Electricidad - 651 entradas encontradas
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Hess H., Liere H.
Safety in electrostatic powder coating
Sicherheit beim EPS-Verfahren [en alemán]
The types of powder used are generally flammable when mixed with air in certain concentrations, and these always occur in the neighbourhood of the spray guns and powder recovery equipment. Ignition can be produced by electrostatic discharges with an energy of at least 5mWs. Conditions leading to spark production between the gun and the workpiece in the booth are examined. Primary safety measures against hazardous accumulation of electrostatic charges on the workpiece are described: control of the insulation resistance of the workpiece (maximum 1 megaohm) before it enters the booth; electrostatic earthing, interlocked with the equipment. Secondary measures: automatic fire detectors interlocked with the booth equipment; automatic extinguishing system; flame arrester in the pipework between the recovery equipment and the spray booth; shut-off valve actuated by the explosion shock wave; explosion vents in the recovery plant; explosion suppression by extinguishers. Recommendations are made for cleaning the booth.
Industrie-Lackier-Betrieb, 1977, No.4, p.133-136. Illus.
Puncture voltage - leakage current?
Durchschlagspannung - Ableitstrom? [en alemán]
Description of tests on the insulating power of work clothes and the use of newspaper for insulating the place of the rescuer in the presence of potentials below 1kV. Knowledge of the insulating power of clothes is of value for calculations in inquiries into accidents and especially when clothing is used to rescue the victim of an electrical accident. The puncture voltage was found to be between 320 and 2,760V according to the thickness and type of the fabric. The intensity of the leakage current was 19-92µA. These values were measured with dry fabric: damp or wet clothing provides no electrical protection. Tests on the insulating power of newspaper confirm that standing on a thick newspaper can have a protective effect for the rescuer.
Sicherheitsingenieur, Oct. 1977, Vol.8, No.10, p.10-16. Illus.
Schrimmer P., Mertens D.
Accumulation of static electricity on flat belts and conveyor belts
Elektrostatische Aufladung von Flachriemen und Förderbändern [en alemán]
Report on tests and measurements of static electricity charges accumulated on plastic transmission and conveyor belts: method used for measuring the electric field, test equipment and test conditions, test methods and results. The authors show the influence of peripheral speed, tension exerted by the shafts and local atmospheric humidity on the electric field, and draw the conclusion that the long-term static electrical charge should not give rise to apprehension, as the intensity of the electric field remains constant, and even diminishes, when the machinery is kept running for a long time. They stress the fact, however, that the belts tested were manufactured by the same firm, and that tests on other belts might give quite different results.
Maschinenmarkt, 1977, No.11, p.166-169. Illus. 3 ref.
Construction of overhead telecommunication lines
Construction de lignes aériennes de télécommunication. [en francés]
Construction of telecommunication lines can give rise to accidents due to tipping over or breakage of wooden poles already in place, or electric shock either through contact with a neighbouring electric power line during lifting of poles or by direct contact with electric conductors on poles used for both installations. These situations and general precautions (especially administrative) are examined in the light of the relevant French directives or regulations. The practical measures to be taken at the different stages of the work are set out (mechanical drilling; raising, driving or removing poles; unwinding of lines; removal of wires and cables) and an extract from the relevant instructions issued by the Telecommunications Directorate for its officers.
Cahiers des Comités de prévention du bâtiment et des travaux publics, Nov.-Dec. 1977, No.6, p.297-305. Illus. 5 ref.
Krivova T.I., Lukovkin V.V., Morozov Ju.A., Sazonova T.E., Asanova T.P., Revnova N.V.
Influence on the human body of the electric field caused by high voltage AC current electrical equipment
Vlijanie ėlektričeskogo polja, sozdavaemogo ėlektroustanovkami vysokogo naprjaženija peremennogo toka, na organizm čeloveka [en ruso]
As a result of complaints made by workers employed in substations or near very high voltage overhead lines (220 to 750kV), the authors measured the intensity of the electric field at various workplaces and carried out medical examinations on 385 workers exposed at these workplaces. The complaints covered objective symptoms (functional disorders of the central nervous system, autonomic dysfunction, nervous asthenia). Haematological tests revealed erythrocyte and leucocyte changes. Several volunteers from the exposed workers, and a number of controls, underwent ergometric and perceptual-motor performance tests. The results showed that there is a relation between duration of exposure and the severity of autonomic disorders. This research was used as a basis for setting standards limiting the duration of exposure to electric fields.
Naučnye raboty institutov ohrany truda VCSPS, 1977, No.108, p.33-39. 15 ref.
Ministry of Labour (Ministčre du travail), Paris.
