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Procedia Engineering ProcediaProcedia Engineering 00 (2011) Engineering 26 000–000 (2011) 2065 – 2069 www.elsevier.com/locate/procedia
First International Sympos ium on Mine Safety Science and Engineering
Application of Lockout & Tagout System in the Coalmine Industry ZHANG Hong-jiea,b, LIU Zhen-tangc a* a b
College of Resources and Environmental Engineering, Wuhan University of Science and Technology,Wuhan 430081,China Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources Wuhan 430081,China c School of Safety Engineering, China University of Mining & Technology, Xuzhou 221008, China
Abstract In order to change the present of safety management, the safety issues are analysed in this article ,which are caused by the unexpected release of energy when producing and maintaining in coal mine industry. The importance of Lockout & Tagout (LOTO) system for safety management of coal mine industry was also expatiated. And then the process of LOTO System is introduced, the requirements and methods of LOTO System operated in coal mine are raised. It has important significance in reinforcing the safety management, enhancing safety production persistent effect mechanism construction and realizing safety production in coal mine.
© 2011 Published by Elsevier Ltd. Open access under CC BY-NC-ND license. Select ion and/or peer-review under responsibility of China Academy of Safety Science and Technology, China Un iversity of M ining and Technology(Beijing), McGill University and University of Wollongong. Keywords: Lockout & Tagout (LOTO); safety production in coal mine industry; zero-injury
1. Introduction Lockout & Tagout (LOTO) [1-4] is a method of keep ing equipment fro m being set in motion and endangering workers. On September 1st, 1989, OSHA issued a final ru le on the Control of Hazardous Energy (Lockout & Tagout) in Vo lu me 29 of the Code of Federal Regulat ions (29 CFR), Sect ion 1910.147. This standard, which went into effect on January 2, 1990, helps safeguard employees fro m hazardous energy while they are performing servicing or maintenancing on machines and equipments by
* Corresponding author. Tel.: +86-158-027-98067; fax: +86-027-688-62876. E-mail address:
[email protected].
1877-7058 © 2011 Published by Elsevier Ltd. Open access under CC BY-NC-ND license. doi:10.1016/j.proeng.2011.11.2406
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identifying the practices and procedures necessary to shutdown and lockout or tagout machines and equipments. Coal mine production belongs to high dangerous industry, and has power, ventilation, drainage, pressure gas, lift ing and transport systems which have great energy and are driven by air pressure, hydraumatic and electricity. And the injury, death and loss may happen when the energy is released unexpectedly because of wrong operation. So, in coal mine industry, it is necessary to have LOTO system to reinforce the control of maintain process, prevent the energy from unexpected release . The aim of LOTO system is to instruct the coal mine co mpany to establish management model for maintain ing or servicing, prevent accident , keep the safety situation stable, and get zero-injury goal finally. 2. LOTO system 2.1. Definition and scope of LOTO LOTO refers to specific pract ices and procedures to safeguard employees fro m unexpected startup of mach inery and equip ment, or the release of hazardous energy during setup, service or maintenance activities. To lock out equip ment, a lock is placed on the energy source, control, or isolating device. The LOTO system applies to the maintenance and commissioning in industry, such as the maintenance for power distribution system, maintenance for equip ment. It can be used in d ifferent kinds of industry, such as manufacture, chemical and coal mine. 2.2. LOTO equipment Types of isolation devices include Personal locks (red), Equip ment locks, Group locks (Green), Identificat ion Tags, Multi-lock Devices, Isolators, Group Isolation Board and Locking devices. Personal locks protect people when they are working on isolated equipment. Equip ment locks are used to secure isolators in the safe (isolation) position, to prevent the accidental or inadvertent movement of the isolator. Group locks are used by Isolation Coordinators and attached to Group Isolation Boards to lock the board in the active position and to secure all Equip ment Lock keys used in a Group Isolation into the lockable compart ment of the board. Identificat ion tags are purple and white in co lour and are used to identify unlabelled locks. Multi-locks is a device that is used to attach more than one lock to an isolator, when a mu lti-lock is used an equipment lock attached. Isolator is a device which positively separates or blocks the energy sources to equipment, the device is not capable of remote operation whist in the isolation position. Group Isolation Board is used exclusively for Group Isolation and considered identical to an isolator when used with these regulations. Locking device is a pro minent warning device, such as a tag and a means of attachment, wh ich can be securely fastened to an energy isolating device in accordance with an established procedure, to indicate that the energy isolating device and the equipment controlled may not be operated until the tagout device is removed. 2.3. Control process 2.3.1 Define when a lockout needs to occur
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It’s important that there is a clear distinction between normal production operations and instances when a lockout is needed. 2.3.2 Identify all potential energy sources A simp le d isconnect of the main power switche is not sufficient, as other types of energy may exist, such as hydraulic, electric, thermal, rad ioactive, pneumatic, gravity, and chemical energy. It’s also important to drain, release, or b lock any stored energy. 2.3.3 Procedure preparation The procedure documents the individual items of equipment to be isolated. The isolation planner should inspect the work site to determine which plant and equipment requires isolation and the boundary of isolation and hazards. 2.3.4 Train emp loyees To provide technical train ing to employees who are authorized to apply locks and tags to equipment and awareness training to those who are affected by the equip ment such as machine operators, workers in close proximity, and management contacts. 2.3.5 Isolation steps Inform all mach ine operators of the lockout. Locate energy isolating devices correctly. Attach locks along with a warning tag indicating the date, purpose, length of the lockout and who installed the lock. Use uniquely key locks that come with only one key to ensure that employees cannot remove each others’ locks. After the lockout procedures having been performed, test the operation of the machinery to ensure that all energy sources have been secured. Fin ish the work. Remove the indiv idual lock. Remove all other lock-out equipments. Inform all operators that the LOTO has been finished. Figure 1 shows the control processes of LOTO. Define when a lockout needs to occur
