 1.11 1.68 2.26 2.92 3.62 4.30 4.98 5.43 5.60 5.600.750” .752 1.57 2.43 3.42 4.58 6.08 7.93 9.71 10.6 11.0 11.61.000” .983 2.01 3.40 6.12 8.90 11.7 13.5 14.4 15.1 15.4 15.40.250” .284 .506 .657 .767 .875 .989 1.10 1.20 1.32 1.43 1.680.375” .311 .621 .942 1.28 1.64 2.07 2.51 2.93 3.35 3.70 3.75

2” 0.500” .592 1.17 1.76 2.34 2.95 3.70 4.57 5.50 5.95 6.08 6.080.750” .882 1.76 2.76 3.82 5.05 6.57 8.49 10.8 12.2 12.9 13.01.000” 1.01 2.02 3.08 4.67 6.96 10.3 13.7 15.4 16.7 17.1 23.0

Table 22 - Flow Coefficients, CV, 2275A Globe and Angle Bodies, Modified Percentage & Quick Opening, Unbalanced Plug Control Trims, Flow Up



Globe Body Size

Trim Size

10 20 30 40 50 60 70 80 90 100 1000.062” .016 .026 .033 .038 .043 .048 .058 .072 .086 .100 .0960.125” .050 .073 .088 .111 .155 .258 .324 .367 .389 .407 .446

1’ 0.250” .487 .588 .617 .693 .802 .940 1.08 1.22 1.33 1.36 1.400.375” .724 .901 1.04 1.41 2.27 2.74 3.05 3.25 3.38 3.45 3.510.500” .887 1.13 1.82 3.45 4.24 4.70 4.98 5.14 5.18 5.22 5.90



AngleBodySize

TrimSize

10 20 30 40 50 60 70 80 90 100 1000.062” .010 .017 .025 .034 .045 .055 .065 .077 .092 .109 .1090.125” .031 .046 .068 .133 .204 .269 .328 .377 .402 .415 .421

1’ 0.250” .505 .579 .612 .659 .753 .885 1.01 1.14 1.27 1.34 1.380.375” .707 .978 1.26 1.53 2.00 2.48 2.92 3.23 3.44 3.52 3.590.500” .725 1.15 1.98 3.05 4.10 5.11 5.70 5.93 6.08 6.18 6.20



Table 23 - Flow Coefficients, CV, 2400/2420 Globe Body, Modified Percent,Unbalanced Plug Control Trims, Flow Up


BodySize

TrimSize

10 20 30 40 50 60 70 80 90 1000.250” .284 .506 .657 .767 .875 .989 1.10 1.20 1.32 1.430.375” .311 .621 .942 1.28 1.64 2.07 2.51 2.93 3.35 3.700.500” .592 1.17 1.76 2.34 2.95 3.70 4.57 5.50 5.95 6.080.750” .882 1.76 2.76 3.82 5.05 6.57 8.49 10.8 12.2 12.91.000” 1.05 2.10 3.21 4.86 7.24 10.7 14.3 16.0 17.4 17.81.250” 1.60 3.17 6.42 9.78 13.2 16.6 20.1 23.8 27.1 29.81.500” 2.02 3.51 7.60 12.0 16.3 20.7 24.4 27.8 31.0 34.0

2”

1.750” 2.14 3.81 8.09 12.6 16.9 21.2 25.7 30.5 34.6 38.1

Table 24 - Flow Coefficients, CV, 2700/2720A/E Globe Body,Balanced Quick Opening Cage Control Trims, Flow Down


BodySize

TrimSize

10 20 30 40 50 60 70 80 90 1001” 1” .675 2.20 6.68 11.0 15.1 17.8 19.7 20.6 21.1 21.6

1” .675 2.20 6.90 12.5 17.7 23.0 28.2 33.2 36.9 39.11.5”1.5” 1.06 6.02 15.2 24.5 33.4 40.0 43.4 45.6 46.9 47.51” .675 2.20 6.90 12.5 17.8 24.4 31.0 37.2 41.7 44.6

1.5” 1.06 6.02 16.5 26.7 37.2 47.5 56.4 62.7 66.7 69.42”2” 2.03 9.34 24.8 40.5 52.8 59.4 64.2 67.6 69.8 71.31” 6.75 2.20 6.90 12.5 17.8 24.4 31.0 37.2 41.7 44.6

1.5” 1.06 6.02 16.5 26.7 39.9 53.1 61.4 67.0 70.9 73.72” 2.03 9.34 25.4 41.6 57.5 69.6 78.6 83.6 85.9 88.1