Order of 22 June 1977, to permit certain exceptions to ss. 32, 35 and 36 of the Decree of 14 Nov. 1962, which prescribes AC voltage limits
Arręté du 22 juin 1977 portant dérogation aux dispositions des articles 32, 35 et 36 du décret du 14 novembre 1962 fixant les valeurs de tension limites en courant alternatif. [en francés]
The French Decree of 14 Nov. 1962 (CIS 63-228) prescribed the voltage limits for switchgear designed so as to avoid the dangerous potential of the equipment frame (to earth, or to a nearby frame) exceeding 24V (AC) if the frame is situated in a highly conductive enclosure or work site, or exceeding 50V (AC) in other cases. This Order allows for exceptions to this rule over a period of 3 years. A Technical Note (SEC/EL No.3) of 11 Aug.1977 issued by the Ministry of Labour, commenting on this Order, was published in Cahiers de notes documentaires - Sécurité et hygične du travail, Paris, France, 1st quarter 1978, No.90, Note No.1105-90-78, p.157-158.
Journal officiel de la République française, 11-12 July 1977, No.81 (Supplementary issue), p.4005.
Ministry of Labour (Ministčre du travail), Paris.
Order of 20 June 1977, providing for an exception to s.8, para.3 of the Decree of 14 Nov. 1962, which prescribes the use of very low voltage current for portable apparatus and equipment in highly conductive enclosures
Arręté du 20 juin 1977 portant dérogation aux dispositions du paragraphe 3 de l'article 8 du décret du 14 novembre 1962 relatives ŕ l'usage de la trčs basse tension pour l'alimentation des appareils et engins portatifs ŕ main ŕ l'intérieur des enceintes trčs conductrices. [en francés]
Section 8 of the French Decree of 14 Nov. 1962 (CIS 63-228), makes it compulsory to use very low voltage current supply for portable apparatus and equipment in highly conductive enclosures. This Order permits of one exception to this rule, in certain conditions. A Technical Note (SEC/EL No.4) of 20 Aug. 1977 issued by the Ministry of Labour, commenting on this Order, was published in Cahiers de notes documentaires - Sécurité et hygične du travail, Paris, France, 1st quarter 1978, No.90, Note No.1106-90-78, p.159.
Journal officiel de la République française, 11-12 July 1977, No.81 (Supplementary issue), p.4005.
Stoljarov M.D., Moiseev A.G.
Portable screen for protection against electric fields - Protective screen against the effects of electric fields for workers on pylons
Perenosnoe ėkranirujuščee ustrojstvo dlja zaščity ot vlijanija ėlektričeskogo polja - Ėkran dlja zaščity personala ot vozdejstvija ėlektričeskogo polja pri rabotah na vysote [en ruso]
Description of 2 types of screen for electricity workers working in the immediate vicinity of very high voltage current (400, 500 and 750kV) distribution installations.
Ėnergetik, July 1977, No.7, p.15-18. Illus.
Permits-to-work on medium-voltage distribution installations
L'AIST sur les ouvrages MT ŕ la distribution. [en francés]
Practical information on the permit-to-work (AIST) and its use in medium-voltage distribution installations: person issuing it (manager of the installation where the work is to be carried out); details it must contain (clear, accurate and complete definition of the work); issuing procedure.
Vigilance, June 1977, No.56, p.14-22. Illus.
Sheppard A.R., Eisenbud M.
Biological effects of electric and magnetic fields of extremely low frequency.
This study is a critical review of the literature on the effects of electric and magnetic fields of 0-300Hz. The basic biophysical principles are discussed, exposures to man-made electromagnetic frequency fields are summarised, and the biological effects of exposure are treated under the main heads: haematological and biochemical effects; physiological and behavioural effects in humans and lower animals. A number of special topics are dealt with. In the course of the review, more than 100 papers are specifically studied.
New York University Press, Washington Square, New York 10003, USA, 1977. 270p. 410 ref. Price: US-$15.00.
Issel I., Kempe H., Seeber A., Wolf I.
Fitness examinations for linemen
Tauglichkeits- und Eignungsuntersuchungen an Elektromonteuren [en alemán]
Results of 215 initial and 65 follow-up examinations indicate the importance of evaluating the locomotor apparatus and sense organs. Psychodiagnostic tests are required only when the physician notes anomalies in behaviour or in personality or job development. The main activities, work requirements and medical examination methods are listed.
Das deutsche Gesundheitswesen, 1977, Vol.32, No.32, p.1526-1531.
Mauthe G., Krieter H.G.
Earthing switches in metal-clad high-voltage SF6 switchgear installations.
Les sectionneurs de mise ŕ la terre dans les postes blindés ŕ haute tension isolés au SF6. [en francés]
During assembly and maintenance work on electrical installations, the safety of personnel requires switchgear installations to be provided with earthing facilities at appropriate locations. In metal-clad, high-voltage installations (complex enclosed units insulated by means of sulfur hexafluoride (SF6)), earthing rods cannot be used at arbitrary points on the conductor, so that earthing switches must be permanently installed. After an enumeration of the criteria for earthing switches, a range of earthing switches for this type of switchgear is presented, and it is shown that the required conditions are satisfied.
