1、 MSS SP-91-2009 Guidelines for Manual Operation of Valves Standard Practice Developed and Approved by the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 127 Park Street, NE Vienna, Virginia 22180 Phone: (703) 281-6613 Fax: (703) 281-6671 e-mail: infomss-hq.org www.mss
2、-hq.org MSS STANDARD PRACTICE SP-91iThis MSS Standard Practice was developed under the consensus of the MSS Technical Committee 306 and the MSS Coordinating Committee. The content of this Standard Practice is the result of the efforts of competent and concerned volunteers to provide an effective, cl
3、ear, and non-exclusive specification that will benefit the industry as a whole. This MSS Standard Practice is intended as a basis for common practice by the manufacturer, the user, and the general public. The existence of an MSS Standard Practice does not in itself preclude the manufac- ture, sale,
4、or use of products not conforming to the Standard Practice. Mandatory conformance is established only by reference in a code, specification, sales contract, or public law, as applicable. Unless otherwise specifically noted in this MSS SP, any standard referred to herein is identified by the date of
5、issue that was applicable to the referenced standard(s) at the date of issue of this MSS SP. In this Standard Practice all notes, annexes, tables, and figures are construed to be essential to the understanding of the message of the standard, and are considered part of the text unless noted as “suppl
6、emental“. All appendi-ces appearing in this document are construed as “supplemental“. Supplemental“ information does not include mandatory requirements. U.S. customary units in this Standard Practice are the standard; metric (SI) units are for reference only. Substantive changes in this 2009 edition
7、 are “flagged” by parallel bars as shown on the margins of this paragraph. The specific detail of the change may be determined by comparing the material flagged with that in the previous edition. Any part of this Standard Practice may be quoted. Credit lines should read extracted from MSS SP-91, 200
8、9 with permission of the publisher, the Manufacturers Standardization Society. Reproduction prohibited under copyright convention unless written permission is granted by the Manufacturers Standardization Society of the Valve and Fittings Industry Inc. Originally Approved 1980 Copyright , 1984 by Man
9、ufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. MSS STANDARD PRACTICE SP-91iiFOREWORD The handwheels or handles provided with manually actuated valves are designed so that reasonable effort exerted by the operator(s) is sufficient to actuate. However, op
10、erability of manually controlled valves is dependent on many factors, such as fluid pressure and temperature, location of valve in relation to operators, desired speed of operation, physical capabilities of operators, ambient conditions, and frequency of operation. The purchaser, based upon anticipa
11、ted on-site conditions, should therefore evaluate suitability of valves with manual actuators. This document was prepared to assist users in establishing actual requirements relative to valve operation. Most valves can be provided with actuators suitable for specific service conditions, regardless o
12、f severity, when conditions are defined. MSS STANDARD PRACTICE SP-91iiiTABLE OF CONTENTS SECTION PAGE 0 PURPOSE 1 1 SCOPE . 1 2 DEFINITIONS 1 3 OPERATORS ABILITY TO APPLY FORCE 2 4 MULTIPLYING FACTORS . 2 5 ADDITIONAL CONSIDERATIONS . 2 6 VALVE OPERATING CHARACTERISTIC CURVES 5 TABLE 1 Input Factor
13、Multipliers . 4 FIGURE 1 Lever Type Manual Actuator 3 2 Handwheel Type Manual Actuator 3 3 T-Lever Type Manual Actuator . 4 4 Globe-Sliding Stem, Flow under Disc . 6 5 Globe-Sliding Stem, Flow over Disc . 6 6 Globe-Threaded Stem, Flow under Disc . 6 7 Globe-Threaded Stem, Flow over Disc . 6 8 Diaphr
14、agm & Pinch Valves . 7 9 Butterfly Valves . 7 10 Ball & Plug Valves 7 11 Gate Valves, Rising or Non-Rising Stem 7 MSS STANDARD PRACTICE SP-9110. PURPOSE The purpose of this Standard Practice is to provide valve users with information for use in evaluating the manual operation of valves. It must be u
15、nderstood that this information is general in nature and must be supplemented by specific operational data for the valve and service conditions to be experienced. The maximum and minimum torque ratings of specific valve and actuator types are not covered by this Standard Practice, but must be consid
16、ered when applying manual input devices to any specific valve. Data from the valve and actuator manufacturers should be consulted regarding valve and actuator types and ratings. 1. SCOPE This Standard Practice provides guidelines for the operation of manually actuated valves as affected by the valve
17、 operators input. 2. DEFINITIONS 2.1 Manual Actuator A device requiring manual force to provide the torque and/or thrust required to operate a valve, including levers, T-levers, T-chain- levers, handwheels, chainwheels, worm gear/spur gear/traveling nut units, and manual override units on power actu
