1、 MSS SP-45-2003 Reaffirmed 2008Bypass and Drain Connections 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.m
2、ss-hq.org MSS STANDARD PRACTICE SP-45iThis MSS Standard Practice was developed under the consensus of the MSS Technical Committee 106 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,
3、clear, 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 manufacture, 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. U.S. customary units in this Standard Practice are the standard; the metric units are for reference only. In this
5、 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 “supplemental“. All appendices appearing in this document are construed as “supplemental“. Supplemental“ i
6、nformation does not include mandatory requirements. Non-toleranced dimensions in this Standard Practice are nominal, and, unless otherwise specified, shall be considered “for reference only”. Any part of this standard may be quoted. Credit lines should read extracted from MSS SP-45, 2003 Reaffirmed
7、2008 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 July, 1953 Copyright , 19
8、82 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. MSS STANDARD PRACTICE SP-45iiFOREWORD The 1953 edition of MSS SP-45-1953 Bypass and Drain Connections Standard Practice was a combination of two former MSS Standard Practices; MSS SP-5-1944 By-Pass
9、 Size Standard Practice and MSS SP-28-1943 Drain Tapping Standard Practice. As the subject matter of these two Standard Practices is so closely related they were combined as a convenience to the user. MSS SP-5 was originally adopted in 1924 and applied to steel gate valves only. Bosses on steel cast
10、ings of that period presented a more complex problem than castings of other metals and the diversification of requests in regard to size, location, and number of bosses on the part of users prompted the MSS to initiate a standardization program on the subject. The original Standard Practice establis
11、hed the number of bosses, minimum O.D. of boss, and the pipe thread size for steel gate valves in sizes 3 to 24 inch inclusive. The bosses were intended to be used for both bypass and drain connections. In 1937 a new edition of SP-5 was adopted. This edition was greatly expanded over the original an
12、d included both cast iron and steel valves in the gate, globe and angle patterns. The subject matter was confined to by-passes only and standard locations were established for the bypass on each type of valve. Two sets of bypass sizes were established; one for the purpose of warming up main lines be
13、fore opening the main valve and one for the purpose of balancing the pressure on both sides of the main valve to facilitate its operation. The edition has been reaffirmed periodically up to the promulgation of the new MSS SP-45. MSS SP-28 was originally adopted in 1937 and was also prompted by the v
14、ariety of user requests for connections on valves and fittings at odd locations and varying sizes, with and without bosses. SP-28 established standard drain sizes for each size valve and fitting, standard maximum sizes for unbossed tappings and standard locations with standard symbols to designate t
15、he location. MSS SP-28 was revised in 1945 at which time a standard method of designating openings of reducing fittings was added. This Standard Practice was also periodically reaffirmed. The 1953 edition of MSS SP-45 combined these two Standard Practices so that the user has all information pertain
16、ing to bypass and drain connections in a single document. In this edition the newer methods of making attachments, such as butt-weld have been recognized. The 1971 edition expanded the coverage of the document by including coverage of ball valves. In preparing this edition, the entire Standard Pract
17、ice was reviewed and up-dated to keep pace with the expanding technology. The 1976 edition expanded the coverage of the bypass sizes to include valves through NPS 48 and the document has been metricized. The 1982 edition expanded the coverage of the document to include plug valves. The 1987 edition
18、was a reaffirmation of the 1982 edition with no substantive change. The 1992 edition changed the title, removed metric units, and made several editorial changes. The 1998 edition added metric units and made several editorial and format changes. The 2003 edition was issued with only editorial changes
19、. The 2008 edition was a reaffirmation of the 2003 edition with one editorial change in Annex A. MSS STANDARD PRACTICE SP-45iiiTABLE OF CONTENTS SECTION PAGE 1 SCOPE. 1 2 LOCATION AND SYMBOLS . 1 3 STANDARD DRAIN SIZES 1 4 STANDARD BYPASS SIZES1 5 BYPASS LOCATIONS 2 6 DRAIN AND BYPASS CONNECTION DIM
