1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 331 Strainers for Flammable Fluids and Anhydrous AmmoniaUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERIAL NOT
2、AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Strainers for Flammable Fluids and Anhydrous Ammonia, UL 331 Eighth Edition, Dated February 25, 2008 Summary of Topics This revision of ANSI/UL 331 is being issued include new 1.4 and new Supple
3、ment SA for Non-Potable Water Strainers. Text that has been changed in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. Changes in requirements are marked with a vertical line in the margin and are followed by an effective date note indicating
4、the date of publication or the date on which the changed requirement becomes effective. The new requirements are substantially in accordance with Proposal(s) on this subject dated March 15, 2013. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or tra
5、nsmitted in any form by any means, electronic, mechanical photocopying, recording, or otherwise without prior permission of UL. UL provides this Standard as is without warranty of any kind, either expressed or implied, including but not limited to, the implied warranties of merchantability or tness
6、for any purpose. In no event will UL be liable for any special, incidental, consequential, indirect or similar damages, including loss of prots, lost savings, loss of data, or any other damages arising out of the use of or the inability to use this Standard, even if UL or an authorized UL representa
7、tive has been advised of the possibility of such damage. In no event shall ULs liability for any damage ever exceed the price paid for this Standard, regardless of the form of the claim. Users of the electronic versions of ULs Standards for Safety agree to defend, indemnify, and hold UL harmless fro
8、m and against any loss, expense, liability, damage, claim, or judgment (including reasonable attorneys fees) resulting from any error or deviation introduced while purchaser is storing an electronic Standard on the purchasers computer system. The requirements in this Standard are now in effect, exce
9、pt for those paragraphs, sections, tables, gures, and/or other elements of the Standard having future effective dates as indicated in the note following the affected item. The prior text for requirements that have been revised and that have a future effective date are located after the Standard, and
10、 are preceded by a SUPERSEDED REQUIREMENTS notice. AUGUST 1, 2013 UL 331 tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL AUGUST 1, 2013 UL 331 tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DIST
11、RIBUTION WITHOUT PERMISSION FROM UL FEBRUARY 25, 2008 (Title Page Reprinted: August 1, 2013) 1 UL 331 Standard for Strainers for Flammable Fluids and Anhydrous Ammonia The rst edition was titled Standard for Strainers for Hazardous Fluids. First Edition March, 1957 Second Edition October, 1971 Third
12、 Edition March, 1974 Fourth Edition September, 1977 Fifth Edition June, 1984 Sixth Edition June, 1993 Seventh Edition September, 1997 Eighth Edition February 25, 2008 This ANSI/UL Standard for Safety consists of the Eighth Edition including revisions through August 1, 2013. The most recent designati
13、on of ANSI/UL 331 as an American National Standard (ANSI) occurred on August 1, 2013. ANSI approval for a standard does not include the Cover Page, Transmittal Pages, Title Page, or effective date information. Comments or proposals for revisions on any part of the Standard may be submitted to UL at
14、any time. Proposals should be submitted via a Proposal Request in ULs On-Line Collaborative Standards Development System (CSDS) at http:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor electronic copy of a Standard should be altered in any way. All of ULs Standards and all co
15、pyrights, ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2013 UNDERWRITERS LABORATORIES INC. ANSI/UL 331-2013UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL AUGUST 1, 2013 STRAI
16、NERS FOR FLAMMABLE FLUIDS AND ANHYDROUS AMMONIA - UL 331 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .4 2 Components 4 3 Units of Measurement .5 4 Undated References 5 CONSTRUCTION 5 Ge
17、neral .5 6 Capacity .5 7 Materials .9 8 Bodies and Covers .10 9 Stuffing Boxes .11 10 Springs 12 PERFORMANCE 11 General 12 12 Tests On Synthetic-Rubber Parts .12 13 Deformation and External-Leakage Test .13 14 Hydrostatic-Strength Test 14 15 Element-Collapse Test 15 16 Pressure-Drop Test Strainers f
