Electrical safety systems in engineering industry using what-if analysis.
The failure in electrical system may result in physical damage to property and mainly cause in high risk of electrocution. Regarding electrical safety there have been many solutions and guide to mitigate and reduce the electrical accident. Already Alex albert says in 2013 Safety risk management for electrical transmission and distribution line construction. An electrical power lines has been the largest cause of electrical fatalities in both domestic and in industries and also in engineering industries. In majority construction side because in this field contractors in maintenance of electrical transmission and distribution are in extremely high risk of electrocution. This would help to reduce the electrical bun injury, unexpected injury . The electrocutions occur due to below factor: age, gender, duration of voltage passing in our body, amount of voltage, passage through the body. These factors describe the type of injury that occurred due to electrocution.
Types of electrical protection systems:
1. Over load protection
2. Over voltage protection
3. Type of voltage AC/DC
4. Short circuit protection
5. Earth fault protection
6. No load protection
7. Protection against surges and voltage fluctuation
8. Interlock protection system
As already discussed Alex albert say's that electrical contractors involved in the construction and in electrical maintenance lines are at high risk. Finally he suggested that further conducting of research must be help to reduce risk between different activities and prevention method.
In 2013 Manuel Suarez-Cebador accord to him the severity of work place electrical accidents occurs on construction sector. This research enables the safety experts, government officials industries to identify priorities and to design strategies to minimize the electrical accidents in construction and engineering sector.
In 2004 Colominassays that safe grounding system which results in carry and dissipate the electrical current to ground. When fault conditions and to safeguard of people working with machineries which manages equivalent current to the system.
Major Problems in Engineering Industry:
1. In heavy engineering industry the electrical equipment shows accidents like electrical shock, electrical burn, fire & explosion, hazards due to electric welding and cutting.
2. It happens mainly due to overloading, and improper handling of cords, improper loading of electrical equipment's.
3. Worker on direct contact with energized equipment, and improper insulation for damaged cords and also due to improper usage of tools.
4. And finally lack of personal protective equipment's like resistant helmet, rubber gloves, googles, apron etc.,
Definition of What-if Analysis:
It is a brain storming approach that uses road, loosely structured questioning to postulate potential upsets that uses that may result in accident or system performance and to ensure appropriate safeguards against those problems are provided.
[FIGURE 1 OMITTED]
1. Preparing for review
2. Performing the review
3. Documenting the result
Table 2: Work sheet format for what if What if Consequences/ hazards Safeguard & Recommendation
In the 1st column what if type of questions are to be asked.
In 2nd column describes the consequences and hazards arise.
In 3rd column implemented safety systems and additional suggestion to improve.
Result discussion with safe guard & reccomendations What if analysis:
The following is the chart prepared for the purpose the assessment of electrical safety system in the industry
Table 3: Chart for "what- if" analysis related to Electrical Safety. What if Consequences/ Safeguard & hazards recommendation What if inspection The current leakage periodic maintenance and maintenance is is not pass on to is to be done not done in earth the earth pit(as per IS 3043--1987: Code of practice for Earthling) What if the glands Person in contact All glands are need of the motors and with glands will get to be dual earthed control panels in shock not dual earthed? (as per IS 3043--1987: Code of practice for Earthling) What if the doors The fault current All doors and fence and fence of the may pass to the need to be earthed transformer and attendees control panel area is not earthed? What if the static Static energy may Static energy discharge point for pass between flowing discharge point need men at work is not medium and men at to be provided at provided near liquid work all liquid transfer transfer area? areas. What if the display The fault current Analyzing the earth fails in relays and may damage the nature at that point circuit breakers? system when the and go for chemical earth is too earthling? resistive What if excavation Electrical discharge Before excavation, is carried out over on the excavator live conductors to the underground be isolated and earthling electrodes earthling points to and the buried live be unearthed-the conductors? underground earthing and live lines to be clearly marked over the ground. What if the fire Fire hazard Provide suitable occurs in the main fire extinguishers- substation, Toshiba has one in transformer yard and 15mtrs any of electrical panels?(Asper IS 2190 -Selection, installation and maintenance of First-Aid Fire Extinguishers) What if the gas in The gas leaks to the Proper refilling the gas circuit atmosphere and device (eg: Dilo- breaker (GIS-Gas deplete the ozone germany) has to be Insulated Switch (SF6-sulphur used(in Toshiba the gear)is leaked and hexafluoride-is a approximate leakage what if the gas ozone depleting will be 0.1% in a refilling is not substance(ODS)) month) under proper system? What if the Electric hazard Choose Suitable electrical supply rating lines of an apparatus is not provided with sufficient rating of either insulation or current carrying capacity or voltage or mechanical strength? What if the danger Persons may get in Danger notice to be notice is not contact with placed at provided in the electric shock appropriate places appropriate places? (As per The Indian Electricity Rules, 1956-Chapter Iv- General Safety Requirements-Rule 35. Danger Notices)? What if the portable Lead to Electrical Proper pre tools are not hazards inspection and provided with the handling of the heavily insulated portable tools as and adequately per IS rules to be protected setup? maintained, and (The Indian pneumatic portable electricity Rules, tools is recommended 1956-Chapter X for critical Additional operations precautions to beAdopted in mines and oil-fields, Rule-124. Portable and transportable machines)? What if the Electric Shock Suitable protective protective devices tools have to be fail during the employed and before operation? using it has to be checked for eligibility at the time of issuing work permit. What if the Leads to mishaps Standard color is different lines and used to circuits are distinguished the notdistinguished? different lines and circuits What if the auto Diesel generator Frequent checking main panel (AMF) will not startup has to be fails? leads to various established issues related to failure in uninterrupted power supply What if the roof Electric and fall All roof trusses trusses are not hazard with purlins has to earthed? be earthed What if the ELCB is The faulty situation Suitable rated ELCB employed or not is not identified has to be provided working? and to inspect periodically. What if the L.P.G Chance of fire is To be avoided and lines are present more isolated near powerhouses? What if the alerting Leads to hazards LOTO has to be techniques like LOTO employed is not followed? mandatorily. What if the Gloves fail to act Periodical changing electrically as an insulator of rubber gloves to protected rubber be followed gloves are not changed periodically? What if the flame Leads to fire or Flame and dust proof and dust proof light failure of equipment equipment has to be fittings is not used employed at in required areas? appropriate places. What if the Major mishap Periodical bus bar interlocks in cleaning has to be the bus bar fail? done
Check list Analysis:
The following is the chart prepared for the purpose the assessment of electrical safety system in the industry.
