ASTM D4276-2002(2007) Standard Practice for Confined Area Entry《有限通道面积的标准规程》.pdf

1、Designation: D 4276 02 (Reapproved 2007)Standard Practice forConfined Area Entry1This standard is issued under the fixed designation D 4276; 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 par

2、entheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers recognized procedures necessary toprotect the health and safety of workers required to enterconfined spaces. These procedures

3、are particularly applicableto entry into the confined areas associated with the use ofhalogenated organic solvents.1.2 Confined areas addressed in this practice include, but arenot limited to: vapor degreasers, cold cleaning tanks, storagevessels, tank cars and trucks, van trailers, ships or barges,

4、 pitsor sumps, and unventilated rooms.1.3 This practice does not necessarily address entry into allconfined spaces nor does it address the decision strategyinvolved in requiring such entry.1.4 Although this practice describes specific safety steps tobe taken for entry into confined spaces, it is not

5、 intended topreclude the use of any additional measures that may bedeemed necessary for a particular situation.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safe

6、ty and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:CFR 1910.146 U.S. Department of Labor, OccupationalSafety and Health Standards, Permit-Required ConfinedSpaces3. Summary of Practice3.1 Confined area entry refers

7、 to the entering of any tank,vessel, sump, pit, duct, tank car, tank truck, van trailer, orenclosed space in which there has been, or may have beenchemicals, chemical vapors, or a lack of ventilation.4. Significance and Use4.1 Vapor inhalation is the primary hazard encountered inthe use of chlorinat

8、ed solvents. The greatest potential for overexposure to these solvent vapors occurs where the employee isexposed to the high concentrations of vapor that may be foundin confined areas. The seriousness of this hazard is oftenunderestimated by those performing this type of work.4.2 This practice is de

9、signed for use by employers indeveloping their own specific standards for vessel or confinedarea entry.4.3 Many of these areas are considered as permit-requiredconfined spaces as defined by OSHA (29 CFR 1910.146). Thedetermination of the applicability of these requirements is theresponsibility of th

10、e user.4.4 This practice represents the minimum requirements forentry into any confined area containing halogenated solvents.4.5 This practice does not address all of the requirementscontained in the OSHAconfined spaces standard. Developmentand implementation of training programs, recordkeeping, and

11、other additional requirements of the OSHA standard are theresponsibility of the user.5. Procedure5.1 All personnel working in confined areas must be prop-erly trained in safe entry and rescue procedures. They musthave a working knowledge and understanding of the hazardsthat may exist.5.2 Entry Permi

12、tEntry into confined areas must be bywritten entry permit, issued by the responsible supervisor orother qualified person. The purpose of the entry permit is toensure that a checklist of precautions has been reviewed priorto entry. This permit is an authorization, and approval inwriting certifying th

13、at all existing hazards have been evaluatedand necessary protective measures have been taken to ensurethe safety of the worker. The permit should be valid for alimited time only, (usually an 8 or 10-h shift) and issuance ofa new permit required in the event of any job interruption orany indication o

14、f changes in job conditions. Issuance of theentry permit must address all of the following considerations.5.3 Area Preparation:5.3.1 IsolationAll process lines exiting or entering theconfined area must be disconnected, capped off, and blinded.Closing of valves alone is not adequate protection.5.3.2

15、LockoutPumps or any other mechanical or electricalequipment (particularly conveyors), connected to the confinedarea, are to be locked out by locking the main electrical switchin the “OFF” position.1This practice is under the jurisdiction of ASTM Committee D26 on Haloge-nated Organic Solvents and Fir

16、e Extinguishing Agents and is the direct responsi-bility of Subcommittee D26.05 on Industrial Hygiene.Current edition approved Feb. 1, 2007. Published May 2007. Originallyapproved in 1984. Last previous edition approved in 2002 as D 4276 02 .1Copyright ASTM International, 100 Barr Harbor Drive, PO B

17、ox C700, West Conshohocken, PA 19428-2959, United States.TABLE 1 SAMPLE PERMIT Tank or Confined Area Entry PermitNOTE 1This permit is valid only between the hours noted. Any change of supervisor, workman, or working conditions will void this permit.D 4276 02 (2007)25.3.3 CleaningThe space must be cl