18、or Oil Burners .15 17 Clogging Test Strainers for Oil Burners 17 18 10-Day Moist Ammonia-Air Stress Cracking Test .20 MANUFACTURING AND PRODUCTION TESTS 19 General 20 MARKING 20 General 21 SUPPLEMENT SA - NON-POTABLE WATER STRAINERS Supplement SA added August 1, 2013 SA1 Scope SA1 SA2 Materials .SA1
19、 SA3 Performance SA2 SA4 Manufacturing and Production Tests .SA2 SA5 Marking SA2 AUGUST 1, 2013 STRAINERS FOR FLAMMABLE FLUIDS AND ANHYDROUS AMMONIA - UL 331 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 These req
20、uirements cover complete, self-contained strainer or lter assemblies intended for use with designated ammable uids and anhydrous ammonia (fertilizer grade) in residential and commercial fuel-burning, dispensing, and handling facilities. Although these devices are designated strainers, they may be ei
21、ther strainers or lters according to the common terminology of the industry. 1.2 The term ammable uids as used in this standard means fuel oil, gasoline, kerosene, and similar petroleum products, liqueed petroleum gas (LP-Gas), and manufactured and natural fuel gas. 1.3 These requirements do not cov
22、er the following: a) Strainers for handling liquids under cryogenic conditions; b) Strainers for marine use; c) Strainers for automotive fuel lines; d) Strainers for handling refrigerants; e) Strainers for use in such facilities as chemical, petrochemical, petroleum, and utility power plants; and f)
23、 Strainers for use in uid-power (hydraulic and pneumatic) applications. 1.4 Requirements for non-potable water strainers are covered in Supplement SA. 1.4 added August 1, 2013 2 Components 2.1 Except as indicated in 2.2, a component of a product covered by this standard shall comply with the require
24、ments for that component. 2.2 A component is not required to comply with a specic requirement that: a) Involves a feature or characteristic not required in the application of the component in the product covered by this standard, or b) Is superseded by a requirement in this standard. 2.3 A component
25、 shall be used in accordance with its rating established for the intended conditions of use. 2.4 Specic components are incomplete in construction features or restricted in performance capabilities. Such components are intended for use only under limited conditions, such as certain temperatures not e
26、xceeding specied limits, and shall be used only under those specic conditions. AUGUST 1, 2013 STRAINERS FOR FLAMMABLE FLUIDS AND ANHYDROUS AMMONIA - UL 331 4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 3 Units of Measurement 3.1 If a valu
27、e for measurement is followed by a value in other units in parentheses, the rst stated value is the requirement. 4 Undated References 4.1 Any undated reference to a code or standard appearing in the requirements of this standard shall be interpreted as referring to the latest edition of that code or
28、 standard. CONSTRUCTION 5 General 5.1 A strainer shall include all of the components necessary for its intended function and installation, and shall be furnished as a complete assembly. 5.2 The construction of a strainer shall be such that parts can be reassembled in the intended manner after being
29、dismantled to the extent needed for servicing. 5.3 A strainer shall be constructed so that, when in its intended operating position, any air trapped within will not reduce the rate of liquid ow or the effective strainer element capacity. 5.4 A strainer employing a strainer element intended to be cle
30、aned or replaced shall permit the removal of the element without disconnecting piping. 5.5 A strainer element shall be constructed so that joints or seals required to prevent uid bypass of the element will be maintained. 5.6 A strainer shall be constructed so that, when the screen or lter element is
31、 removed for cleaning, all foreign matter (sediment and dirt) will be removed or can be removed without the probability of any foreign matter being deposited in the outlet side of the strainer. 6 Capacity 6.1 A strainer that is intended to protect the smallest orice in oil burning equipment shall co
32、mply with the requirements in this section. Exception: This requirement does not apply to strainers intended for use in fuel oil transfer or recirculating piping systems. 6.2 A strainer element of the wire cloth, perforated, or plate type shall have a maximum orice (diameter) size or plate separatio
33、n of: a) 0.027 inch (0.69 mm) if the strainer is intended for use with No. 1 or 2 grade fuel oil and b) 0.056 inch (1.42 mm) if the strainer is intended for use with No. 4, 5, or 6 grade fuel oil service. FEBRUARY 25, 2008 STRAINERS FOR FLAMMABLE FLUIDS AND ANHYDROUS AMMONIA - UL 331 5UL COPYRIGHTED