3”

3” 4.63 14.5 37.2 65.4 86.0 100 109 114 117 1191” .675 2.20 6.90 12.5 17.8 24.4 31.0 37.2 41.7 44.6

1.5” 1.06 6.02 16.5 26.7 39.9 53.1 66.5 75.2 81.0 84.92” 2.03 11.9 28.2 49.8 70.6 85.3 94.9 102 106 1103” 5.47 21.6 48.1 77.1 104 124 139 148 153 155

4”

4” 12.4 40.8 85.6 128 159 179 193 199 201 2034” 14.7 50.2 108 165 220 258 282 295 302 3056”6” 37.9 114 210 287 344 384 406 415 419 4226” 37.9 119 223 325 430 500 537 561 573 5788”8” 95.9 257 434 596 713 777 818 833 837 841

Table 25 - Flow Coefficients, CV,2700/2720A/E Globe Body,



Balanced Linear Cage Control Trims, Flow DownFlow Coefficient (CV)

Valve Opening - Percent of Total TravelBodySize

TrimSize

10 20 30 40 50 60 70 80 90 1001” 1” .355 1.01 2.48 5.46 8.43 11.3 14.3 16.9 18.6 19.6

1” .355 1.01 2.48 5.46 8.50 12.4 16.4 20.7 25.0 29.21.5”1.5” .906 3.26 7.35 13.1 20.2 27.7 34.5 39.8 43.5 45.51” .355 1.01 2.48 5.46 8.50 12.4 16.4 20.9 25.6 30.2

1.5” .906 3.26 7.35 13.1 20.2 28.8 37.2 46.0 54.8 61.32”2” 1.51 4.87 11.0 20.3 30.9 41.5 50.2 57.0 61.4 64.81” .355 1.01 2.48 5.46 8.50 12.5 14.7 22.6 27.8 33.1

1.5” .906 3.26 7.35 13.1 20.2 29.8 40.5 50.9 58.4 63.02” 1.51 4.87 11.9 22.8 34.4 46.1 57.6 69.0 76.9 81.5

3”

3” 3.23 8.30 19.6 37.6 55.8 73.7 88.9 101 110 1171” .355 1.01 2.48 5.46 8.50 12.4 17.4 22.6 27.8 33.1

1.5” .906 3.26 7.35 13.1 20.2 30.4 42.4 54.2 65.5 72.12” 1.51 7.61 14.6 25.6 39.9 54.6 67.8 78.2 87.5 94.13” 3.60 12.4 25.7 44.3 64.9 85.8 106 122 135 145

4”

4” 8.57 21.2 42.7 68.5 94.0 120 145 168 184 1954” 11.7 31.5 66.8 103 139 175 210 246 271 2846”6” 19.6 55.8 104 152 200 248 296 339 369 3916” 24.8 75.2 140 203 266 331 393 457 502 5238”8” 55.3 125 224 324 422 521 618 705 752 790

Table 26 - Flow Coefficients, CV, 2700/2720A/E Globe Body,Balanced Equal Percentage Cage Control Trims, Flow Down


BodySize

TrimSize

10 20 30 40 50 60 70 80 90 1001” 1” .308 .565 1.21 2.63 4.83 8.16 12.4 15.5 17.8 18.9

1” .308 .565 1.21 2.63 5.06 8.40 13.0 17.9 22.7 27.31.5”1.5” .400 .813 2.36 4.86 8.49 15.1 22.7 30.3 35.5 39.21” .308 .565 1.39 3.02 5.26 8.81 13.4 18.9 24.4 29.9

1.5” .400 .813 2.41 5.24 9.45 17.1 27.9 39.2 49.7 57.52”2” .643 2.20 4.82 9.29 15.6 25.9 39.5 53.0 58.5 62.01” .308 .565 1.39 3.02 5.26 8.81 14.6 20.3 26.3 32.2

1.5” .400 .813 2.41 5.24 9.45 17.1 28.0 39.3 50.7 61.72” .643 2.20 4.82 9.29 15.6 25.9 39.5 55.4 68.0 77.2

3”

3” .906 3.31 7.72 15.4 27.7 46.8 70.1 93.7 108 1161” .308 .565 1.39 3.02 5.26 8.81 14.6 20.3 26.3 32.2