Table 4: Checklist for electrical safety analysis ITEMS YES NO GENERAL * Safety signs and tags used when necessary to warn YES employees about electrical hazards. * Electrical sirens are used for specified places YES where much attention is needed * Barricades used with safety signs when necessary to YES prevent or prohibit the employee access to work areas. * Signalman need to warn when signs or barricades are YES not sufficient to prevent unauthorized access. * Is electrical safety part of your staff induction? YES * Do all electrical equipment and cords have NO inspection tags? * Light switches easily locatable and in good YES working order? * Is emergency lighting and exit lights adequate for YES the area? * Is their ELCB is installed in circuits to facilitate YES at regular intervals? * Are power switches and sockets are in good YES condition and labeled? * Area is free from unexpected tripping of circuit YES breakers? * Plugs are properly inserted all of the way into YES the power sockets? * Appropriate use of power boards or extension leads? YES * Are extension cords a suitable length? YES * Immediate removal of any frayed or damaged NO electrical leads. * Are flexible cords effectively anchored to YES equipment, plugs and sockets? * Air vents and cooling fans in electrical equipment YES are free from blockage? Fans are quiet? * Is faulty electrical equipment clearly marked and YES removed from service? * Combustible material is not stored near electrical YES equipment? * Do you report faulty electrical installations YES immediately? * Work area free of any trip hazard from leads YES and cables? * The fire protection system is employed on YES essential places * The employed fire protection system has sufficient YES strength to handle the fire load at that point (As per IS 2190 -Fire Extinguishers) * While permitting a hand tool inside work area the YES fitness passport has to be issued * All ELCB's to be not more than 30milli amps YES * Necessary checklists (e.g.: maintenance, YES housekeeping, checking of an apparatus etc.) are maintained * Workers must certified for their skills where ever NO required to perform and verified for their validity of license(e.g.: worker certification grades like B&C grades) * Illumination on shop floor is as per IEC rule(Asper YES The Indian Electricity Rules, 1956- Chapter X- Additional precautions to be Adopted in mines and oil-fields 113. Lighting, communications and fire precautions)? * Operational and working distance has been NO maintained (e.g.:panels and transformers)? * Non sparking tools(e.g.:brass) are used in the YES LPG area * Lightning arrestor are managed with suitable YES coverage? (Asper TheIndian Electricity Rules, 1956. Chapter VIII-Overhead Lines, Under Ground Cables And Generating Stations, Rule 92. Qualified persons trained in and familiar with: * Technically skilled person necessary to distinguish YES to manage the live parts from other parts of electric equipment. * Voltage determination. YES * Clearance distances that must be maintained. NO * For specific hazards training has conducted has been NO specific to which the employee may be exposed to risk during working. Procedure provided for work on or near de-energized parts: * Written procedures specific to the equipment YES or worksite. * De-energizing equipment. YES * Application of locks and tags. YES Working on or near exposed energized parts: * All employees who work near to a hazard have been YES trained, and are aware of the practices. * Only qualified employees work on energized parts. YES * Is an Overhead line are de-energized and grounded YES prior to working near them or other protective measures used. * Vehicle and mechanical operators understand that YES they must maintain a safe working distance. * Insulating barriers are used and installed YES as required. * Insulating mat is provided at all electrical YES equipment area * Illumination is provided at all worksites to YES assure safe work. * Protective shields and barriers provided to protect YES from the energized parts in confined space * All conductive materials such as pipes, rods, etc. YES covered or insulated. * Housekeeping performed when energized parts may YES not in contacted. * Only qualified persons allowed defeating electrical YES lockout & tag out system must be followed work on equipment. Portable electric equipment such as cord-and-plugs, including flexible cords: * To avoid damage of cords avoid horse play with cords. YES * Not used to raise or lower equipment. YES * Not fastened with staples or hung so as to damage YES insulation. * Visually inspected before each use on each shift. YES * Defective items removed from service. YES * Plugs and receptacles mate properly. YES * Flexible grounding-type cords have a grounding YES conductor. * Grounding plug not defeated. YES * Adapters which interrupt grounding continuity not YES used. * Approved equipment used for work during working NO under conductive locations (e.g. wet locations, etc.). * Is portable cable reels unwound fully before use? YES * Look at joints are properly secured after YES the connections Test instruments and equipment: * Used by qualified persons only. YES * Visually inspected before use. YES * Test instrument to be rated for the circuit which is YES to be tested and appropriate for the environment. * Cabling of Electrical equipment ignite flammable or YES ignitable materials not used if present in the worksite. Safeguards For Personnel Protection: * Protective equipment is used when there is exposure YES to potential electrical hazards. * Are safety glasses or goggles used to protect eyes YES or where there is a sparks, danger of arcs, flashes or flying objects? * Approved gloves worn that are appropriate for YES the hazard present * Are Insulated tools or handling equipment used while YES working in conductors? * Is Insulated fuse, ELCB, handling equipment are YES used to remove or install fuses when terminals are energized? * Is non-conductive ropes and hand lines used near NO energized parts and are protected from moisture. * Is Protective shields, barriers or insulating YES materials are used to protect employees during working near exposed energized parts.
