ANSI ISA-75-11-01 (2013)E

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AMERICANNATIONALSTANDARD

ANSI/ISA-75.11.01-2013

Inherent Flow Characteristicand Rangeability of

Control Valves

Approved 30 January 2013

ded by IHS Sold to:CCI AG, 01972856Not for Resale,2013/8/16 15:30:27 GMTeproduction or networking permitted without license from I HS

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Preface

This preface, as well as all footnotes and annexes, is included for information purposes and isnot part of ANSI/ISA-75.11.01-2013.

This document has been prepared as part of the service of the International Society ofAutomation toward a goal of uni formity in the field of ins trumentation. To be of real value, thisdocument should not be static but should be subject to periodic review. Toward this end, theSociety welcomes all comments and criticisms and asks that they be addressed to the Secretary,Standards and Practices Board; ISA; 67 Alexander Drive; P. O. Box 12277; Research TrianglePark, NC 27709; Telephone (919) 549-8411; Fax (919) 549-8288; E-mail: [email protected].

The ISA Standards and Practices Department is aware of the growing need for attention to themetric system of units in general, and the International System of Units (SI) in particular, in thepreparation of instrumentation standards. The Department is further aware of the benefits to USAusers of ISA standards of incorporating suitable references to the SI (and the metric system) intheir business and professional dealings with other countries. Toward this end, this Departmentwill endeavor to introduce SI-acceptable metric units in all new and revised standards,recommended practices, and technical reports to the greatest extent possible. Standard for Use

of the International System of Units (SI): The Modern Metric System , published by the AmericanSociety for Testing & Materials as IEEE/ASTM SI 10-97, and future revisions, will be thereference guide for definitions, symbols, abbreviations, and conversion factors.

It is the policy of ISA to encourage and welcome the participation of all concerned individualsand interests in the development of ISA standards, recommended practices, and technicalreports. Participation in the ISA standards-making process by an individual in no way constitutesendorsement by the employer of that individual, of ISA, or of any of the standards, recommendedpractices, and technical reports that ISA develops.

CAUTION ISA DOES NOT TAKE ANY POSITION WITH RESPECT TO THE EXISTENCE ORVALIDITY OF ANY PATENT RIGHTS ASSERTED IN CONNECTION WITH THIS DOCUMENT,AND ISA DISCLAIMS LIABILITY FOR THE INFRINGEMENT OF ANY PATENT RESULTING

FROM THE USE OF THIS DOCUMENT. USERS ARE ADVISED THAT DETERMINATION OFTHE VALIDITY OF ANY PATENT RIGHTS, AND THE RISK OF INFRINGEMENT OF SUCHRIGHTS, IS ENTIRELY THEIR OWN RESPONSIBILITY.

PURSUANT TO ISAS PATENT POLICY, ONE OR MORE PATENT HOLDERS OR PATENTAPPLICANTS MAY HAVE DISCLOSED PATENTS THAT COULD BE INFRINGED BY USE OFTHIS DOCUMENT AND EXECUTED A LETTER OF ASSURANCE COMMITTING TO THEGRANTING OF A LICENSE ON A WORLDWIDE, NON-DISCRIMINATORY BASIS, WITH AFAIR AND REASONABLE ROYALTY RATE AND FAIR AND REASONABLE TERMS ANDCONDITIONS. FOR MORE INFORMATION ON SUCH DISCLOSURES AND LETTERS OFASSURANCE, CONTACT ISA OR VISIT WWW.ISA.ORG/STANDARDSPATENTS.

OTHER PATENTS OR PATENT CLAIMS MAY EXIST FOR WHICH A DISCLOSURE ORLETTER OF ASSURANCE HAS NOT BEEN RECEIVED. ISA IS NOT RESPONSIBLE FOR

IDENTIFYING PATENTS OR PATENT APPLICATIONS FOR WHICH A LICENSE MAY BEREQUIRED, FOR CONDUCTING INQUIRIES INTO THE LEGAL VALIDITY OR SCOPE OFPATENTS, OR DETERMINING WHETHER ANY LICENSING TERMS OR CONDITIONSPROVIDED IN CONNECTION WITH SUBMISSION OF A LETTER OF ASSURANCE, IF ANY,OR IN ANY LICENSING AGREEMENTS ARE REASONABLE OR NON-DISCRIMINATORY.

ISA REQUESTS THAT ANYONE REVIEWING THIS DOCUMENT WHO IS AWARE OF ANYPATENTS THAT MAY IMPACT IMPLEMENTATION OF THE DOCUMENT NOTIFY THE ISASTANDARDS AND PRACTICES DEPARTMENT OF THE PATENT AND ITS OWNER.