1.5” .400 .813 2.41 5.24 9.45 17.1 28.9 42.4 55.3 63.82” .643 2.20 4.82 9.29 15.6 25.9 39.5 55.4 70.9 82.13” .906 4.03 9.25 17.3 29.2 49.0 77.0 106 131 142

4”

4” 2.83 9.09 19.5 33.9 52.0 79.8 119 159 185 1954” 5.34 9.84 18.5 38.6 65.6 107 155 206 249 2696”6” 6.84 19.6 40.1 69.6 107 163 244 325 360 3786” 11.8 23.1 43.2 78.8 139 223 310 399 472 5088”8” 18.1 44.1 86.9 143 221 346 494 642 728 756



Table 27 - Flow Coefficients, CV, 2700/2720A/E Globe Body,Balanced DB I Noise Abatement Cage Control Trims, Flow Up


BodySize

TrimSize

10 20 30 40 50 60 70 80 90 1001” 1” .480 1.85 5.25 8.61 11.9 14.6 16.6 17.9 18.6 18.8

1” .480 1.85 5.51 9.33 13.0 17.1 21.0 24.7 27.5 29.81.5”1.5” 1.13 5.21 12.7 20.0 27.4 34.1 38.3 40.8 42.4 43.91” .480 1.85 5.51 9.33 13.0 17.1 21.4 26.0 29.9 32.3

1.5” 1.13 5.21 12.7 20.0 27.4 34.5 41.1 47.2 51.5 54.82”2” 1.78 7.50 18.7 29.6 40.7 49.9 55.7 59.1 61.1 61.91” .480 1.85 5.51 9.33 13.2 17.3 22.0 27.4 32.0 35.4

1.5” 1.13 5.21 12.7 20.0 28.6 38.5 49.1 56.2 61.5 65.82” 1.78 7.5 18.7 32 44.5 56.2 66.6 75.1 81.3 85.3

3”

3” 3.04 12.7 30.2 49.6 67.6 82.4 93.5 102 108 1121” .480 1.85 5.51 9.33 13.2 17.3 22.0 27.4 32.0 35.4

1.5” 1.13 5.21 12.7 20.0 29.4 39.7 49.4 57.8 65.1 70.32” 1.78 7.5 18.7 32.0 44.8 57.6 69.7 80.5 89.4 95.83” 4.25 15.8 33.9 52.4 71.4 89.8 108 124 137 147

4”

4” 10.4 38.9 77.5 111 134 150 160 166 172 1786” 4” 9.18 36.1 72.4 108 145 181 215 237 251 262

Table 28 - Flow Coefficients, CV, 2700/2720A/E Globe Body,Balanced DB II Noise Abatement Cage Control Trims, Flow Up


BodySize

TrimSize

10 20 30 40 50 60 70 80 90 1001” 1” .475 1.59 4.71 7.80 10.9 14.0 16.1 17.5 18.2 18.6

1” .475 1.59 4.91 8.13 11.5 14.8 18.1 21.5 24.8 28.21.5”1.5” 1.04 3.46 9.93 16.3 22.2 27.4 32.2 36.2 39.7 42.01” .475 1.59 4.91 8.40 11.8 15.3 18.8 22.3 25.7 29.1

1.5” 1.04 3.46 9.93 16.3 22.2 27.7 33.3 38.9 44.5 49.92”2” 1.60 7.33 18.0 28.6 39.2 47.8 53.6 57.5 60.1 61.51” .475 1.59 4.91 8.40 11.8 15.3 18.8 22.4 26.8 31.6

1.5” 1.04 3.46 9.93 16.3 22.2 28.2 34.8 42.0 49.4 56.62” 1.60 7.33 18.0 28.6 39.2 49.4 59.8 70.5 78.7 83.8

3”

3” 1.71 9.93 24.5 38.8 53.3 66.0 77.5 87.2 94.6 1001” .475 1.59 4.91 8.40 11.8 15.3 18.8 22.4 26.8 31.6

1.5” 1.04 3.46 9.93 16.3 22.5 29.1 36.5 44.7 52.8 60.92” 1.60 7.33 18.0 28.6 39.3 50.1 60.8 71.7 82.3 92.93” 4.47 13.7 27.2 41.2 55.8 70.0 84.2 96.9 107 115

4”

4” 7.01 28.1 50.4 72.9 94.2 114 129 141 151 1602” 9.09 32.4 60.4 87.4 115 142 170 195 213 2246”3” 23.9 67.3 117 166 215 258 292 318 337 3514” 24.9 69.2 118 166 220 271 317 357 385 4058"6” 47.3 131 220 305 389 462 524 574 611 644