20、ENSIONS 3 7 BOSSES 3 8 REDUCTION FITTINGS . 3 TABLE 1 Standard Drain Sizes . 1 2 Bypass Sizes 2 3 Connection Dimensions. 4 FIGURE 1 Minimum Thread Length. 3 2 Welding Socket Dimensions . 3 3 Butt-Weld 4 4 Bosses 4 5 Method of Designating Location of Opening for Drains & Bypasses. 5 6 Method of Desig
21、nating Location of Opening for Drains. 6 ANNEX A Referenced Standards and Applicable Dates. 7 MSS STANDARD PRACTICE SP-4511. SCOPE 1.1 This Standard Practice establishes requirements for connections to valves and fittings to accommodate drains and bypasses in all pressure classes. 1.2 Specific requi
22、rements are: a) Standard symbols and locations of openings for drains and bypasses. b) Standard size of drains and bypass openings. c) Minimum thread lengths in drain and bypass tappings. d) Minimum diameter and depth of socketweld connection for drain and bypass. e) Butt-welding connection for drai
23、n and bypass. f) Bosses for drain and bypass connection. g) Method for designating outlets of reducing fittings. 2. LOCATION AND SYMBOLS 2.1 Figures 5 and 6 illustrate the application of standard symbols for the locations of openings for drain and bypass connections recognized as standard. These sym
24、bols should be regularly employed on drawings, specifications requisitions, and other instruments used in the transactions of business. 2.2 When a tap is required at some other location, it is recommended that the manufacturer by consulted as to their practicability, and both the inquiry and the ord
25、er should be accompanied by a sketch indicating the location upon the fitting of valve body. 3. STANDARD DRAIN SIZES 3.1 When fittings and valves require drain openings, they are regularly furnished with the size shown in Table 1 unless otherwise specified by purchaser. TABLE 1 Standard Drain Sizes
26、Valve or Fitting Size Drain Size NPS DN NPS DN 2-4 50-100 1/2 15 5-8 125-200 3/4 20 10-24 250-600 1 25 4. STANDARD BYPASS SIZES 4.1 When valves are ordered with bypass attached, the size of bypass shall be as shown in Table 2, except where unusual service conditions warrant consideration of a specia
27、l oversize bypass, then the installation of the bypass around the main valve is recommended wherever possible. BYPASS AND DRAIN CONNECTIONSMSS STANDARD PRACTICE SP-452TABLE 2 Bypass Sizes Bypass NPS (DN) Main Valve NPS (DN) Series A (a)Series B (b)2 to 4 (50 to 100) 5 (125) 6 (150) 8 (250) 10 (250)
28、1/2 3/4 3/4 3/4 1 (15) (20) (20) (20) (25) 1 1 1/4 1 1/4 1 1/2 1 1/2 (25) (32) (32) (32) (32) 12 (300) 14 (350) 16 (400) 18 (450) 20 (500) 1 1 1 1 1 (25) (25) (25) (25) (25) 2 2 3 3 3 (50) (50) (80) (80) (80) 24 (600) 30 (750) 36 (900) 42 (1100) 48 (1200) 1 1 1 1 1 (25) (25) (25) (25) (25) 4 4 6 6 8
29、 (100) (100) (150) (150) (200) Notes: (a) Series A is for preheating the piping system (normally with steam) before opening main valve and for balancing pressures where lines are of limited volume. (b) Series B is for lines conveying gases or liquids where bypassing may facilitate the operation of t
30、he main valve by balancing the pressure on both sides of the disc or discs. These larger sizes may be of the bolted on type. 5. BYPASS LOCATIONS 5.1 Gate Valves When gate valves are ordered with bypass attached, is shall be standard practice to attach the bypass at the side of the main valve with th
31、e stems of both valves pointing upward. The more common of the “Special” attached locations is on the center of the flow line, at the bottom of the main valve, (see Figure 5 locations C & D) with the stem of the bypass valve at right angles to the main valve stem. This is designated as the “bottom a
32、ttachment”, or defined as “bypass at the bottom”. When any other “special attached location” or other position of the bypass valve is desired, a sketch should be sent to the manufacturer. 5.2 Globe Valves When globe valves are ordered with bypass attached, it shall be regular to attach bypass at the
33、 right-hand side of the main valve, (see Figure 4 locations E & F) with the stems of the both valves parallel, pointing vertically upward. When bypass may be “specially” required attached at the left-hand side, (see Figure 5 locations A & B) the designation shall be “left-hand attachment”. Right-han
34、d side of a globe valve is the side at the right, when facing the flow port which leads to the underside of the disc. 5.3 Angle Valves When angle valves are ordered with bypass attached, it shall be standard practice to attach bypass at the back of the main valve, (see Figure 5 locations E & F) with