From the above analysis and reports it has been ranked low, medium, high the importance and attention needed to be taken.
** Roof trusses are not earthed
** Open wires and bare cables is present at few places
** Electrically protected rubber gloves are not changed periodically.
** All transformer doors and fence earthing is missing at few places.
** Static discharge points are not provided near L.P.G yard and transformer yards.
** Ropes used near energized parts are conductive and are not protected from moisture.
** Workers under contractors are not ensured for their electrical operation certification.
** L.P.G lines are near 11KV/440V substation.
The concept which lies behind the selection of this current project is the Principle of Dominos philosophy. Unsafe actions and unsafe working conditions will pave the way for the injury and will even lead to the accidents. From the assessment of electrical safety practices with the application of the checklist analysis and what if analysis in the heavy engineering industry, the individual activities/ operations/ equipment's/ practices are going be assessed for the finding of the electrical hazards.
Initially the list of practices and points are logically and virtually analyzed and a chart is prepared necessary for the data collection to comply with the checklist and what if analysis. In future, the project will end with the findings of hazards, suggesting the recommendations and control measures of safe work practices associated with the electrical activities.
[1.] Alex Albert, Matthew R. Hallowell, 2013. published a paper on the "Safety risk management for electrical transmission and distribution line construction"
[2.] Manuel Suarez-Cebador, Juan Carlos Rubio-Romero, Antonio Lopez-Arquillos, 2013. published a paper on the "Severity of electrical accidents in the construction industry in Spain"
[3.] Price, C.J., N.A. Snooke, S.D. Lewis, 2006. published a paper on the "A layered approach to automated electrical safety analysis in automotive environments".
[4.] Gheorghe Grigoras, Cecilia Barbulescu, 2013. published a paper on the "Human errors monitoring in electrical transmission networks based on a partitioning algorithm"
[5.] James, C., Cawley, Gerald T. Homce, 2003. published a paper on the paper" Occupational electrical injuries in the United States, 1992-1998,and recommendations for safety research"
[6.] Xinyan Huang, Yuji Nakamura, Forman A. Williams, 2013. published a paper on the paper" Ignition-to-spread transition of externally heated electrical wire".
(1) Ranganathan. K, (2) N. Nagarajan, (3) K. Mugundhan, (4) PSS. Srinivasan, (5) K. Visagavel, (6) D. Sakthivel
(1) Student, Department of Industrial Safety Engineering, Knowledge institute of technology, TamilNadu, India.
(2,3,4,5,6) Faculty of Mechanical Engineering, Knowledge Institute of Technology, Salem, Tamilnadu, India.
Received 25 April 2016; Accepted 28 May 2016; Available 5 June 2016
Address For Correspondence:
Ranganathan. K, 1Student, Department of Industrial Safety Engineering, Knowledge institute of technology, TamilNadu, India.
Table 1: Effects of electrical current in the human body Current Reaction Below 1milli ampere Generally not observable 1milli ampere Faint tingle 5milli ampere Felt disturbing like shock, but no pain. 6-25milli ampere (women) Muscle control loss and painful shock occurs 9-30milli ampere The freezing current lead to muscle disturbing it causes to injury 50-150milli ampere Extreme pain, respiratory arrest, serves muscle reactions. Death is possible. 1000-4300milli ampere Heart ceases from pumping action. Occurrence of nerve damage and muscular contraction. 10amperes Probably death, Cardiac arrest, severe burns.
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|Author:||Ranganathan, K.; Nagarajan, N.; Mugundhan, K.; Srinivasan, PSS; Visagavel, K.; Sakthivel, D.|
|Publication:||Advances in Natural and Applied Sciences|
|Date:||Jun 15, 2016|
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