ASTM D3698-2004 Standard Practice for Solvent Vapor Degreasing Operations《溶剂蒸气脱脂操作方法的标准规程》.pdf

1、Designation: D 3698 04Standard Practice forSolvent Vapor Degreasing Operations1This standard is issued under the fixed designation D 3698; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in paren

2、theses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice recommends work practices for conven-tional vapor degreasing operations utilizing any solvent orsolvent blend that has been categorized

3、 as nonflammable.1.2 This practice is not intended for use in vapor degreasingoperations utilizing flammable (low flash point) solvents or invapor degreasing operations utilizing enclosed (sealed, air-tight) equipment. For these non-applicable operations, usersshould consult the solvent or equipment

4、 supplier for additionalinformation.1.3 The values given in inch-pound units are to be regardedas the standard. The values stated in parentheses are forinformation only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility o

5、f the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2110 Test Method for pH of Water Extractions of Halo-genated Organic Solvents and Their AdmixturesD 29

6、42 Test Method for Total Acid Acceptance of Haloge-nated Organic Solvents (Nonreflux Methods)D 4276 Practice for Confined Area EntryD 4579 Practice for Handling an Acid Degreaser or Still2.2 Government Documents:340 CFR Part 63.460-469 U.S. EPA, National EmissionStandards for Halogenated Solvent Cle

7、aning29 CFR Part 1910 U.S. Department of Labor, OccupationalSafety and Health Standards2.3 Other Documents:Threshold Limit Values for Chemical Substances and Physi-cal Agents, ACGIH Industrial Ventilation, ACGIH4NFPA 704 Identification System for Fire Hazards of Mate-rials, National Fire Protection

8、Association53. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 emergencyany occurrence that may result in animmediate hazard to health including exposures resulting from,but not limited to, equipment failure, rupture of containers, orfailure to control equipment.3.1.2 hazardous o

9、perationany procedure or activitywhere a release of the solvent or the decomposition products ofthe solvents might be expected to result in a hazard to health.3.1.3 nonflammable solvent(s)as used herein, is a solventor solvent mixture having a NFPA flammability hazard ratingof 1 or lower (as determi

10、ned by NFPA 704), intended for use invapor degreasing operations.3.1.4 solvent vapor degreasera solvent and corrosion-resistant tank with a heated solvent reservoir or sump at thebottom, a condensing means near the top, and freeboard abovethe condensing means, in which sufficient heat is introduced

11、toboil the solvent and generate hot solvent vapor. Because the hotvapor is heavier than air, it displaces the air and fills the tankup to the condensing zone. The hot vapor condenses on thecooled condensing means, thus maintaining a fixed vapor leveland creating a thermal balance.3.1.5 solvent vapor

12、 degreasing operationsthe process bywhich materials are immersed in vapors of boiling liquids forthe purpose of cleaning or altering their surfaces, and aresubsequently removed from the vapors, drained and dried in asolvent vapor degreaser.4. Significance and Use4.1 This practice is intended for use

13、 by employers indeveloping their own specific operation standards for solventvapor degreasing operations.1This practice is under the jurisdiction of ASTM Committee D26 on Haloge-nated Organic Solvents and Fire Extinguishing Agents and is the direct responsi-bility of Subcommittee D26.02 on Vapor Deg

14、reasing.Current edition approved Dec. 1, 2004. Published December 2004. Originallyapproved in 1979. Last previous edition approved in 1999 as D 3698 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMSta

15、ndards volume information, refer to the standards Document Summary page onthe ASTM website.3Code of Federal Regulations, available from U.S. Government Printing Office,Washington, DC 20402.4Available from American Conference of Governmental Industrial Hygienists,Inc., 1330 Kemper Meadow Dr., Suite 6

16、00, Cincinnati, OH 45240.5Available from National Fire Protection Association, 1 Batterymarch Park,Quincy, MA 022699101.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 Certain vapor degreasing operations are subject to therequire

17、ments of the National Emission Standards for Haloge-nated Solvent Cleaning (Halogenated Solvent Cleaner NES-HAP) as found in 40 CFR Part 63, Subpart T. The determina-tion of the applicability of these, or any additionalrequirements is the responsibility of the user.4.3 This practice is not intended

18、to address all of therequirements contained in the Halogenated Solvent CleanerNESHAP. Development and implementation of training pro-grams, recordkeeping, and other additional requirements of theNESHAP are the responsibility of the user.5. Exposure Limit5.1 No employee may be exposed to any of the s