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ADDITIONALLY, THE USE OF THIS DOCUMENT MAY INVOLVE HAZARDOUS MATERIALS,OPERATIONS OR EQUIPMENT. THE DOCUMENT CANNOT ANTICIPATE ALL POSSIBLEAPPLICATIONS OR ADDRESS ALL POSSIBLE SAFETY ISSUES ASSOCIATED WITH USE INHAZARDOUS CONDITIONS. THE USER OF THIS DOCUMENT MUST EXERCISE SOUNDPROFESSIONAL JUDGMENT CONCERNING ITS USE AND APPLICABILITY UNDER THEUSERS PARTICULAR CIRCUMSTANCES. THE USER MUST ALSO CONSIDER THEAPPLICABILITY OF ANY GOVERNMENTAL REGULATORY LIMITATIONS ANDESTABLISHED SAFETY AND HEALTH PRACTICES BEFORE IMPLEMENTING THISDOCUMENT.

THE USER OF THIS DOCUMENT SHOULD BE AWARE THAT THIS DOCUMENT MAY BEIMPACTED BY ELECTRONIC SECURITY ISSUES. THE COMMITTEE HAS NOT YETADDRESSED THE POTENTIAL ISSUES IN THIS VERSION.

The following individuals served as members of ISA Subcommittee ISA75.11 and approved thisstandard:

NAME COMPANY

H. Maxwell, Chairman Bechtel Power Corporation

W. Weidman, Managing Director WCW ConsultingH. Boger GE EnergyE. Bunke Badger MeterC. Crawford ConsultantR. Duimstra Fisher Controls International Inc.M. Hellman Leslie Controls Inc.J. Kiesbauer Samson AktiengesellschaftV. Mezzano Fluor CorporationS. Samy CCIE. Skovgaard Control Valve SolutionsR. Terhune ConsultantS. Weiner ConsultantJ. Young The Dow Chemical Company

The following people served as members of ISA Committee ISA75 and approved this standard:

NAME COMPANY

J. Young, Chairman The Dow Chemical CompanyW. Weidman, Managing Director WCW ConsultingL. Al-Awami Saudi AramcoH. Baumann H B Services Partners LLCJ. Beall Emerson Process ManagementM. Bober Copes-VulcanH. Boger GE EnergyG. Borden Consultant

S. Boyle Metso Automation USA Inc.J. Broyles Enbridge Pipelines Inc.F. Cain Flowserve CorporationR. Duimstra Fisher Controls International Inc.J. Faramarzi Control Components Inc.T. George Richards IndustriesC. Hergert Kellogg Brown & RootH. Hoffmann ConsultantJ. Jamison EnCana Corporation Ltd.J. Kiesbauer Samson Aktiengesellschaft


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A. Libke DeZurikG. Liu ConsultantH. Maxwell Bechtel Power CorporationJ. McCaskill Expro GroupA. McCauley Chagrin Valley Controls Inc.R. McEver ConsultantV. Mezzano Fluor CorporationH. Miller ConsultantT. Molloy CMES Inc.L. Ormanoski ConsultantJ. Reed ConsultantE. Skovgaard Control Valve Solutions

This standard was approved for publication by the ISA Standards and Practices Board on14 January 2013.

NAME COMPANY

D. Dunn, Vice President Aramco Services Co.

R. Bartusiak ExxonMobil Chemical CompanyP. Brett Honeywell Inc.J. Campbell ConsultantM. Coppler Det Norske Veritas Certification Inc.E. Cosman The Dow Chemical Co.B. Dumortier Schneider ElectricJ. Federlein Federlein & Assoc. Inc.J. Gilsinn Kenexis ConsultingE. Icayan ACES Inc.J. Jamison Spectra Energy Ltd.K. Lindner Endress+Hauser Process Solutions AGV. Maggioli Feltronics Corp.T. McAvinew Instrumentation and Control Engineering LLCR. Reimer Rockwell Automation

S. Russell Valero Energy Corp.N. Sands DuPontH. Sasajima Azbil Corp.T. Schnaare Rosemount Inc.J. Tatera Tatera & Associates Inc.I. Verhappen Industrial Automation Networks Inc.W. Weidman WCW ConsultingJ. Weiss Applied Control Solutions LLCM. Wilkins Yokogawa IA Global Marketing (USMK)D. Zetterberg Chevron Energy Technology Company


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Contents

1 Scope .............................................................................................................................. 92 Basic definitions ............................................................................................................... 9

2.1

Terminology ............................................................................................................ 9

3 Typical inherent flow characteristics ................................................................................. 94 Permissible deviations between actual and manufacturer-stated inherent flow

characteristics ................................................................................................................ 10


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1 Scope

The scope of this standard is to define the statement of typical control valve inherent flowcharacteristics and inherent rangeabilities, and to establish criteria for adherence tomanufacturer-specified flow characteristics.

2 Basic definitions

2.1 Terminology

Basic terminology used herein is based on definitions stated in "Control Valve Terminology"ANSI/ISA-75.05.01-2000 (R2005) or applicable IEC standar ds.

