1、 ANSI/FCI 91-1-2010 AMERICAN NATIONAL STANDARD STANDARD FOR QUALIFICATION OF CONTROL VALVE STEM SEALS Fluid Controls Institute, Inc. Sponsor: Fluid Controls Institute, Inc. 1300 Sumner Ave Cleveland, Ohio 44115-2851 ANSI/FCI 91-1-2010 AMERICAN NATIONAL STANDARD Standard for Qualification of Control
2、Valve Stem Seals Sponsor Fluid Controls Institute, Inc. iiAmericanNationalStandardAmerican National Standard implies a consensus of those substantially concerned with its scope and provisions. An American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general
3、 public. The existence of an American National Standard does not in any respect preclude anyone, whether he has approved the standard or not, from manufacturing, marketing, purchasing or using products, processes, or procedures not conforming to the standard. American National Standards are subject
4、to periodic review and users are cautioned to obtain the latest editions. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken to reaffirm, revise, or withdraw this standard n
5、o later than five years from the date of publication. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Sponsored and published by: FLUID CONTROLS INSTITUTE, INC. 1300 Sumner Avenue Cleveland, O
6、H 44115-2851 Phn: 216/241-7333 Fax: 216/241-0105 E-Mail: fcifluidcontrolsinstitute.org URL: www.fluidcontrolsinstitute.org Copyright 2010 by Fluid Controls Institute, Inc. All Rights Reserved No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, w
7、ithout the prior written permission of the publisher. Suggestions for improvement of this standard will be welcome. They should be sent to the Fluid Controls Institute, Inc. Printed in the United States of America iiiCONTENTS PAGE Foreword - v 1. Purpose - 1 2. Definitions - 1 3. Scope and Limitatio
8、ns - 1 4. Classifications - 1, 3 5. Test Requirements - 2-3 6. Testing - 3-4 7. Test Report Requirements- 4 Table Table 1 - Steam Seal Class Summary - 2 Figures Figure 1 Qualified Pressure and Temperature Rating Example - 5 Figure 2 Expanded Qualified Pressure and Temperature Rating Example - 6 Figu
9、re 3 Class A Example Test Profile - 7 Figure 4 Class B Example Test Profile - 8 Figure 5 Class C Example Test Profile - 9 Figure 6 Class D Example Test Profile - 9 Figure 7 Class E Example Test Profile - 10 ivForeword (This foreword is included for information only and is not part of ANSI/FCI 91-1,
10、Standard for Qualification of Control Valve Stem Seals). This voluntary standard has been developed through the cooperative efforts of the members of the Control Valve Section of the Fluid Controls Institute, Inc. (FCI). Its purpose is to assist users and specifiers of control valves in their effort
11、s to comply with federal and state equipment leak regulations as they relate to leak detection and repair. The purpose of this standard is to provide a means of evaluating the sealing properties of a stem seal design under a standard set of test conditions in a laboratory environment. Compliance wit
12、h this standard does not provide proof of actual performance in a process plant due to the variance in actual process service conditions. Compliance by the manufacturer with this standard does not waive any federal or state leak detection and repair requirements on the part of the end user. Stem sea
13、ls meeting this standard are believed to enhance the end users capability in meeting the equipment leak requirements. This standard was originally adopted as an FCI standard January 29, 1991. The standard has been periodically revised and the latest revision was approved in August, 2010. The existen
14、ce of an FCI standard does not in any respect preclude any member or non-member from manufacturing or selling products not conforming to the standard. It should be clearly understood that this is a voluntary standard and the FCI is not responsible for its use. FCI recognizes the need to periodically
15、 review and update this standard. Suggestions for improvement should be forwarded to the Fluid Controls Institute, Inc., 1300 Sumner Avenue, Cleveland, Ohio, 44115-2851. All constructive suggestions for expansion and revision of this standard are welcome. vANSI/FCI 91-1-2010 AMERICAN NATIONAL STANDA
16、RD Standard for Qualification of Control Valve Stem Seals 1. PURPOSE This standard classifies control valve stem seals by their ability to withstand mechanical and thermal cycles at a specified set of temperature and pressure conditions. Bellows, diaphragms, and tubular seals are not covered by this