Brown Boveri Review, Nov. 1977, Vol.64, No.11, p.662-666. Illus. 6 ref.
Ščuckij V.I., Petrov Ju.S., Korotkov I.M.
Establishment of minimum values for insulation resistance in electric shotfiring circuits with blasting caps connected in series
Obosnovanie dopustimyh norm na soprotivlenie izoljacii ėlektrovzryvnyh cepej pri posledovatel'nom soedinenii ėlektrodetonatorov [en ruso]
Results of research on the influence of insulation resistance on the parameters of the circuit and on the initiating mechanism; development of criteria for establishing these minimum values. It is recommended that a resistance of at least 5,000 ohms should be used if the circuit has less than 300 blasting caps in series. If there are more than 300 caps, the insulation resistance should be more than 5 times the calculated rated resistance of the shotfiring circuit. Observation of these minimum values would contribute to prevent accidental triggering of the circuit.
Gornyj žurnal, May 1977, No.5, p.60-63. Illus. 4 ref.
Cook W.I., Fletcher W.G.
A report on the performance of linemen's rubber insulating gloves
This report presents the results of a study of the extent of compliance of 12 models (chosen randomly from 155 available models) of gloves with the American National Standards Institute J6.6 standard. AC voltage, thickness, design and dimensions, tensile strength, elongation, insulation resistance, and tension set were tested. In general, the gloves were in compliance.
DHEW (NIOSH) Publication No.77-196, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, Ohio 45226, USA, July 1977. 18p. 5 ref.
Light W.G., Wei E.T.
Surface charge and asbestos toxicity.
The relations between surface charge and haemolytic activity (ability to rupture the erythrocyte membrane) of asbestos are studied in investigations with chrysotile and amphibole asbestos. The haemolytic activity of the chrysotile, which has a positive charge, was initially higher than that of the negatively charged amphibole. Leaching caused the magnitude of the surface charges to converge, so that the haemolytic activity of the chrysotile diminished and that of the amphibole increased. This could explain why the 2 classes differ more in their short-term in vitro effects than in long-term toxicity.
Nature, Feb. 1977, Vol.265, No.5594, p.537-539. Illus. 25 ref.
National electrical safety code.
This edition supersedes all former editions of the National Electrical Code and was adopted as American National Standard ANSI C2 on 28 Feb. 1977. It covers in 4 main parts basic provisions and work rules for the safeguarding of persons from hazards arising out of the installation, operation and maintenance of conductors and equipment in electrical supply stations as well as overhead and underground electrical supply and communication lines. It is applicable to systems and equipment operated by utilities or by industrial establishments under the control of qualified persons. An extensive subject index is provided.
Institute of Electrical and Electronics Engineers, 345 East 47th Street, New York, N.Y. 10017, USA, 1977. 348p. Illus. Price: US-$6.50.
Guidance Note GS6, Health and Safety Executive, London.
Avoidance of danger from overhead electric lines.
The dangers of work where there may be contact with overhead lines and the legal obligations of those responsible for such work are outlined. The precautions to be taken at construction sites where there is or is not work or passage of plant under the lines are set out, with plans and drawings of the arrangement of barriers and access points.
H.M. Stationery Office, P.O. Box 569, London SE1 9NH, United Kingdom, Apr. 1977. 7p. Illus.
The effects of electric current on humans
Über die Wirkungen des elektrischen Stromes auf den Menschen [en alemán]
A historical review of the effects of electrical current in humans is followed by an outline of the present state of research on its cardiac effects. Classification of current strengths, and description of recent studies on resistance of the live human body. The practical implications of this new knowledge for electrical protection are discussed.
Elektrotechnik und Maschinenbau, Mar. 1977, Vol.94, No.3, p.107-118. Illus. 16 ref.
Lifting and construction site equipment used near overhead electric lines
Appareils de levage et engins de chantier travaillant au voisinage de lignes aériennes. [en francés]
This data sheet, prepared by a group of engineers of the French National Research and Safety Institute (INRS), recalls the French regulations concerning the operation of construction site equipment in the vicinity of overhead electric lines, and shows that merely earthing this type of equipment does not provide adequate protection for workers operating the equipment or slingers. The earthing circuit should be supplemented by an automatic circuit-breaker sensitive to fault current or fault voltage. Otherwise, construction site equipment not fitted with an automatic circuit-breaker of this kind should be kept well away from all electrical installations, as prescribed by regulations. Procedure to be followed in the case of accidental contact with overhead lines.