19、olventsutilized in vapor degreasing operations covered by this sectionin excess of either the OSHA Permissible Exposure Limits(PEL), the ACGIH Threshold Limit Value (TLVt), or anymanufacturers recommended exposure limit.6. System Location and Design6.1 Location:6.1.1 Degreasers shall be placed in a

20、room having ventila-tion adequate to maintain operator exposure below the appro-priate exposure limit.6.1.2 A degreaser shall be installed so that it is not affectedby drafts from sources such as windows, doors, fans, unitheaters, ventilators, or adjacent spray booths. Normal aircirculation (at velo

21、cities not exceeding 50 ft (15.24 m)/min) isrecommended and should not be confused with direct draftssuch as those listed in the preceding sentence. Drafts should bediverted from the top of the degreaser by the use of baffleslocated on the windward side of the degreaser.6.1.3 No degreaser shall be i

22、nstalled in areas where solventvapors may reach open flames or high-temperature surfacesabove 350F (176C). Solvent degreasing equipment shall notbe installed in the proximity of welding and heat treatingoperations or space heaters unless adequate ventilation of thedegreaser or other means are provid

23、ed to prevent solvent fumesfrom contacting the high-temperature source.6.1.4 Gas-heated degreasers (provided with natural draftventilation of combustion tube) shall not be located in an areawhere the general mechanical exhaust system produces nega-tive pressure, unless positive exhausting of combust

24、ion prod-ucts by mechanical means is provided.6.2 Design:6.2.1 The level of vapors below the top edge of thedegreaser (freeboard) shall at a minimum be a 1.0 ratio ofheight to width.6.2.2 All degreasers shall have durable covers which shallbe secured in a closed position when degreasing operations a

25、renot occurring. Sliding covers, which allow partial closureduring degreasing operations are preferred.6.2.3 Where gas is used as a fuel for heating, the combus-tion chamber of the degreaser shall be of tight construction,except for such openings as the exhaust flue, and those that arenecessary for

26、supplying air for combustion. Flues shall be ofcorrosion-resistant construction and shall extend to the outsideair. If mechanical exhaust is used on the flue, there shall beprovision for outside fresh make-up air. If nonmechanicalexhaust is used on the flue, a back draft diverter shall be used.Gas b

27、urners shall be provided with safety protection to provideshut down if the pilot or igniter fails.6.2.4 Heating elements shall be so designed and maintainedthat their surface temperature will not cause the solvent ormixture to decompose or break down.6.2.5 New solvent vapor degreasers or solvent sti

28、lls of morethan 4 ft2of vapor area shall be equipped with suitableclean-out or sludge doors located at the bottom of the boilingsump and any other sump having an area of more than 4 ft2(0.37 m2). These doors shall be designed and gasketed so thatthere will be no leakage when they are closed.6.2.6 Fl

29、oors and platforms around degreasers shall be pre-vented from becoming slippery both by the original type ofconstruction and by frequent cleaning. They shall be firm,sound, and of the design and construction to minimize thepossibility of tripping. Railing requirements for platformsappear in 29 CFR 1

30、910.23(c).6.2.7 When an open top degreaser is located in a pit belowfloor level, the elevation of the top of the degreaser shall be aminimum of 42 in. (1066 mm) above the floor level or theoperating level or else a 42-in. (1066-mm) railing must beprovided in accordance with 29 CFR 1910.23(c)(3) and(

31、e)(1). Pit ventilation shall be designed to provide a minimumof two air changes per minute whenever a degreaser is installedin a pit more than 18 in. (457 mm) deep.6.2.8 Degreasers shall be equipped with means to preventsolvent vapors from overflowing, such as a vapor level controldevice (vapor safe

32、ty thermostat) sensitive enough to shut offthe heat input if the solvent vapor level rises above the primarycondensing coils.6.2.8.1 The vapor safety thermostat is typically set at atemperature 20 to 30 % below the boiling point of the solvent(based on the boiling point in F) except for very low boi

33、lingsolvents (for example, methylene chloride). For these solvents,the vapor safety thermostat should be set at ambient tempera-ture +10F, but never higher than 100F (38C). Recom-mended temperatures for vapor safety thermostat settings canbe determined fromAppendix X1, or from the solvent supplier.6

34、.2.9 Degreasers shall be equipped with safety devices inthe boiling sump that can shut off the heat input if the solventlevel drops too close to the heating coils (sump level controldevice) or if the solvent becomes too contaminated (sumpsafety thermostat).6.2.9.1 A sump level control device is desi