17、 standard. 2. DEFINITIONS 2.1 Control Valve - A valve with a power positioning actuator for moving a closure member to any position relative to a valve port or ports in response to an external signal. The power for a control valve actuator is derived from an independent source. 2.2 Fugitive Emission
18、s - Those emitted from process equipment. Any unwanted leak to atmosphere. 2.3 Mechanical Cycle - Moving the valve stem or shaft from the fully closed position to the fully open position and back to the fully closed position. 2.4 Proof of Design - A test to qualify stem seal design to meet the requi
19、rements for a class shown in Table 1. 2.5 Rated Travel - The valve travel at which the manufacturers rating is established. 2.6 Stem Seal - The means of preventing leakage of process fluid to the atmosphere where the stem protrudes from the valve body assembly. The stem seal also includes any loadin
20、g or retaining mechanism. 2.7 Stem Seal Leakage - The concentration of process fluid being emitted past the stem seal under the defined test conditions. For this standard methane will be used exclusively as the process fluid, except at elevated temperatures. 2.8 Stem Seal Cross Section - 1/2 (Bore D
21、iameter - Stem Diameter). This definition is consistent with commonly used terminology in the packing industry and is equivalent to gland width, packing cross section, or packing size. 2.9 Stem Seal Adjustment - The use of a wrench or other tool to move any mechanism which retains or applies stress
22、to the stem seal components. 3. SCOPE AND LIMITATIONS 3.1 This standard shall apply to rotary and linear motion control valves. Bellows, diaphragms and tubular stem seals are not covered by this standard. 3.2 This standard shall not apply to valves that are governed by conflicting national or intern
23、ational standards. 3.3 Municipal, state and federal regulations may require additional qualifications testing that is beyond the scope of this standard. 3.4 The test results from this standard shall only be used to predict leakage at conditions within the qualified pressure and temperature rating. 3
24、.5 The laboratory proof of the design as described may not guarantee similar results when the control valve is exposed to different field process conditions. 4. CLASSIFICATIONS 4.1 To qualify to this test standard the valve stem seal shall be tested to one of the classes shown in Table 1 to either a
25、 100 ppm or 500 ppm maximum stem seal leakage criteria as specified. 12TABLE 1 Stem Seal Class Summary Class Number of Mechanical Cycles Number of Thermal Cycles Maximum Stem Seal Leakage EPA Method 21 Adjustments Allowed Monitoring Frequency A1 100,000 3 100 None See Figure 3 A2 100,000 3 500 None
26、See Figure 3 B1 25,000 3 100 None See Figure 4 B2 25,000 3 500 None See Figure 4 C1 100,000 None 100 None See Figure 5 C2 100,000 None 500 None See Figure 5 D1 25,000 None 100 None See Figure 6 D2 25,000 None 500 None See Figure 6 E1 5,000 1 100 1 See Figure 7 E2 5,000 1 500 1 See Figure 7 4.2 It is
27、 permissible to choose a Class B test profile, and at the successful completion of the test continue mechanical cycle testing to the Class A test profile with the same stem seal. Referring to Figure 3, continuation of the test would start at the 25,000 cycle point of the Class A test profile resulti
28、ng in two additional thermal cycles. Stem seal adjustment is not permitted during or between the tests. 4.3 It is permissible to choose a Class D test, and at the successful completion of the test continue mechanical cycles with the same stem seal until a Class C test is completed. Stem seal adjustm
29、ent is not permitted during or between the tests. 5. TEST REQUIREMENTS 5.1 The maximum allowable fugitive emission leakage of the stem seal from the test valve or fixture to qualify to this test standard is 100 or 500 ppm (refer to Table 1) concentration using 40 CFR Part 60 Method 21 leak detection
30、 method with the test valve or fixture pressurized with methane (at least 98% pure). The instrument used to measure the methane concentration must meet the specifications and performance criteria set forth in EPA Method 21. Provisions shall be taken to negate the favorable effects of wind on OVA mea
31、surements when the average wind speed is above 10 mph. 5.2 To ensure stem seal test validity, a background reading shall be measured and recorded prior to measuring the stem seal leakage. If the background is above 10 ppm all gasket joints shall be leak tested per Method 21. 5.3 The test valve stem
