1、ANSI/MSS SP-138-2014 Quality Standard Practice for Oxygen Cleaning of Valves and Fittings Standard Practice Developed and Approved by the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 127 Park Street, NE Vienna, Virginia 22180-4602 Phone: (703) 281-6613 Fax: (703) 28
2、1-6671 E-mail: standardsmss-hq.org www.mss-hq.org MSS STANDARD PRACTICE SP-138i This MSS Standard Practice was developed under the consensus of the MSS Technical Committee 407 and the MSS Coordinating Committee. In addition, this Standard Practice was approved by an ANSI/MSS Consensus Committee and
3、ANSI as an American National Standard. The content of this Standard Practice is the resulting efforts of competent and experienced volunteers to provide an effective, clear, and non-exclusive standard that will benefit the industry as a whole. This MSS Standard Practice describes minimal requirement
4、s and 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, or use of products not conforming to the Standard Practice. Mandatory conformance to this Standard Prac
5、tice is established only by reference in other documents such as a code, specification, sales contract, or public law, as applicable. MSS has no power, nor does it undertake, to enforce or certify compliance with this document. Any certification or other statement of compliance with the requirements
6、 of this Standard Practice shall not be attributable to MSS and is solely the responsibility of the certifier or maker of the statement. “Unless indicated otherwise within this MSS Standard Practice, other standards documents referenced to herein are identified by the date of issue that was applicab
7、le to this Standard Practice at the date of approval of this MSS Standard Practice (see Annex A). This Standard Practice shall remain silent on the validity of those other standards of prior or subsequent dates of issue even though applicable provisions may not have changed.” By publication of this
8、Standard Practice, no position is taken with respect to the validity of any potential claim(s) or of any patent rights in connection therewith. MSS shall not be held responsible for identifying any patent rights. Users are expressly advised that determination of patent rights and the risk of infring
9、ement of such rights are entirely their responsibility. In this Standard Practice, all text, notes, annexes, tables, figures, and references are construed to be essential to the understanding of the message of the standard, and are considered normative unless indicated as “supplemental”. All appendi
10、ces, if included, that appear in this document are construed as “supplemental”. Note that supplemental information does not include mandatory requirements. The SI (metric) units and U.S. customary units in this Standard Practice are regarded separately as the standard; each should be used independen
11、tly of the other. Combining or converting values between the two systems may result in non-conformance with this Standard Practice. This Standard Practice has been substantially revised from the previous 2009 edition. It is suggested that if the user is interested in knowing what changes have been m
12、ade, that direct page by page comparison should be made of this document and that of the previous edition. Non-toleranced dimensions in this Standard Practice are nominal unless otherwise specified. Excerpts of this Standard Practice may be quoted with permission. Credit lines should read Extracted
13、from ANSI/MSS SP-138-2014 with permission of the publisher, Manufacturers Standardization Society of the Valve and Fittings Industry. Reproduction and/or electronic transmission or dissemination is prohibited under copyright convention unless written permission is granted by the Manufacturers Standa
14、rdization Society of the Valve and Fittings Industry Inc. All rights reserved. Originally Approved: April 2008 Originally Published: May 2009 Current Edition Approved by MSS: July 2013 Current Edition Approved by ANSI: July 2014 Current ANSI/MSS Edition Published: December 2014 MSS is a registered t
15、rademark of Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Copyright , 2014 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. MSS STANDARD PRACTICE SP-138ii FOREWORD This Standard Practice was developed by a cooperativ
16、e effort of representatives of manufacturers who produce oxygen clean valves and fittings. It is based on the best practice current at this time and on the collective experience of the industry. In 2013, this Standard Practice was revised by MSS and subsequently ANSI-approved as an American National
17、 Standard in 2014. This process involved an ANSI/MSS Consensus Committee that was composed of a diverse volunteer group of industry stakeholders with a material interest in the topic of this Standard Practice. MSS STANDARD PRACTICE SP-138iii TABLE OF CONTENTS SECTION PAGE PURPOSE . 1 1 SCOPE . 1 2 G
18、ENERAL REQUIREMENTS . 1 3 CLEANING . 1 4 INSPECTION AND ACCEPTANCE CRITERIA 2 5 POST CLEAN ASSEMBLY AND TESTING . 3 6 PACKAGING . 4 7 MARKING 4 ANNEX A Referenced Standards and Applicable Dates . 5 MSS STANDARD PRACTICE SP-1381 PURPOSE The purpose of this Standard Practice is to provide standard met
19、hods for processing valves and fittings intended to be used for Oxygen Service. The proper combination of methods depends upon the part, its method of manufacture, and the types of contamination present. It is recommended that prior to implementation of this Standard Practice, an agreement be reache
20、d between the purchaser and the product manufacturer as to the appropriate methods to be used for the product to be cleaned. 1. SCOPE 1.1 This Standard Practice outlines the general requirements for cleaning, inspection, testing, and packaging of valves and fittings intended to be used for Oxygen se
21、rvice. 1.2 Proper design and material compatibility for Oxygen systems is outside the scope of this Standard Practice. 2. GENERAL REQUIREMENTS 2.1 Any cleaning agent used must be compatible with the material of the component being cleaned. 2.2 Chloride-free cleaning agents shall be used on stainless
22、 steel. See Section 2.8 for additional guidance. 2.3 The handling, storage, and use of all chemicals shall be according to the instructions given in their material safety data sheets (MSDS). 2.4 Used cleaning solutions shall be disposed of in accordance with appropriate hazardous waste regulations.