Cahiers de notes documentaires - Sécurité et hygične du travail, 1st quarter 1977, No.86, Note No.1047-86-77, p.41-46. Illus.
Eltschka R., Hofschneider H.
Operating behaviour of a fault-current circuit-breaker in three-phase current circuits with reference to direct current premagnetisation
Zum Betriebsverhalten eines Fehlerstromschutzschalters in Drehstromkreisen unter Berücksichtigung einer Gleichstromvormagnetisierung [en alemán]
This article deals with the special case in an electric circuit comprising a fault-current circuit-breaker where the alternating fault current may be complemented by a direct current component. Description of the operation mechanism and design of the fault-current circuit breaker and its behaviour in the event of direct-current premagnetisation. Studies of such circuit-breakers with different sensitivities are reported with oscillograms, and the conditions causing it to be triggered in the event of sudden introduction of direct current are presented.
Österreichische Zeitschrift für Elektrizitätswirtschaft, Sep. 1976, Vol.29, No.9, p.360-368. Illus. 5 ref.
Radiation shielding for high-frequency induction heating installations
Zaščita rabotajuščih na VČ-ustanovkah indukcionnogo nagreva [en ruso]
Description of the different types of aluminium sheet shielding for these installations, and inspection windows. Data on distances between shield and conductor, and thickness and material of shields are based on field intensity measurements on shields developed in the laboratory.
Gigiena truda i professional'nye zabolevanija, Nov. 1976, No.11, p.47-48. Illus.
Edwin K.W., Jákli G., Thielen H.
Evaluation of protective measures against dangerous electric currents
Möglichkeiten zur Bewertung von Schutzmassnahmen gegen gefährliche Körperströme [en alemán]
Important aspects of the hazards of electric currents (protective measures, types of network) are briefly reviewed. Assessment of protective measures by statistical correlation analysis of accident reports, and by reliability analysis of the measures themselves, is presented. The statistical approach comprises 3 stages: analysis of safety measures, analysis of accident reports, statistical evaluation of accident data. Statistics from Bavaria, Switzerland and the Netherlands, obtained with networks with combined or separate mid-point and neutral conductors, and with connection to neutral and earthing, are compared. The correlation procedure applied is suitable for assessment of measures employing a conductor for indirect-contact protection. Reliability analysis of protective measures employs the fault-tree method to determine the causes of undesirable system conditions and the probability of their occurrence. This method permits differentiated evaluation of the individual systems.
Forschungsbericht Nr.155, Bundesanstalt für Arbeitsschutz und Unfallforschung, Postfach 25, 4600 Dortmund 70, Germany (Fed.Rep.), 1976. 108p. Illus. 25 ref.
Protection against electrical hazards
Dai pericoli dell'elettricitŕ ci si difende cosě [en italiano]
A brief introduction on production and distribution of electricity is followed by a chapter on the physiological effects of the passage of electric current through the human body. Sections follow on the causes of electrical accidents and protection measures, especially contact voltage protection: earthing with overcurrent protective relay, earthing with automatic overvoltage relay circuit-breaker, earthing with differential current relay (low and high sensitivity), connection to neutral. Details of earth connections, insulating stools and safe distances. Table of relevant Italian standards. Chapters on the safety of electrical tools and first aid in the event of an electrical accident.
Rivista di meccanica, Oct. 1976, No.628, p.115-119, and Nov. 1976, No.630, p.101-110. Illus.
Safe work on electrical installations - Modern techniques and personal protective equipment
Sicherheit bei Arbeiten in und an elektrischen Anlagen - Neuzeitliche Hilfsmittel und persönliche Schutzeinrichtungen [en alemán]
After a review of the accident situation in the Fed. Rep. of Germany, the main safety rules and regulations are referred to and commercially available safety equipment for work on low and high voltage installations described: insulating covers designed to prevent reclosing the circuit; earthing and short-circuiting device with built-in voltage detector; guy-rope system for poles; connecting bars with built-in fuses; protective equipment for fuse replacement; fuse handles and insulated contacts; insulating blankets and covers; cable stripping devices; voltage detectors; protective clothing; insulated tools. Recommendations for work procedure and use of equipment. List of West German distributors.
de - der Elektromeister + Deutsches Elektrohandwerk, 1976, No.23, p.1513-1521. Illus.
Means of protecting personnel working in high-voltage substations against industrial frequency electric fields
Sredstva za zaštitu osoblja zaposlenog u visokonaponskim razvodnim postrojenjima od električnog polja industrijske učestanosti [en serbocroata]
Protection of high-voltage substation personnel against electric fields can be afforded by screens over passageways and workplaces, or by metallic scrim clothing. Calculations to optimise the effect of screening are reproduced with results. For screens placed 2.5m above passageways, parallel 3-5mm conductors at intervals of 20cm are recommended, while screens at the workplace should be made of a square-mesh grid (mesh size 5-10cm). Metallic scrim clothing should cover the whole body and present a specific surface resistance of 10,000 ohms.