32、seal shall not be disturbed, adjusted, or receive any maintenance throughout the qualification test. The only exception to this rule is Class E in which one adjustment is allowed. 5.4 The valve stem seal shall be tested in the valve style for which it is to be qualified. For example, a valve stem se
33、al which was tested and qualified in a sliding stem valve is not qualified for rotary valves, unless it was also tested and qualified in a rotary valve. 5.5 Varying the basic height or configuration of a stem seal, such as the type, arrangement, or number of components, shall require the altered ste
34、m seal to be qualified separately. Varying the height of non-sealing and rigid components, such as spacers or lantern rings, is permitted. 5.6 The qualification test for a stem seal applies only to valves with rated travel equal to, or less than, the travel used in the valve or fixture tested, excep
35、t that a stem seal which has been qualified to Class A is also qualified to Class B, with an increase in rated travel equal to four times the travel used in the Class A qualification test. Similarly, a stem seal which has been qualified to Class C is also qualified to Class D, with an increase in ra
36、ted travel equal to four times the travel used in the Class C qualification test. 5.7 The stem sizes qualified for a valve stem seal by successful completion of a test, or series of tests, are from 0.5 to 2.0 times the tested stem diameter. 5.8 The cross sections qualified for a valve stem seal by s
37、uccessful completion of a test, or series of tests, are from 0.8 to 1.2 times the tested cross section. 5.9 The valve stem seal shall be tested in such a way as to remove any benefit from a backseat to insure that the stem seal is fully pressurized. 35.10 A test fixture may be used instead of a test
38、 valve when size or other factors make it more practical. The test fixture must have the same dimensions as the valve it is simulating for all design features which will affect the stem seal. 5.11 For rotary valves, as well as for valves having linear stem motion, the closure element shall be fully
39、engaged with the seat on every mechanical cycle of the test valve, and pressure loads on the shaft that are not present during the test shall be simulated, thereby reproducing the normal and expected bending loads in the stem or shaft that the valve would encounter in service. If a test fixture is u
40、sed it must simulate these bending loads. 5.12 The temperature and pressure conditions of the qualification test are defined by T1 and corresponding P1 and a different T2 and corresponding P2. These temperatures and pressures are chosen before starting the qualification test and controlled throughou
41、t the test. T1 must always be equal to or greater than -40F and less than or equal to 100F. If T2 is greater than 100F, then P2 may be equal to, but not greater than P1. The temperature and pressure conditions chosen for the qualification test determine the rating for the stem seal as illustrated by
42、 the crosshatched region in Figure 1. 5.13 A thermal cycle of the stem seal is accomplished by starting at T1, P1 and changing to T2, P2 and then returning to T1, P1 while adhering to the prescribed number of mechanical cycles. A complete test profile for each class is illustrated in Figures 3, 4, 5
43、, 6 & 7. A thermal cycle must also be greater than 110F (T2-T1 must be greater than 110F). 5.14 The rating for a stem seal may be expanded by performing additional tests with new stem seal components. On subsequent tests, T1 and P1 must be equal to the previously chosen T1 and P1. The requirement fo
44、r the thermal cycle to be at least 110F no longer applies because this requirement was met during the first test. A range curve that has been expanded with an additional test is shown in Figure 2. 5.15 Temperature measurement shall be made by attaching a thermocouple or other contact type measuremen
45、t system to the test valve or fixture adjacent to the center of the stem seal. If the body wall thickness of the test valve or fixture adjacent to the stem seal is greater than 1/2 inch, then a small diameter hole shall be drilled into the test valve or fixture for the thermocouple to be inserted, s
46、uch that the thermocouple is no more than 1/2 inch from the stem seal. 5.16 The test medium shall be nitrogen, air, or methane. If the test medium is air which is supplied by a compressor, precaution must be taken to insure that the air is free of oil from the compressor. The use of methane as a test medium at elevated temperatures is not recommended for safety reasons. 6. TESTING Conducting the test in accordance with the test procedu