Identify all potential energy sources
Procedure preparation
Finish
Isolation Implementation
Train employ ees
Fig. 1. Control process of LOTO
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3. The safety issues caused by equi pment mai ntaining in coal mine industry Equip ment safety is very important for the production in coal mine industry. Meanwhile, the maintaining management is difficult because of the complex production environment in coal mine.So, it is a hard task to reinforce the management of equip ment maintaining and prevent accidents. The reasons of accident: 3.1. Safety budget is not enough, the technology of equipment is bad The technology of equipment in whole coal mine industry is bad because of the defect of technology level, technics design, raw material, the manufacture and test method, and the defect of capability of related industry, such as material, electron, hydraulic pressure and mechanism fittings [5]. Now, most of coal mines are transforming fro m mechanism to robotizat ion, but many equipments were damaged because of wrong operation. 3.2. Professional is lacking, the employee is not competent People plays an important ro le in production, and unsafe behavior of people is one of the main reasons of accidents. According to the accident statistics, 80% of accidents are caused by the unsafe behavior of people. 60%-70% of whole emp loyees are temporary in coal mine industry [6-7]. And the mechanism and electricity professional are lack in 96% of coal mine companies. So, many maintain emp loyees are not competent. Meanwhile, the work environ ment is bad and the geology is complex in coal mine, so, the accident is easy to happen when the workers are maintain ing equipment in such situation. 3.3. Defect o f management procedure for equipments There are not practical operation safety standards, the management procedures are defect ive, and the critical is not clear, these factors make the equip ments management harder [8]. Meanwh ile, some monitors are not responsible, the coordination is not enough, and the co mmunication among managers, operators, isolators and electricity engineer is not enough, so, it makes the maintain accidents are easy to happen. 4. Application of LOTO system in the coal mine industry Shock Accident in coal mine(Accident description): June 15, 1981, in a coal mine, a electrician was going to replace the transformer for the transferring pipe , He opened the switch and tested, and he confirmed that the transformer was not electriferous. So, he began to work on it, one coal mine worker found that the power wasn’t supplied on site, so he went to the power distribution station and turn on the power switch, the electrician was shocked and dead. It is a typical accident caused by the unexpected release of power, so, we can use the LOTO system to control the maintain process, following are the steps: Prepare a LOTO procedure, the procedure includes: • The switch in power distribution station must be isolated. • Isolation equipment is provided. • The electrician is responsible to isolate the switch in power d istribution station. Train ing: the electrician should be trained according to the procedure. LOTO steps:
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• • • • • • • • • • •
Inform the related person that a LOTO will be going Turn off the switch in the power distribution station Isolate the switch with a isolation equipment Lock the isolator with equip ment lock and individual lock Attach a tag along with lock Test the transformer wh ich needs to be replace to check that the transformer is not electriferous Replace the transformer Remove the indiv idual lock Remove the equipment lock and tag Turn on the switch Inform all the related people that the LOTO is fin ished As the below process shows, no one can turn on the switch in the power distribution station because the switch is locked, it can ensure that the worker is safe when he is working on the transformer.
5. Conclusion In this paper, a feasible approach is provided to how a zero-in jury culture in the coal mine industry can be cultivated by adopting LOTO system. Firstly, the definition, scope and control process of LOTO system were expat iated, the main problems existing in the process of mechanical and electrical equip ment repairing in coal mine were analyzed. Secondly, an examp le was provided to indicate that how to apply LOTO system in the coalmine industry. It is clearly that standardized and effective operation of LOTO system will reinforce occupational safety management, enhance the establishment of persistent effect safety management mechanism. References [1] Behnam Emami-Mehrgani, SylvieNadeau,Jean-Pierre Kenne´. Lockout/tagout and operational risks in the production control of manufacturing systems with passive redundancy [J]. Int. J. Production Economics 2011;132:165-173. [2] Ebeling, C.E.. An Introduction to Reliability and Maintainability Engineering. New York: McGraw-Hill Companies; 1997,p. 308. [3] Gershwin, S.B.. Manufacturing Systems Engineering. Prentice-Hall, Engle- wood Cliffs, New Jersey 2002, p. 267. [4] Gwo-Liang, L., Yen Hung, C. and Shey-Huei, S.. Optimal economic production quantity policy for imperfect process with imperfect repair and maintenance. European Journal of Operational Research, 2009;195, 348–357.(In Chinese) [5] ZHAO Hong-li. The analyse and preventive measure for mechanism and electricity accident. Coal China, 2010;36:34-35+40. (In Chinese) [6] YU Jia. The analyse and preventive measure for mechanism and electrician accident. Coal China, 2004;30:53-54. (In Chinese) [7] LU Jian-bao. Reason analyse and control measure for accidents caused by mechanism and electricity transportation. Safety in Coal Mines, 2003;34:39-40. (In Chinese) [8] CHEN Yong-can. Safety management measures of electromechanical equipment for coal mine. Colliery Mechanical & Electrical Technology,2002;5:44-45. (In Chinese)
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