23、2.5 Parts of assemblies shall be disassembled and separately cleaned before assembly can render any surface inaccessible to cleaning and inspection. 2.6 Any special tests required for assemblies that employ media that are incompatible with oxygen shall be performed before disassembly for cleaning. 2
24、.7 Cleaning, inspection, post-clean testing, and packaging shall be conducted by properly trained and qualified personnel, knowledgeable of this Standard Practice and of the hazards and potential ignition sources in oxygen systems. 2.8 For additional guidance on oxygen cleaning, refer to: 2.8.1 ASTM
25、 G93, Cleaning Methods and Cleanliness Levels for Material and Equipment Used in Oxygen-Enriched Environments 2.8.2 ASTM G127, Standard Guide for the Selection of Cleaning Agents for Oxygen Systems 2.8.3 CGA G-4, Oxygen 2.8.4 CGA G-4.1, Cleaning Equipment for Oxygen Service 3. CLEANING 3.1 Cleaning
26、must ensure the removal of contaminants(1)that can cause mechanical malfunction, fire, or explosion. Cleaning per this Standard Practice will effectively remove rust, loose scale, dirt, weld splatter, particles, grease and oil. 3.2 No single cleaning process will remove all potential ignition source
27、s. Several cleaning methods will need to be employed depending upon the type of contamination present to pass the post-clean inspection. QUALITY STANDARD PRACTICE FOR OXYGEN CLEANING OF VALVES AND FITTINGS NOTE: (1) The term contaminant refers to unwanted molecular, particulate, or chemical matter t
28、hat could adversely affect or degrade the operation, life, or reliability of the system(s) or component(s) where it resides (e.g., amount of contamination; process or condition of being contaminated). MSS STANDARD PRACTICE SP-1382 3.3 Before detailed cleaning of the parts, heavy oil or grease contam
29、ination must be pre-cleaned using alkaline cleaner or detergent. Use brushes as necessary to assist the degreasing action. Residual detergent is to be rinsed from the surface with clean water before proceeding to precision cleaning methods. Mixing of cleaning agents can create chemicals that are haz
30、ardous to health and the environment. 3.4 Mechanical Cleaning 3.4.1 Mechanical cleaning includes grit blasting, wire brushing, and grinding to remove visible rust, varnish, paint, weld slag, and heavy mill scale. It shall be done before proceeding with solution cleaning. If repeated because of a fai
31、led inspection, solution cleaning also needs to be repeated. Grit or shot blasting cleaning of stainless steel parts shall be done with stainless grit or shot that has not been previously used. Shot and grit blasting equipment should be “dedicated” to stainless steel mechanical cleaning solutions. 3
32、.4.2 Blasting grit shall be glass bead, sand, or non-metallic, and shall not be reused for oxygen cleaning. 3.4.3 Carbon steel wire brushes shall not be used to clean stainless steel or aluminum. In addition, any wire brush used on carbon steel shall not be used on stainless steel or aluminum. 3.4.4
33、 After mechanical cleaning, all loose dirt and debris shall be completely removed from the part by vacuum, brushing, blowing with clean, dry, oil-free air or nitrogen, or by flushing with clean water before proceeding with solution cleaning. 3.5 Solution Cleaning 3.5.1 All equipment used in the clea
34、ning process shall be clean and free of contaminants. Clean gloves shall be worn when handling clean parts. Work surfaces shall be covered with a clean polyethylene plastic sheet, and the surrounding environment shall be dust free. 3.6 Detergent Cleaning 3.6.1 Mild detergent is used to clean nonmeta
35、llic and aluminum parts. Spray and/or immerse the part in a detergent solution. Assist cleaning action by brushing to aid in contaminant removal. 3.7 Alkaline Cleaning 3.7.1 Corrosion-resistant and PTFE, or Polytetrafluoroethylene, type materials are cleaned with an alkaline cleaning agent. Immerse
36、items in a solution of alkaline cleaner. Assist cleaning action by vigorously agitating the bath or by brushing. 3.8 Acid Cleaning 3.8.1 Acid cleaning is used for non-welded stainless steel parts and other acid resistant materials. Immerse parts in acidic cleaning solution and assist cleaning action