35、gned to preventheat input unless there is adequate solvent in the boiling sump.Such devices may be mechanical (liquid level sensor) orthermostatic (liquid level safety thermostat). The liquid levelsensor should interrupt heat input if the liquid level is less than2 in. above the heating coils. Liqui

36、d level safety thermostats,used on electrically heated degreasers, are attached to the uppersurface of the heating coil with a maximum recommendedsetting of 20F above the boiling point of the solvent.6.2.9.2 Degreasers should also be equipped with a sumpsafety thermostat immersed in the boiling liqu

37、id. If the de-greaser is equipped with an auxiliary still, then the degreasersump safety thermostat should be set at the temperaturecorresponding to 25 % oil contamination (see 7.4.2.1). TheD3698042sump safety thermostat in the auxiliary still should then be setat the temperature corresponding to 25

38、 % oil concentration ifthe unit is electrically heated. However, the sump safetythermostat in the auxiliary still can be set at the temperaturecorresponding to approximately 70 % oil concentration if theunit is indirectly heated by such means as steam. Recom-mended temperatures for the sump safety t

39、hermostat can bedetermined from Appendix X1, or from the solvent supplier.6.2.9.3 If reclamation of solvent will be conducted using thedegreasers boiling sump as the still sump, then the safetythermostat in the degreaser may be adjusted to the highersetting during that operation and then readjusted

40、to the tem-perature corresponding to 25 % oil concentration during nor-mal operation.6.2.10 Degreasers shall be equipped with a device to pre-vent heat input unless there is adequate cooling to ensuresufficient condensation of vapor in the degreaser.6.2.11 Degreasers of the spray type shall be equip

41、ped witha method that will prevent spray pump operation unless thesolvent vapors have reached normal operating levels.6.2.12 Steam-heated degreasers shall be equipped with“ popsafety valves” down-stream from any pressure control. Thepressure relief setting should be consistent with the solvent inuse

42、, and may be determined from Appendix X1, or from thesolvent supplier.6.2.13 Conveyorized degreasers shall be equipped with athermostat that will prevent work from being processed bystopping conveyorized operation unless the solvent vaporshave reached the normal operating levels.7. Degreaser Operati

43、ons Procedures7.1 Start-UpIn starting a vapor degreaser follow theprocedures enumerated sequentially where applicable:7.1.1 Turn on the cooling/condensing system coolant andcheck to ensure proper operation.7.1.2 Start air exhaust equipment, if any.7.1.3 Activate all safety control thermostats.7.1.4

44、Adjust solvent levels in all compartments as neces-sary.7.1.5 Check that all degreaser covers are in place duringheat-up as well as cool-down.7.1.6 Turn on the heat supply and adjust the settings asnecessary. Adjust the heat balance in the degreaser so that thelevel of the vapor remains constant. A

45、proper balance isachieved if solvent vapors are generated at the same rate theyare condensed by work entering the vapor zone and by thecondensers.7.1.7 Once the vapor level reaches the condensing coils,check to ensure the flow of condensed solvent through thewater separator and its return to proper

46、degreaser compart-ments.7.1.8 Check all gages and thermometers for proper opera-tion.7.1.9 Begin vapor degreasing of work items.7.1.10 Check condenser coolant flow and adjust coolantflow or temperature, or both, to maintain temperature to ensurethat the vapor line does not rise above the condenser a

47、nd tominimize condensation of moisture from the room air on thecondenser coils. Check that all coolant and heating lines arefree of leaks and the water separator is functioning properly toprevent contamination in the degreaser.7.2 DegreasingIn degreasing follow the procedures enu-merated:7.2.1 Do no

48、t allow work loads to exceed designed degreasercapacity. Work should not generally occupy more than 50 % ofthe open horizontal area of the machine unless the workpermits easy passage of vapor through or around it. Secure ahighly durable tag to each degreaser indicating the maximumweight and volume o

49、f a single load expressed in terms ofpounds per load and loads per hour.7.2.2 Place work loads, where necessary, in free-drainingnonporous baskets, trays, racks, and so forth, and position toeliminate solvent drag out.7.2.3 When working with cup-shaped parts or parts withcavities that may collect liquid, load the parts, and rotate ifnecessary, in a manner to facilitate complete drainage while inthe vapor zone.7.2.4 Do not allow the vertical rate of entry and withdrawalof work loads to exceed the maximum degreaser design, whichshould not exceed 11 ft/min (3.4 m/min