Jugoslovenska i inostrana dokumentacija zaštite na radu, 1976, Vol.12, No.1, p.46-54. Illus. 3 ref.
Emergency treatment of electrical accidents
Die Notfallbehandlung beim Unfall durch elektrischen Strom [en alemán]
After an outline of the effects of electric current on man, especially on the skeletal muscles, nervous system and heart, and thermal effects, recommendations are made regarding identification of the lesion or disorders produced and especially regarding first-aid measures (resuscitation, prevention of shock). The final treatment of circulatory arrest devolves on the physician. This comprises above all use of defibrillation techniques or, in the event of cardiac arrest, of a cardiac pacemaker, plus administration of drugs. Advice for training of first-aid workers and preparation of the intervention in the event of an electrical accident.
Zentralblatt für Arbeitsmedizin, Arbeitsschutz und Prophylaxe, Sep. 1976, Vol.26, No.9, p.180-188. Illus. 21 ref.
Kravčenko V.S., Bondar' V.A.
Electric discharge and friction spark explosion safety
Vzryvobezopasnost' ėlektričeskih razrjadov i friktionnyh iskr [en ruso]
Summary: gaseous mixture ignition by capacitance and electrostatic discharges or by connection sparks (physical mechanisms, experimental determination of ignition energy, explosive limits, statistical and mathematical considerations, safety measures against electrostatic discharges, explosion-proof electrical circuits, etc.); gaseous mixture ignition by friction sparks (friction and wear theory, friction spark formation, ignition mechanism, examples of anti-sparking equipment constructed in the USSR; water spraying during pneumatic stowing and cutting in coal mines, plastic coated mine ventilators, non-sparking tools, etc.).
Izdatel'stvo "Nedra", Tret'jakovskij proezd 1/19, 103633 Moskva K-12, USSR, 1976. 304p. Illus. 267 ref. Price: Rbl.1.34.
Skorobogatova A.M., Tarasova G.M., Solevév A.V., Plotnikov V.G., Plotnikova L.B., Jakovleva M.N.
Influence of electrostatic fields on man and animals
O vlijanii statičeskogo ėlektričeskogo polja na organizm čeloveka i životnyh [en ruso]
An occupational health survey of several USSR textile mills showed that static electricity rose to 3,000-15,000V/cm. The frequency of hypertension and neurovegetative dysfunction cases observed among workers was 7.6% and 35.8%, respectively (1.4% and 5.7% in controls). Workers in high energy density electric fields exhibited formication sensation; the dielectric resistance of their skin showed large decreases. Experiments on rabbits in electrostatic fields showed increase in skin temperature, dilatation of capillaries and sympathetic nervous system disorders.
Gigiena i sanitarija, June 1976, No.6, p.20-24. 3 ref.
Nikolić M., Petrović M., Mijailović M.
Principles of protection against hazardous effects of electric current
Osnovi zaštite od opasnog dejstva električne struje [en serbocroata]
Contents of this training manual: risks of direct or indirect contact with live equipment and protection against these hazards; other hazards (short circuits, overload, overvoltage, static electricity, etc.); explosion prevention; consequences of hazardous effects of electric current on man; collective and personal protection (insulating gloves and shoes, insulated tools, etc.).
Institut za dokumentaciju zaštite na radu, Niš, Yugoslavia, 1976. 118p. Illus. 25 ref. Price: Din.90.
Nervous disorders due to electricity (a case of pontobular syndrome)
Accidents nerveux dus ŕ l'électricité (A propos d'un cas de syndrome bulbo-protubérantiel). [en francés]
MD thesis. The author recalls the physical factors underlying the effects of electric current on the human body and reviews the nervous manifestations of electric shock (clinical; nature of consequent nervous lesions). He then reports on apparently unique case of a lesion of the medulla oblongata and pons, with late symptoms culminating in total disability. Medico-legal considerations in the light of the French legislation.
Université de Bordeaux II, Unités d'enseignement et de recherche des sciences médicales et pharmaceutiques, Bordeaux, France, 1976. 55p. 42 ref.
Static electricity as a design parameter in chemical processing plants.
This article explains, in a simple way, the phenomenon of static electricity and the conditions that can lead to a hazardous situation. Some practical examples (solvent transfer, transfer of dry material from hopper to drum, filling a tank with benzene) are calculated and basic rules for prevention given.
Safeact, July-Sep. 1976, Vol.1, No.5, p.43-52. Illus.
Nikolič N.Lj., Petrovič M.V.