37、 by vigorously agitating the bath or brushing with suitable brushes. 3.9 Acid Pickling 3.9.1 Acid pickling is used to remove minor rust particles, weld slag, and weld discoloration. Place newly welded stainless steel parts in a pickling bath of 3 to 5 percent hydrofluoric and 15 to 20 percent nitric
38、 acid solution for 3 to 5 minutes. Brush with stainless steel brush as necessary to remove weld discoloration. 3.10 After each cleaning process and before employing a different cleaning method, thoroughly rinse, spray or immerse the part in deionized, distilled, filtered water to remove all the clea
39、ning agent. See Section 2.8 for additional guidance. 3.11 After rinsing, blow-dry the parts with filtered, dry, oil-free air or nitrogen. See Section 2.8 for additional guidance. 4. INSPECTION AND ACCEPTANCE CRITERIA 4.1 Note that no single inspection method is sufficient to verify that the part is
40、adequately cleaned for Oxygen Service. A combination of methods is necessary to establish that the cleaning process effectively removes all possible contamination. MSS STANDARD PRACTICE SP-1383 4.2 Parts are to be inspected individually before assembly. If inspection reveals the presence of any cont
41、aminants, the item shall be re-cleaned and re-inspected until it successfully passes the acceptance criteria. 4.3 White Light Inspection 4.3.1 Look at all surfaces of the part under bright white light to detect visible particulate matter, filings, chips, loose rust, mill scale, weld splatter, paint,
42、 and oil or grease film. 4.3.2 Direct artificial lighting using white flood or halogen lamps shall be used to fully illuminate the surface to be inspected. Light intensity shall be adjusted to avoid excessive reflection that will detract from the inspection. 4.3.3 Any visible moisture, residual clea
43、ning agent, or the above particulate matter is not permissible, and must be removed. 4.4 Ultraviolet (UV) Inspection 4.4.1 Inspection shall be done in a dark room or enclosure that is free from any other light except UV. 4.4.2 The UV light source should be a minimum of 100 watts and emit a minimum i
44、ntensity of 800 microwatts per square centimeter when measured at a distance of 15 in. (380 mm) from the filter face. Note that it is important to regularly check the lamp as bulbs lose their intensity over time. 4.4.3 The UV lens filter shall have a wavelength between 3,200 to 3,800 angstroms. 4.4.
45、4 Not all oil and grease are fluorescent, so this inspection technique must be used in conjunction with a visual inspection. 4.4.5 Any visible fluorescents shall be removed by wiping with a clean, lint-free cloth, blowing with oil-free air or nitrogen, or if necessary, re-cleaned until fluorescent i
46、s no longer visible. 4.5 Wipe Test 4.5.1 Use this method for inspection of inaccessible surfaces or very large items. The area covered per wipe shall be approximately 1 sq ft (0.09 sq m). 4.5.2 The wipe test is valid for smooth surfaces that do not abrade and disintegrate the wipe. 4.5.3 Wipe the su
47、rface with clean white paper, white paper coffee filter, unbleached cloth, or for very small holes, a cotton swab. A new wiping medium should be used for each area examined. 4.5.4 After wiping, examine the surface of the wipe under both bright white light and UV light. 4.5.5 No visible contamination
48、 is permissible other than a light oxide film (rust). 4.6 Solvent Inspection 4.6.1 Solvent inspection is to be used for surfaces that are not visible and are not hand accessible such as deep, small diameter bores. 4.6.2 Use approximately 3.4 oz (100 ml) of solvent per 1 sq ft (0.09 sq m) of area. 4.
49、6.3 Flush inspected area with clean solvent. Collect and inspect the solvent against a clean sample of unexposed solvent using UV. Visible evidence of contamination is not allowed. 4.6.4 Collected solvent should be poured through a clean white paper coffee filter and the filter paper inspected under bright white light for contamination. Visible evidence of contamination is not allowed. 5. POST CLEAN ASSEMBLY AND TESTING 5.1 Immediately after acceptance, cleaned parts shall be assembled. Delayed assembly requires the cleaned parts to be protected by packaging and controlled storage to pr