18、ators. 2.2 Manual-Impact Device A hammerblow handwheel or chainwheel device that momentarily increases the breakloose seating and unseating torque capability of handwheels or chainwheels by the application of impact forces. 2.3 Power Actuator A mechanism for actuating valves using other than manual
19、input to apply force or energy, such as pneumatic, electric, and hydraulic units. 2.4 Operator Person or persons who apply manual force to an actuating device. A typical operator is one who is capable of exerting approxiamately 150 pounds of force (670 N) on a lever with an effective length of 12 in
20、ches (300 mm) at waist level. If the intended operators or the system requirements differ, specific information should be obtained from the valve supplier. 2.5 Effective Lever or Effective T-Lever Length The actual lever length measured from the stem-center to the center of force application, 1 1/2
21、inches (38 mm) from the lever end, or the total T-lever length less 3 inches (76 mm). 2.6 Effective T-Chain-Lever Length The length from stem center to the center of the chain attachment multiplied by the sine of the angle included between lever and chain in the position under consideration. 2.7 Ava
22、ilable Lever Torque The product of a force exerted on a lever at the effective lever-length, multiplied by the effective lever-length. 2.8 Handwheel Rim-Force The total rim-force exerted on the rim of a handwheel or on the spokes of a capstan handwheel, which is the sum of a push- and-pull force. 2.
23、9 Available Handwheel Torque A product of the handwheel rim force multiplied by the handwheel radius (handwheel diameter divided by 2), or if a capstan handwheel, spoke forces multiplied by the length of one spoke, measured from the center of the handwheel less 1 1/2 inches (38 mm). 2.10 T-Chain-Lev
24、er or Chainwheel Torque The product of the total pull force exerted by the operator multiplied by the chainwheel radius (effective chainwheel diameter divided by 2) or multiplied by the effective T-chain lever length. 2.11 Normal Operating Conditions This refers to the conditions experienced by one
25、operator when attempting to apply force to an actuating device. Normal conditions are with the manual actuator at waist level and the plane of rotation of the lever, handwheel, or chainwheel located vertically or horizontally, with temperature at 700F (200C), good footing, and with no space restrict
26、ions. 2.12 Momentary Force If an operator must apply a high force to a manual actuator to cause a valve to break loose, but may exert relatively lower forces to continue actuation of the valve, the initial high force is referred to as a momentary force. Guidelines for Manual Operation of Valves MSS
27、STANDARD PRACTICE SP-9122.13 Short-Term Force The force an operator could be expected to exert on an actuating device for a small portion of the total valve travel such as for seating and unseating. 2.14 Uniform Force The force that an operator could be expected to exert for a period of up to 5 minu
28、tes. May be used on certain valves that require an operator to exert a relatively constant force on an actuating device throughout the valve travel. 2.15 Long-Term Force The force an operator could be expected to exert on an actuating device for extended periods of time. 2.16 Valve Operating Charact
29、eristics Forces developed on the valve stem, hence the actuator, during the closed-open-closed operating cycle are indicated in terms of: 2.16.1 Torque A turning moment developed on stems of valves such as quarter-turn ball, plug, and butterfly or on the stem nuts of globe or gate valves. 2.16.2 Thr
30、ust Axial force developed on valve stems, such as globe or gate valves. 2.17 Net Mechanical Advantage A multiplying factor for gearing that includes both the gear ratio and the efficiency of the device. 3. OPERATORS ABILITY TO APPLY FORCE 3.1 Discussion The selection of manual actuators on valves sh
31、ould take into consideration the ability of operators to apply adequate force to the device. This ability is dependent upon several factors, such as: a) Space available and position of the device to which force is applied. b) Operators physical strength, weight, and height. c) Nature of force requir
32、ed such as momentary, short-term, uniform long-term, or sudden unexpected. d) Environmental conditions, such as temperature, humidity, footing, bracing, and protective clothing. e) Frequency of operation and urgency of operation. 3.2 Figures Figures 1, 2, and 3, represent operator capabilities as re
33、lated to manual actuator dimensions and are not intended to cover all possible valve service and differential pressure conditions. Information presented in these figures must be tempered to account for operating conditions in Section 3.1. 3.3 Chainwheels No figure is included for chainwheel size vs.