Table 29 - Flow Coefficients, CV, 2700/2720A/E Globe Body,Balanced CAVII Cavitation Cage Control Trims, Flow Down


BodySize

TrimSize

10 20 30 40 50 60 70 80 90 1001” 1” .453 1.18 4.12 7.12 10.1 13.2 15.8 16.9 17.7 18.5

1” .453 1.18 4.59 8.45 12.6 16.5 20.2 23.5 26.1 27.91.5”1.5” .890 2.67 8.58 14.5 20.5 26.7 31.5 35.2 38.0 40.21” .453 1.18 4.73 8.95 13.2 17.4 21.3 25.0 28.3 31.0

1.5” .890 2.67 9.00 15.7 22.2 28.8 35.3 41.2 45.7 49.32”2” 1.55 7.69 17.9 28.2 38.6 46.2 51.9 55.8 58.7 61.31” .453 1.18 4.73 8.95 13.2 17.4 21.3 25.0 28.3 31.0

1.5” .890 2.93 10.0 17.0 23.8 30.7 37.0 42.7 47.6 51.92” 1.55 7.70 18.8 30.0 41.2 51.8 58.8 64.0 68.6 73.0

3”

3” 1.66 9.88 23.7 37.4 51.0 63.1 73.0 80.9 87.0 91.71” .453 1.18 4.73 8.95 13.2 17.4 21.3 25.0 28.3 31.0

1.5” .890 2.93 10.0 17.0 23.8 30.7 37.0 42.7 47.6 51.92” 1.55 7.70 20.7 32.1 42.7 52.6 60.7 67.0 72.6 76.73” 4.04 15.7 30.6 45.1 58.2 69.7 80.0 88.6 96.0 104

4”

4” 6.40 26.8 48.3 69.9 88.7 103 115 126 136 1464” 8.82 31.4 55.9 80.0 105 129 150 166 178 1866”6” 21.8 66.9 115 163 207 239 266 289 309 3286” 28.2 77.2 127 176 227 274 320 353 375 3908”8” 45.4 128 213 297 371 428 478 523 565 603

Table 30 - Flow Coefficients, CV, 2700/2720A/E Globe Body, Modified Percent,Balanced Plug Control Trims, Flow Up


BodySize

TrimSize

10 20 30 40 50 60 70 80 90 1001” 1” 1.17 2.29 3.82 6.65 10.9 15.2 17.7 19.3 20.2 20.5

1” 1.17 2.29 4.29 7.75 13.2 19.1 25.2 30.5 34.1 36.01.5”1.5” 3.13 6.06 9.68 17.7 28.8 40.0 47.2 51.6 54.0 54.81” 1.17 2.29 4.29 7.75 13.2 19.6 25.7 31.5 35.1 37.1

1.5” 5.03 7.67 9.53 12.9 18.4 24.9 33.6 44.0 53.4 59.52”2” 5.01 11.0 20.3 33.8 48.9 61.4 67.2 69.5 70.8 71.61” 1.17 2.29 4.29 7.75 13.2 19.6 25.7 31.5 35.1 37.1

1.5” 5.03 7.67 9.53 12.9 18.4 26.2 35.6 46.2 57.0 65.12” 5.01 9.85 16.6 30.6 47.2 62.9 77.0 88.8 96.4 101

3”

3” 6.15 14.9 27.7 52.5 80.3 104 118 124 128 1291” 1.17 2.29 4.29 7.75 13.2 19.6 25.7 31.5 35.1 37.1

1.5” 5.03 7.67 9.53 12.9 18.4 26.2 37.9 50.6 62.1 67.42” 6.2 11.5 20.9 37.1 53.1 70.3 82.1 93.8 104 1103” 14.8 29.0 44.1 59.1 80.6 111 135 151 166 172

4”

4” 14.8 23.2 38.3 71.5 114 148 177 196 207 2112” 6.2 11.5 20.9 37.1 53.1 70.3 82.1 93.8 104 1103” 14.8 29.0 44.1 67.2 96.6 126 155 181 195 2104” 15.4 31.3 57.5 101 145 190 234 272 294 316

6”

6” 19.8 40.1 76.7 128 192 252 312 352 378 4004” 15.4 31.3 66.6 117 168 220 271 315 340 3666” 26.8 54.2 99.7 175 252 329 406 471 510 5488”8” 36.3 75.2 138 242 375 522 641 723 780 805