34、 MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 6.3 Each strainer assembly is to be rated for capacity in terms of the maximum ring rate of the burner equipment as expressed in gallons of fuel oil per hour (3.79 l/hr). For strainers employing wire cloth o
35、r perforated screens, Figures 6.1 6.3 specify minimum areas of screen opening based upon the grade of fuel oil used and the ring rate of the equipment to be served. This is generated text for gtxt. Figure 6.1 Strainer area for No. 1 grade fuel oil NOTES 1) Fuel oil as designated by Specication for F
36、uel Oils, ANSI/ASTM D396-89 : 2) 1 in 2 = 6.45 cm 2 : 3) 1 Gallon = 3.79 l FEBRUARY 25, 2008 STRAINERS FOR FLAMMABLE FLUIDS AND ANHYDROUS AMMONIA - UL 331 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL Figure 6.2 Strainer area for No. 2 gr
37、ade fuel oil NOTES 1) Fuel oil as designated by Specication for Fuel Oils, ANSI/ASTM D396-89 : 2) 1 in 2 = 6.45 cm 2 : 3) 1 Gallon = 3.79 l Figure 6.3 Strainer area for Nos. 4, 5, 6 grade fuel oils NOTES 1) Fuel oils as designated by Specication for Fuel Oils, ANSI/ASTM D396-89: 2) 1 in 2 = 6.45 cm
38、2 : 3) 1 Gallon = 3.79 l FEBRUARY 25, 2008 STRAINERS FOR FLAMMABLE FLUIDS AND ANHYDROUS AMMONIA - UL 331 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 6.4 The selection of capacity ratings based on ring rates versus open or free area for
39、various grades of fuel oil also provides for low initial pressure losses or drops through the strainer assembly when clean. 6.5 The capacity of each size and type of element is to be determined. If possible, this is to be accomplished by calculation as outlined in 6.6 and 6.7 for wire cloth and perf
40、orated types. Elements other than these, such as lter elements of felt, cotton waste, ceramics, and the like, are to be subjected to the Clogging Test Strainers for Oil Burners, Section 17, to: a) Establish ratings by comparison to established properties of wire cloth or perforated screens and b) De
41、termine that the lter-type element will not pass particles that will be retained by the standard wire-mesh strainer element used for comparison. 6.6 A wire-cloth element has an open area equal to the total area of the cloth minus the area covered by seams, ribs, and supports multiplied by the screen
42、 factor. The screen factor is that percentage of open area of the cloth to the whole area. If the screen factor is unknown, it may be calculated as follows: in which: N is the number of wires in warp per inch, D is the diameter of wire in warp in inches, n is the number of wires in the shoot per inc
43、h, and d is the diameter of wire in the shoot in inches. Note: 1 inch = 25.4 mm 6.7 A perforated element has an open area equal to the total number of openings multiplied by the area of each opening minus the area covered by seams, ribs, and supports. 6.8 The effective area of a perforated element t
44、hat includes a wire-cloth insert is considered to be the smaller of the two areas determined by 6.6 and 6.7. FEBRUARY 25, 2008 STRAINERS FOR FLAMMABLE FLUIDS AND ANHYDROUS AMMONIA - UL 331 8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 7 M
45、aterials 7.1 A part in contact with the uid to be handled shall be resistant to the action of such uid. 7.2 Zinc, copper, and copper-base alloys, such as brass, that are subject to rapid destructive action by ammonia in the presence of water shall not be used for anhydrous ammonia service. 7.3 Excep
46、t as indicated in 7.4 and 7.5, uid-containing parts other than a seal ring or a gasket shall have a melting point (solidus temperature) of not less than 950F (510C) and an ultimate tensile strength of not less than 10,000 psig (69 MPa) at 400F (204C). Exception: For a strainer for an oil burner, an
47、oil-containing part, other than a base (head) unit, a melting point (solidus temperature) less than 950F (510C) is allowed to be installed if: a) The part is protected by a fusible-link shut-off valve with a temperature rating of not more than 350F (177C). The fusible-link shut-off valve shall compl
48、y with the Standard for Valves for Flammable Fluids, UL 842; and b) The part is suitable for exposure to the intended fuel and the part complies with the requirements of the Resistance to Impact Test, Mold Stress-Relief Distortion Test, in accordance with the Standard for Polymeric Materials Use in
49、Electrical Equipment Evaluations, UL 746C, with the following parameters: 1) With regard to the Resistance to Impact Test, the drop impact test shall be conducted utilizing a concrete oor or an equivalent nonresilient oor in lieu of a hardwood surface. 2) With regard to the Resistance to Impact Test, the ball impact test shall be conducted with the impact requirements of 6.8 J (5.0 ft-lbs). 3) With regard to the Mold Stress-Relief Distortion Test, the part is to b