34、 force input capability, as the input to a chainwheel depends upon operator weight and is not related to chainwheel size alone. 4. MULTIPLYING FACTORS 4.1 Input Factors As indicated in Section 3.1, certain factors affect the ability of an operator to apply force to an actuating device. A list of the
35、se factors is provided in Table 1 along with a multiplier that may be used in conjunction with Figures 1, 2, and 3. To use, refer to the applicable Figure as determined by the actuating device, locate the operator force input capability and multiply this input capability by the factor given in Table
36、 1 for the position factor. Multiply that result by the smallest factor found for all other input considerations. 4.2 Mechanical Advantage Depending on the torque or thrust necessary to operate the valve, the operator input force may be amplified, typically through the use of gearing. In these cases
37、, the force capability is multiplied by the appropriate net mechanical advantage of the gearing. 5. ADDITIONAL CONSIDERATIONS In addition to the multiplying factors provided in Table 1, other factors contribute to the limitations of manual valve operation. These include: 5.1 Speed of Operation Manua
38、l operation may actuate a valve too slowly in an emergency situation. Rapid manual valve operation such as is possible with a lever actuator, may cause system damage through “water hammer”. MSS STANDARD PRACTICE SP-913Figure 1 Lever Type Manual Actuator (effective lever length vs. force input capabi
39、lity with normal operating conditions) Figure 2 Handwheel Type Manual Actuator (handwheel diameter vs. force input capability with normal operating conditions) MSS STANDARD PRACTICE SP-914Figure 3 T-Lever Type Manual Actuator (T-lever lengths vs. force input capability with normal operating conditio
40、ns) Note: Data displayed in Figures 1 thru 3 is based upon combined test data furnished by several valve manufacturers for typical operating input force capabilities. Table 1 Input Factor Multipliers Input Factor Multiplier Position Shoulder level to hip level 1 Below hip level 0.5 Above shoulder le
41、vel 0.5 Manual Impact Devices(1)12” diameter (300 mm) 2 24” diameter (600 mm) 3 36” diameter (900 mm) 4 Space Available Must be considered on an individual basis Momentary Force 1.0 Short-Term Force 0.85 Uniform Force 0.7 Long-Term Force 0.25 Environmental Considerations Must be considered on an ind
42、ividual basis Note: (1)The effectiveness of impact devices is dependent on the diameter and length of the stem shaft and the mass of the handwheel. Consult the valve manufacturer for recommendations for using impact devices. MSS STANDARD PRACTICE SP-9155.2 Sudden, Unexpected Forces Sudden, unexpecte
43、d forces can be encountered on quarter-turn valves which may develop high dynamic forces at certain angles of opening at high-flow velocity. The ability of an operator to apply force to a manual actuating device is dependent upon the operators ability to react to the force requirement. Given a set o
44、f operating conditions, a maximum capability to apply force exists for each operator. However, if the force is unexpected and sudden, such as to allow little time for reaction, the operators ability to respond is hampered. 6. VALVE OPERATING CHARACTERISTIC CURVES Figures 4 through 11 indicate typica
45、l operating characteristics for commonly used styles of general-purpose valves. The curves indicate the torque or thrust needed to move the closure member from closed-to-open-to-closed position. Positive values of torque or thrust indicate that the closure member resists the operating of closing eff
46、ort. Negative values indicate that the closure member aids that effort. The actual curve for a specific valve is dependent upon a number of factors and can vary according to valve geometry and operating conditions. Hence, only a broad-band curve is shown for each valve style. Factors affecting speci
47、fic valve characteristic curves include: a) Direction of flow, particularly in valve styles which may be sensitive to flow direction, such as globe or offset-disc butterfly. b) Pressure drop, flow medium and/or flow rate, which affect the amplitude of the curves. c) Valve size, since curve shape and
48、 amplitude for a valve style may change as the size factors of various valve components change. d) Frequency of operation may affect seating and unseating forces, particularly if valves are operated infrequently. e) Unique design features of any particular valve style or manufacturer may change the
49、shape and/or amplitude of the characteristic curves. MSS STANDARD PRACTICE SP-916Figure 4 Globe-Sliding Stem, Flow under Disc(1) Figure 6 Globe-Threaded Stem, Flow under Disc(1) Note: (1) Single seated globe valves Figure 5 Globe-Sliding Stem, Flow over Disc(1) Figure 7 Globe-Threaded Stem, Flow over Disc(1)MSS STANDARD PRACTICE SP-917Figure 8 Diaphragm & Pinch Valves Figure 10 Ball & Plug Valves Figure 9 Butterfly Valves Figure 11 Gate Valves, Rising or Non-Rising Stem(1) Note: (1)Negative values are not applicable to torque characteristics for threaded stem valves. List of MSS