Table 31 - Flow Coefficients, CV, 2700/2720A/E Globe Body, Quick Opening,Balanced Plug Control Trims, Flow Up


BodySize

TrimSize

10 20 30 40 50 60 70 80 90 1001” 1” 8.83 14.0 17.4 19.2 20.2 20.9 21.2 21.5 21.7 21.9

1” 10.9 20.6 27.1 31.7 34.9 37.3 38.9 39.8 40.3 40.51.5”1.5” 13.2 26.4 37.2 44.3 49.1 52.4 54.2 54.8 55.3 55.91” 10.9 20.6 27.9 33.8 38.2 41.5 43.6 45.1 45.8 46.2

1.5” 18.4 33.4 46.9 56.5 60.9 62.3 63.7 64.4 64.6 65.02”2” 19.6 38.7 55.2 62.7 65.6 67.5 68.8 70.0 71.3 72.81” 10.9 20.6 27.9 33.8 38.2 41.5 43.6 45.1 45.8 46.2

1.5” 18.4 33.4 46.9 57.7 66.9 73.9 77.3 79.9 81.4 81.92” 19.6 38.7 59.9 74.5 88.3 97.0 100 103 104 105

3”

3” 27.5 54.5 81.8 102 115 122 126 127 129 1301” 10.9 20.6 27.9 33.8 38.2 41.5 43.6 45.1 45.8 46.2

1.5” 18.4 33.4 51.1 63.7 70.5 78.1 83.2 87.7 90.5 92.52” 26.8 45.7 64.5 77.8 92.3 101 107 114 119 1223” 27.5 55.9 93.5 131 153 168 178 182 186 187

4”

4” 30.4 64.5 103 142 175 195 204 210 212 2132” 26.8 49.1 72.2 90.8 106 116 123 128 130 1323” 27.5 55.9 103 149 180 199 212 219 225 2294” 55.0 111 166 221 270 298 312 316 318 320

6”

6” 55.2 117 189 271 333 374 406 427 440 4444” 55.0 111 166 221 277 321 345 357 363 3696” 75.7 160 259 372 457 513 557 586 604 6098”8” 90.3 217 354 505 631 725 797 841 872 885

Table 32 - Flow Coefficients, CV, 2700/2720A/E Globe Body, Modified Percent, Unbalanced Plug Control Trims, Flow Up


BodySize

TrimSize

10 20 30 40 50 60 70 80 90 1000.250” .284 .506 .657 .767 .875 .989 1.10 1.20 1.32 1.430.375” .311 .621 .942 1.28 1.64 2.07 2.51 2.93 3.35 3.700.500” .557 1.11 1.68 2.26 2.92 3.62 4.30 4.98 5.43 5.600.750” .752 1.57 2.43 3.42 4.58 6.08 7.93 9.71 10.6 11.0

1”

1.000” .983 2.01 3.40 6.12 8.90 11.7 13.5 14.4 15.1 15.40.250” .284 .506 .657 .767 .875 .989 1.10 1.20 1.32 1.430.375” .311 .621 .942 1.28 1.64 2.07 2.51 2.93 3.35 3.700.500” .592 1.17 1.76 2.34 2.95 3.70 4.57 5.50 5.95 6.080.750” .882 1.76 2.76 3.82 5.05 6.57 8.49 10.8 12.2 12.9

1.5”

1.000” 1.01 2.02 3.08 4.67 6.96 10.0 13.0 14.7 15.5 16.30.250” .284 .506 .657 .767 .875 .989 1.10 1.20 1.32 1.430.375” .311 .621 .942 1.28 1.64 2.07 2.51 2.93 3.35 3.700.500” .592 1.17 1.76 2.34 2.95 3.70 4.57 5.50 5.95 6.080.750” .882 1.76 2.76 3.82 5.53 6.57 8.49 10.8 15.0 12.9

2”

1.000” .964 1.92 3.14 5.07 9.68 11.9 14.9 17.2 19.3 20.90.250” .284 .506 .657 .767 .875 .989 1.10 1.20 1.32 1.430.375” .311 .621 .942 1.28 1.64 2.07 2.51 2.93 3.35 3.700.500” .592 1.17 1.76 2.34 2.95 3.70 4.57 5.50 5.95 6.080.750” .882 1.76 2.76 3.82 5.53 6.57 8.49 10.8 15.0 16.2

3” & 4”

1.000” .964 1.92 3.14 5.07 9.68 11.9 14.9 17.2 19.3 20.9








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