2.1.1 flow coefficient:a constant (Cv), related to the geometry of a valve, for a given valve opening, that can be used topredict flow rate. See ANSI/ISA-75.01.01 (IEC 60534-2-1 Mod)-2007, "Flow Equations for SizingControl Valves," and ANSI/ISA-75.02.01-2008, "Control Valve Capacity Test Procedures." Kvcanbe substituted for Cv, where 1 Kv= 0.85 Cv.

2.1.2 inherent flow characteristic:

the relationship between the flow rate through a valve and the travel of the closure member asthe closure member is moved from the closed position to rated travel with constant pressure dropacross the valve.

2.1.3 inherent rangeability:the ratio of the largest flow coefficient (Cv) to the smallest flow coefficient (C v) within which thedeviation from the specified inherent flow characteristic does not exceed the limits stated inClause 4.

The stated inherent rangeability of a specific control valve is related solely to the interactionbetween the closure member and the flow control orifice of a valve. Other factors such as thepositioning accuracy of the actuator or the effects of hydraulic flow resistance of associatedpiping should be considered when deriving the installed rangeability for a specific application.

Within the limitation given in 4.1, both the flow coefficient deviation given in Figure 1 and theslope deviations given in Figure 2 are applicable in determining the inherent rangeability. Onlythe slope deviations are applicable for C vvalues below 5.

2.1.4 relative flow coefficient ():the ratio of the flow coefficient (C v) at a stated travel to the flow coefficient (C v) at rated travel.

2.1.5 relative travel (h):the ratio of the travel at a given opening to the rated travel.

3 Typical inherent flow characteristics

3.1 The typical inherent flow characteristic for a specific size, type, and trim configuration of a

control valve shall be specified by the manufacturers either graphically or in tabular form.

3.2When tabulated, specific flow coefficients shall be stated for the following travel positions: at5%, 10%, 20%, and every subsequent 10% of rated travel up to and including 100%.

3.3The manufacturer may publish flow coefficients in addition to those at the above-stated travel

positions.


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3.4 In addition, the manufacturer is encouraged to specify the generic name of a specific flowcharacteristic such as "Linear," "Equal-Percentage," etc., if applicable, following the definitions inANSI/ISA-75.05.01-2000 (R2005) .

3.5The manufacturer shall state the largest flow coefficient that meets the criteria of Clause 4 if

it is less than the rated flow coefficient. (See Figure 2.)

4 Permissible deviations between actual and manufacturer -stated inherent flowcharacteristics

4.1 When subjected to a flow test per ANSI/ISA-75.02.01-2008 (IEC 60534-2-3 Mod), the

individual test Cv values may not deviate by more than 10 {1/ }0.2

percent from those valuesspecified in the flow characteristic published by the manufacturer. Exceptions of this are C vs atgiven travel positions falling below a C v value of 5, or above a C v value of 30d

2. In the above

relationships, d is the nominal valve size in inches, and is the relative flow coefficient based onpublished Cvs. Allowable deviations calculated by the above equation are listed in Table 1.

Table1Permissible deviations between actual and manufacturer-statedinherent flow characteristics

% CvRated Permitted +/-

Deviation (%)

Range

High Low

5 0.05 18.2 0.0591 0.0409

10 0.1 15.8 0.116 0.0842

20 0.2 13.8 0.228 0.172

30 0.3 12.7 0.338 0.262

40 0.4 12.0 0.448 0.352

50 0.5 11.5 0.557 0.443

60 0.6 11.1 0.667 0.533

70 0.7 10.7 0.775 0.625

80 0.8 10.5 0.883 0.717

90 0.9 10.2 0.992 0.808

100 1.0 10.0 1.100 0.900

4.2The inherent flow characteristic of a control valve, when plotted from test data at the statedincrements of travel, shall show no major deviations in slope. By definition, a major deviation iswhen the slope of the line connecting two adjacent test points varies by more than 2 to 1 or 0.5to 1 from the slope of a line drawn between flow coefficients specified by the manufacturer forthe same travel positions. (See Figure 1.)


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INHERENT RANGEABILITY OF TEST

SPECIMEN (per Subclause 2.1.3):

The maximum relative flow coefficientmeeting the requirements of Clause 4 is 1.000; the minimum is 0.021.

Figure1Example of globe valve specimen compared to manufacturer-specified flow characteristic


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INHERENT RANGEABILITY OF TEST =

= 91

SPECIMEN (per Subclause 2.1.3):

The maximum relative flow coefficientmeeting the requirements of Clause 4 is 0.91; the minimum is 0.01.

*Tolerance band for = 0.01 is 10 { }0.2

= 25% of = 0.01.

Figure2Example of butterfly valve specimen compared to manufacturer-specified flow characteristic


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ISBN: 978-0-876640-01-2

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ANSI ISA-75-11-01 (2013)E