18、eared, flushed, orpurged of hazardous materials to the extent practical. Thisshould be followed, where practical, by cleaning with water,steam, or other suitable materials.5.3.4 VentilationA system for positive ventilation must beprovided, prior to and during the entire entry period, throughthe use

19、of fans, portavents, air movers, or by adequate naturaldrafts.5.4 Atmospheric TestingThe confined area must be testedfor the following prior to and during any entry:5.4.1 Oxygen ContentThe oxygen content must be be-tween 19.5 and 22.0 % in all levels of the confined area.5.4.2 FlammabilityThe atmosp

20、here must be nonexplosive(less than 10 % of the lower flammable limit).5.4.3 ToxicityThe atmosphere must be tested to ensure theabsence of toxic concentrations of vapors.5.5 Personal Protective EquipmentPersonal protectiveequipment is not an adequate substitute for safe workingconditions, adequate v

21、entilation, or safe working practices.5.5.1 Personal protective equipment can include, but is notlimited to: approved respirator, hard hat, safety glasses orsafety goggles, gloves, and long-sleeved shirts.5.6 Area Safety EquipmentAny person entering the con-fined area must be fitted with a safety ha

22、rness and lifeline. Thelifeline must be secured outside the entrance.5.6.1 Where entry into the confined area must be madethrough a top opening, a hoisting device or other effectivemeans must be provided to lift employee out of the space.5.6.2 Ladders must be in place for entrances and exits whereth

23、e drop or climb involves a depth of more than 3 ft.5.6.3 Self-contained breathing apparatus or supplied-air res-pirators must be available at the confined area entrance. Thesedevices must be worn if testing finds the toxicity level to beabove the OSHA limits.5.7 AttendantA second person must be avai

24、lable at thearea entrance and in sight of the person inside at all times. Hemust be equipped with proper safety equipment and adequatecommunications equipment for summoning additional help ifnecessary (for example, two-way radio, whistle, etc.). Underno conditions should this attendant enter the enc

25、losed areaunless others are standing by. If the observer is required toleave his post, the person inside the enclosed space must comeout.5.8 ToolsApproved low-voltage electrical equipmentmust be used where the atmosphere in the confined area maycontain flammable vapors or where the atmosphere couldc

26、ontain solvent vapors within their flammable limits. Allelectrical circuits must be equipped with a ground-fault inter-ruptor.5.9 LabelingEntrances to confined areas must be posted,identifying the area as a confined area and that a permit isrequired for entry. During the work, when there is more tha

27、none entrance to the confined area, signs indicating that workersare inside, posted at each entrance, are necessary.6. Testing Procedures6.1 The tests required prior to entry into a confined areamake use of specialized equipment.6.1.1 Oxygen Content2Use a portable instrument thatanalyzes directly fo

28、r oxygen irrespective of the solvent vaporspresent in the air.6.1.2 FlammabilityMeasurement of the flammability ofthe atmosphere may be done using a combustible gas indica-tor.36.1.3 ToxicityIf the prior contents of the vessel are known,the remaining concentrations of those materials may be deter-mi

29、ned as follows: for methylene chloride, tri-chloroethylene,1,1,1-trichloroethane, and perchloro-ethylene, use gas-detectortubes found in the NIOSH certified-equipment list.4A cali-brated halide meter5may be used as an alternative. Fortrichlorotrifluoroethane, use either a portable flame-ionizationga

30、s chromatograph6or a portable IR analyzer.77. Keywords7.1 confined areas; confined spaces; halogenated solventsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advise

31、d that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either re

32、approved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If y

33、ou feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individua

34、l reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).2Model OX230 Audible Alarm Oxygen Monitor, National Mine Service Co.,O

35、akdale, PA, or equivalent.3Explosimeters (registered trademark), Mine Safety Appliances, or equivalent.4Available from the National Institute for Occupational Safety and Heatlh, 5600Fisher Lane, Rockville, MD 20857. Publication Number 99109.5GasTech Inc. or equivalent.6OVA-108 or 128, Foxboro, or equivalent.7MIRAN 101, Foxboro, or equivalent.D 4276 02 (2007)3