Hazards of electric current and electrical safety
Opasnost i zaštita od električne struje [en serbocroata]
Contents: basic physics (direct and alternating current); instruments for measuring voltage, current, resistance, etc.; sources of electric current (accumulators, transformers, alternators, etc.); special transformers (regulating transformers, welding transformers, etc.); electric power stations and distribution; overhead lines and underground cables; electrical hazards and safety measures (protection against contact voltages and direct contacts in low-voltage and high-voltage installations, insulation, fuses, earthing, connection to neutral, inspection of protective circuits, explosion protection, static electricity and measures against it (Yugoslav regulations), lightning protection, first aid in electrical accidents).
Institut za dokumentaciju zaštite na radu, ul. Višegradska b.b., Niš, Yugoslavia, 1976. 629p. Illus. 79 ref. Price: Din.240.00.
Effects of DC fault currents on differential circuit breakers
Wirkungen von Fehler-Gleichströmen auf FI-Schutzschalter [en alemán]
This article considers the possible case where a core-balance circuit breaker incorporating a summation transformer does not react to a fault current, and analyses the causes of this occurring. Such DC fault currents may occur as a result of faulty insulation or contact with apparatus incorporating a rectifier.
Elektrotechnische Zeitschrift, Ausgabe B, 1976, Vol.28, No.6-7, p.170-172. Illus. 4 ref.
Determination of exposure to electric fields in extra high voltage substations.
Electrophysical effects related to extra high voltage (130-800kV) were surveyed to determine personnel exposure to electric fields. The electric field strengths and electric discharges to personnel were the important electrophysical factors. Instruments for measuring the field strength at grounded surfaces and at nonzero potentials were constructed. A dummy was used for measuring the distribution of capacitive currents to a person. The dummy can also be used to measure the effectiveness of special shielding clothes.
Scandinavian Journal of Work, Environment and Health, Sep. 1976, Vol.2, No.3, p.190-198. Illus. 17 ref.
Danger on tiptoe
Gefahr auf leisen Sohlen [en alemán]
Man has no senses to warn him in good time of the dangers of electricity. Only by knowing the hazards can he protect himself from accidents. The sources of hazard are many: lightmindedness, carelessness, use of equipment not in conformity with regulations, shoddy work, etc. The film shows many examples of such faults, and attempts to render the layman aware of what is important in handling electricity.
Österreichisches Zentrum für Wirtschaftlichkeit und Produktivität, Renngasse 5, 1014 Wien, Austria. Colour film, 16mm, optical sound. 18min.
Protective measures for work on electrical installations
Massnahmen zum Schutz der Elektromonteure [en alemán]
Mesures de protection pour les monteurs électriciens. [en francés]
A large percentage of electrical accidents involve personnel working on electrical installations who underestimate the hazards and fail to take the necessary precautions. In principle the installation should be switched off while the work is being carried out. If live work cannot be avoided, various safety precautions must be taken: protective measures to prevent accidental contact with live parts; protection against the effects of electric arcing; protective measures for work on dead sectors of installations, and on high voltage installations. Examples of typical accidents, indicating cause and possible preventive measures.
Cahiers suisses de la sécurité du travail, Jan. 1976, No.121. 8p. Illus.
The use of aerial baskets in work on power supply lines
Les engins de positionnement ŕ la distribution. [en francés]
After a detailed technical description, the chief hazards of the use of aerial baskets are outlined: crushing of the worker between the equipment or its load and a structure; cuts and perforated wounds; falls; electric shock. Driving the vehicle on the road presents particular problems on account of the high centre of gravity; parking must be subject to very strict rules. When the basket is being used, factors favouring overturning of the vehicle are: loose or sloping surface, load extending beyond the supporting area, contact with an obstacle, etc. Problems related to extension of the basket (position of the vehicle, controls, movements of the boom) are examined. Since basket lifts may be used to lift limited loads, an example of handling a transformer with a pulley-block and electric capstan is described. Reference to the French regulations concerning maintenance, driving on the public highways, use of the basket and training of users.
Vigilance, Mar. 1976, No.53, p.21-36. Illus.
Electricity - The hidden heat.
This film describes how intense heat may be generated by an electrical fault, and how it can set fire to combustible materials nearby; stresses the importance of having work carried out by a qualified electrician; shows the need to test and check installations for deterioration due to age and to oil, water, chemicals, vibrating machinery, etc.; looks at appliances, the starting point for so many fires when they are misused, are of the wrong sort, are faulty, or are not regularly maintained; and explains the proper use of equipment. The action to be taken when a fire is discovered is described, and the 3 types of extinguisher for electrical fires are shown in action.
Fire Protection Association, Fire Prevention Information and Publications Centre, Aldermary House, Queen Street, London EC4N 1TJ, United Kingdom, 1976. 16mm. colour film; optical sound; 21min. Sale price: Ł90.00 (plus VAT); hire rate: Ł12.00 (incl. VAT) per week.