35、 the stems of both parallel, pointing vertically upward. When bypass may be “specially” required attached at the right-hand or left-hand side, (see Figure 5 locations C & D and A & B respectively) the designation shall be “right-hand attachment” or “left-hand attachment”. Right-hand side of an angle
36、 valve is at the right, when facing the back of the valve. 5.4 Check Valves When check valves are ordered with bypass attached, it is standard practice to attach the bypass at the side of the check valve so that the bypass valve stem and the check valve cap both point upward. If location of bypass i
37、s important its location should be specified according to Figure 5. 5.5 Ball Valves When ball valves are ordered with bypass attached, it shall be standard practice to attach the bypass at the side of the main valve with the stems of both valves pointing upward. If location of bypass is important it
38、s location should be specified according to Figure 5. MSS STANDARD PRACTICE SP-4535.6 Plug Valves When plug valves are ordered with bypass attached, it shall be standard practice to attach the bypass at the side of the main valve with the stems of both valves pointing upward. If the main valve shoul
39、d have a handwheel on the side of the valve, the bypass, where possible, should be located on the handwheel side. If any other location is required, position should be specified according to Figure 5. 6. DRAIN & BYPASS CONNECTION DIMENSIONS 6.1 Pipe Threads Pipe threads shall be tapered pipe threads
40、 in accordance with ASME B1.20.1. Metal thickness shall be sufficient to allow the effective thread length specified in Table 3. These lengths are equal to the effective thread lengths of tapered external pipe threads, ASME B1.20.1. Where wall thickness is insufficient or the tapped hole needs reinf
41、orcement, a boss is required. 6.2 Sockets Sockets (socket-welding) may be provided in the wall of a fitting or valve if the metal thickness is sufficient to allow the depth of socket specified in Table 3. Where the wall thickness is insufficient, or the size of socket requires opening reinforcement,
42、 a boss is required. FIGURE 1 Minimum Thread Length 6.3 Butt Welds Connections may be made by butt-welding directly to the wall of the fitting or valve, see Table 3. 7. BOSSES 7.1 When a boss is required to meet the thicknesses in Table 3, the diameter shall be not less than those shown in Figure 4.
43、 8. REDUCING FITTINGS 8.1 When a drain opening is required on the side of a reducing fitting whose side is tapered, the axis of the drain opening should be at right angles to the centerline of the fitting. 8.2 The size of the drain opening on a reducing fitting shall be governed by the size of the a
44、djacent outlet. 8.3 When a tap is required on a reducing fitting at a point centrally located, such “G” on a reducer, its size shall be governed by the average of the drain openings which would be used for the largest and smallest outlet, using the drain opening size which is standard, or the next s
45、maller size as shown in Table 1. FIGURE 2 Welding Socket Dimensions MSS STANDARD PRACTICE SP-454FIGURE 3 Butt Weld Connection Size Boss Diameter “J” NPS DN inches mm 3/8 10 1.25 32 1/2 15 1.50 38 3/4 20 1.75 44 1 25 2.13 54 1 1/4 32 2.50 64 1 1/2 40 2.75 70 2 50 3.38 86 FIGURE 4 Bosses TABLE 3 Conne
46、ction Dimensions Welding Socket, Figure 2 Connection Size Thread Length L Minimum Figure 1 Diameter A, min. Depth B, min. NPS DN inches mm inches mm inches mm 3/8 10 0.41 11 0.690 17.5 0.19 5 1/2 15 0.53 14 0.855 22 0.19 5 3/4 20 0.55 14 1.065 27 0.25 6.5 1 25 0.68 18 1.330 34 0.25 6.5 1 1/4 32 0.71
47、 18 1.675 43 0.25 6.5 1 1/2 40 0.72 19 1.915 49 0.25 6.5 2 50 0.76 20 2.406 61 0.31 8 MSS STANDARD PRACTICE SP-455FIGURE 5 Method of Designating Location of Openings for Drains and Bypasses MSS STANDARD PRACTICE SP-456FIGURE 6 Method of Designating Location of Openings for Drains MSS STANDARD PRACTI
48、CE SP-457ANNEX A Referenced Standards and Applicable Dates This Annex is an integral part of this Standard Practice and is placed after the main text for convenience. Standard Name or Description ASME, ANSI/ASME, ANSI, ASME/ANSI B1.20.1 1983 (R2006) Pipe Threads, General Purpose (Inch) Publications
49、of the following organization appear in the above list: ASME ASME International Three Park Avenue New York, New York 10016-5990 List of MSS Standard Practices (Price List Available Upon Request) Number SP-6-2007 Standard Finishes for Contact Faces of Pipe Flanges and Connecting-End Flanges of Valves and Fittings SP-9-2008 (R 05) Spot Facing for Bronze, Iron and Steel Flanges SP-25-2008 Standard Marking System for Valves, Fittings, Flanges and Unions SP-42-2004 Class 150 Corrosion Resistant Gate, Glove, Angle and Check Valves with Flanged and Butt Weld Ends SP-43-2008 Wrought Stai