Static electricity - Hazards - Preventive measures and practical examples
L'électricité statique - Risques - Mesures de prévention et exemples d'applications. [en francés]
This brochure is intended for all who have responsible posts in industry. Contents: principles of static electricity; examples of static accumulation phenomena and of the hazards involved (transmission belts, textile industry, paper manufacture and processing, printing, manufacture of photographic films, electrostatic charging of liquids); general preventive measures (air humidification, increasing conductivity of insulating elements, earthing, neutralisation of charges accumulating on non-conducting elements, reducing friction); practical examples.
Editions INRS n°507, Institut national de recherche et de sécurité, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France, Jan. 1976. 82p. Illus. 5 ref.
Konarski S., Łukaszczyk M.
Porażenie prądem elektrycznym [en polonés]
Considerations on the effects of electric current passing through the human body and the resistance offered by the latter. Influence of current frequency; the authors believe that studies carried out up to the present have not yet made this influence quite clear as regards electrical safety. They emphasise the necessity for further research into the phenomenon of electric shock by direct current and alternating current above 100Hz frequency, and consider that Publication 479 of the International Electrotechnical Commission (CIS 75-30) is only a first step towards prevention of the hazard of electric shock.
Bezpieczeństwo pracy, Mar. 1976, No.3, p.4-7. Illus. 5 ref.
Protection measures for electrical fitters
Misure a protezione dei montatori elettricisti [en italiano]
Electrical fitters are directly involved in 20-25% of all electrical accidents reported in Switzerland. This article outlines the protective measures to be taken in work on low-voltage installations, whether live or not, and on high-voltage installations. Typical accidents are described, and the remedies given in each case.
Antincendio e protezione civile, Jan. 1976, Vol.28, No.1, p.32-34. Illus.
Health rules and aspects of protection against the effects of industrial frequency electric fields
Higijenski normativi i neke osobenosti zaštite od dejstva električnog polja industrijske učestanosti [en serbocroata]
The electric field around high-voltage conductors (up to 400kV and more) has harmful effects on the health of exposed workers, who in addition are disturbed by discharges received on contact with conducting structures which become charged by induction. Duration of exposure should be limited according to the intensity of the field (duration limits are tabulated). The article describes various protective measures in detail: screens (including clothing incorporating metallic-scrim), work in an area where the intensity of the field is minimal or reduced by the presence of shielding structures, particular precautions for work in a substation or on underground cable. Recapitulation of basic rules.
Jugoslovenska i inostrana dokumentacija zaštite na radu, 1975, Vol.11, No.3, p.79-88. Illus. 6 ref.
Procházka J., Kvasnička B., Zeman M.
Risk of electrostatic buildup during glue production
Riziko elektrostatických nábojů při výrobě lepidel [en checo]
This study is concerned with glues for the shoemaking industry, prepared from natural and synthetic rubbers or polyurethanes dissolved in commercial grade petrol or various combinations of toluene, acetone and ethyl acetate. The risk of formation of electrostatic charges is present mainly at the mixing stage. After stating the problem, the authors report the preventive measures taken in the undertaking concerned: earthing of all conductive parts of machinery; elimination of polyethylene in the packing material for the glue granulate; injection of solvents tangentially to the mixer wall by a non-sparking metal nozzle; improvement of conductibility of granulates by means of conductive additives which do not affect the properties of the end-product; maintenance of a moderate flow rate of the solvents in relation to the pipe diameter.
Kožařství, 1975, Vol.25, No.12, p.343-344. Illus. 10 ref.
"Hot" work on electrical installations
Arbeiten unter Spannung [en alemán]
The new regulations of the Association of German Electrical Engineers (VDE 0105 - Work on heavy current installations; entry into force, 1 May 1975) draw a distinction between work which has to be carried out on live installations, work which may be freely carried out on these installations, and work which may be carried out on these installations if circumstances so require. Detailed methods for each of these 3 categories of work (type of operation and level of skill of personnel involved, according to voltage range) are presented in tabular form. Voltages between 42 and 500V are particularly important from the practical point of view. Reasons justifying work on live installations; responsible personnel; provisions concerning tools and protective equipment (in particular, marking of insulating rods and other special equipment, insulating tools and protective clothing). The article concludes with a number of examples of work on live installations.
Sicherheitsingenieur, Nov. 1975, Vol.6, No.11, p.516-526 and No.12, p.586-591. Illus.
Measurement of earth systems in high-voltage installations
Die Bemessung der Erdung in Hochspannungsanlagen [en alemán]
Calculation of the fault current and earth current, essential parameters for determining the voltage to earth, is demonstrated. Other factors to be determined: specific resistance of the earth electrodes and the earth resistance. It is recommended that the efficacy of earthing be controlled by measurements. Instructions for measurement and for earthing.
Elektrotechnische Zeitschrift, Ausgabe A, 1975, Vol.96, No.9, p.418-423. Illus. 17 ref.
Calculation and measurement of the characteristics of earthing installations
Dimensionieren und Messen von Erdungsanlagen [en alemán]
Writing with long experience of electricity production and distribution units, the author first comments on the amendments concerning earthing in the Swiss ordinance on heavy current and after a few general remarks goes on to deal with the following aspects: electrical resistance of the earth; different types of earth connections; measurement of voltage distribution and of earth resistance; influence of the depth of electrode placement in the earth on the contact and step voltage; calculation of artificial earthing installations; combination of various earth electrodes for control of the potential; effect of an electric current on the earth connection; materials for earth electrodes and problems of corrosion; calculation and measurement of loss currents to earth in 16kV installations.
Technische Rundschau, 1975, Vol.67, No.36, p.3-7, No.38, p.39-41, No.40, p.25-27, 31 and No.43, p.13-15. Illus.
Currents passing through the body, limits of contact voltage and protective measures
Körperströme, Berührungsspannungsgrenzen und Schutzmassnahmen [en alemán]
After an introductory section on cardiac function, the excitation phase and ventricular fibrillation, the author refers to animal experiments and accident investigations in a study of the minimum duration of exposure to an electric current, the fibrillation threshold, and the current intensity ranges. Conclusions relating to the hazard ranges and the efficacy of high-sensitivity differential circuit breakers. In extreme conditions (brief duration of exposure in the critical T-wave phase, resistance of the fault circuit less than 500Ω), the differential circuit breaker cannot prevent a fatal outcome. Differential circuit breakers should therefore not be used without a protective conductor.
Elektrotechnische Zeitschrift, Ausgabe B, 1975, Vol.27, No.17, p.461-464. Illus. 10 ref.
De Parny R., Obe J.P.
Live work with high and very high voltage - Equipment and methods
Les travaux sous tension en haute et trčs haute tension - Matériels et méthodes [en francés]
In this abundantly illustrated article, the authors briefly describe the insulating elements of tools for live work, then the functions and characteristics of: hand tools, coupling rods with tensioning clip, equipment for handling suspension and tension insulators, equipment for positioning the operator (insulating ladder, extension ladder, seat, boom). Live work methods: work at a distance (using tools attached to the ends of insulating rods) and equipotential work (the climber is insulated from the earth by an insulating positioning device and raised to the potential of the live part he is working on). Live work conditions (electrical reliability of the system, climatic conditions).
Vigilance, Nov. 1975, No.52, p.21-34. Illus.
Electrical hazards in underground bituminous coal mines.
Results of a study of 1,404 accident and injury reports for 1972 and 1973 are tabulated: type of accident, material cause, part of body injured. More than 96% of all electrical accidents resulted from electric arcs, electrically generated heat, and electrocution and shock. Cables and trolleys were the greatest cause of electric arcs and burns. A further aspect treated is that of mine fires caused by electrical sources. Some technical safety measures and special training are recommended for the prevention of this type of accident.
MESA Informational Report 1018, Mining Enforcement and Safety Administration, Technical Support Center, 4800 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA, 1975. 5p. 1 ref.
Safety during work in the vicinity of live parts
Arbeitsschutz bei Arbeiten in der Nähe von unter Spannung stehenden Teilen [en alemán]
This booklet sets out the precautions to be taken during work on live parts in indoor and outdoor installations and on overhead lines. Definitions of the main terms are followed by a description of safety measures. Instructions are given regarding determination and marking the limits of the workplace and requirements to ensure its safety. The measures and precautions to be taken in each case by workers and the role of supervisory staff are specified.
Verlag Tribüne, Am Treptower Park 28-30, x 1193 , 1975. 44p. Illus. 12 ref. Price: M.0.80.
German Standards Committee (Deutscher Normenausschuss), Berlin (Westsektoren); German Electrotechnical Commission (Deutscher Elektrotechnische Kommission), Frankfurt am Main, May 1975.
Rule of the Association of German Electrical Engineers concerning the operation of power installations
VDE-Bestimmung für den Betrieb von Starkstromanlagen [en alemán]
This rule applies to the operation of electrical installations in conformity with regulations VDE 0100 and 101 (rated voltage below and above 1kV respectively). It also applies to construction, assembly and repair work carried out in the vicinity of heavy current installations. Definitions and general requirements are followed by provisions concerning the following points: operation of electrical installations, maintenance and cleaning; disconnection before all interventions, and checks to ensure that the installation is "dead"; switching on after conclusion of the work; "hot" work; work near live installations; equipment for prevention of accidents and fire fighting equipment.
Beuth Verlag GmbH, Burggrafenstrasse 4-7, 1 Berlin 30. 38p. Illus. Price: DM.21.00.
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