(47ac) Analysis of the Potential Energy Sources of Risk of Tools in Presence of Hazardous Area in Segment of OIL and Gas

1 Brief justification

The use of equipment with rotating mechanical parts, as well as maintenance and repair of machines and installations within hazardous areas are routine activities of a modern industry. One of the methods usually adopted explosion protection refers to the use of hand tools for non-ferrous materials, usually bronze, also known as non-sparking hand tools.Studies by Americam Petroleum Institute (API / USA - United States of America) and European Norms have disagreements as to the risks involved in sparks produced by tools and mechanical equipment. While the API demonstrates that even mechanical equipment operations at high speeds and high contact pressure, it is extremely difficult to produce sparks capable of igniting vapors and gases from the oil industry and concludes that the risks involved are low for oil vapors, the IEC (International Electrotechnical Commission) begins to formulate a set of international standards on the subject. These standards will be adopted in the future in Brazil and may impact the operations of our industry, particularly the oil industry.

 2. Detailed Rationale

 Ongoing investigations conducted by the Safety in Mines Research estalishment of England in the late 20th century, sought to discover the causes of fires in the mining industry. In the article entitled "Gases and Vapors - Review is Ignition of Flammable Gases and Vapors by Friction and Impact" published by F. Powell, he reports the work done in investigating more than 82 accidents, but only some of the references involving hand tools and the author avoided drawing any conclusion on the subject.

 Already in the 1930s, engineers fire protection in the oil industry began to question the rationale for recommending the use of special tools nonferrous rather common steel tools in operations in the oil industry. Engineers signaled that although there numerous chances to produce sparks when the violent contact of steel objects against other objects of steel, fire cases attributable to such causes were negligible.

 A study presented at the Session on Fire Protection Group at the annual meeting of the American Petroleum Institute, in 1941, described a series of tests which they did during the last 15 years, which proved to be very unlikely that the ignition of vapors of oil could be caused by sparks produced by contact with stainless steel with abrasive wheel, or even with mechanized equipment. The nature of the sparks was discussed and shown that any material harder than steel, the same material sparkling, could produce sparks when it strikes against it. Concluded that the insistence on the use of special tools not flashing creates a false sense of security, at the expense of other more important measures of safety protection against fire, and comprehensive rules covering the use of such tools were not recommended and against the best interests the industry.

 The use of non-sparking tools was not universal throughout the industry until 1941, but then the presentation of the article Group Session on Fire Protection, many companies have started a program to phase out the use of special tools. However some companies associated API believed that additional research was desirable to develop an opinion by an independent institution. In 1948 had already obtained the necessary funds and hired in 1950 to conduct a series of tests at Underwriters Laboratories Inc, Chicago, sponsored by the American Petroleum Comittee on Prevetion Accident and Fire Protection.

 Within three years, little has been done in addition to confirming the obvious conclusion that even with mechanical appliances operating at high speeds and high contact pressure, it is extremely difficult to produce sparks capable of igniting vapors from petroleum. Means for correlating the results of these assays with the properties of the sparks produced using common hand tools have not been developed. Thus, it was decided to terminate the contract. The American Petroleum Comittee on Prevetion Accident and Fire Protection has reviewed the situation and proposed document preparation "Sparks from Hand Tools", which was approved for publication by the Safety Comittee of the Board Directors, these studies have been consolidated in the document API 2214 of February 3, 1956.

The Institute of Petroleum (IP - England) clearly begun to consider the importance of sparking hand tools as a source of ignition in the early '60s, when he sent this concern to study the Comittee on Industrial Fires and Explosion of the Fire Research Board. The studies were conducted between 1961 and 1963. The article entitled "The Relative Hazards in the Use of Ferrous and Non Sparking Tools in the Industry Pertoleum" by HG Riddlestone and A. Bartels, included a comprehensive review of published information, but the study did not contain any new experimental evidence. An introductory note prepared by the Comittee of the Petroleum Engineering Intitute indicated that additional experimental work were not necessary, accepting the conclusion that of non sparking tools do not make a significant reduction in the risk of ignition of vapors of oil by force friction sparks, in comparison with the tools coming from ferrous materials. But the members of the IP were cautioned not to consider this conclusion to apply to gases incendive more easily than the vapors of oil, as an excuse for failing to ensure the absence of ignitable concentrations of flammable gases or vapors, or not to take other precautions when applicable of performing mechanical work.

The American Petroleum Institute (API) issued in July 2004, the fourth edition of the document “API RP 2214 - Properties of ignition sparking hand tools”, which concludes that nothing essentially new has been learned since the publication of the first paper in 1596. That complements recent publications such as the NFPA's Fire Protection Handbook, report the same findings described 40 years ago.

The position issued by the International Safety Guide for Oil Tankers & Terminals (ISGOTT), in its fifth edition (2008), quoted in item 4.5.2 - Hand tools, the use of hand tools such as scrapers and picadeiras, preparation and maintenance of steel may be authorized without the Hot Work Permit. Their use should, however, be restricted to the deck area and facilities are not connected to the charging system. The work area should be cleaned and degassed combustible materials. The ship should not be running cargo operations, ballast supply, tank cleaning, purging or inerting. The tools made of non-ferrous metal, called non sparking, have only less likely to create a spark ignitiva and due to relatively lower hardness of ferrous metals, not as efficient as their counterparts made material Ferrous. Particles of sand, concrete and stony other substances may be embedded in the working surface or edge of the tool with the impact against ferrous metal or other hard metals can produce sparking. The use of tools for nonferrous metals is therefore not recommended. This is equivalent to running a flint.

The IEC on August 8, 2008, issued the document 31M/14/DC proposing the member countries the creation of IEC SC 31M. In your text it is described, based on the European standard EN 13463-1:2008, the risk assessment is essential to assess the potential ignition sources generated by mechanical equipment and conditions under which they may occur. This is the main difference to the standards of electrical equipment. In the operation of combustible dusts, industries need to recognize that many types of process contain a potentially explosive atmosphere of considerable extent during operation, and high power and energy of mechanical equipment may not consider the level of security that would be expected from an electric in area of concentration of explosive mixture for continuous periods or long periods. The assessment of risk of ignition can be helpful in the decision to combine prevention and protection features necessary. Therefore, it is proposed that a set of standards is designed for non-electrical equipment and components. This Standard will specify the basic methods and requirements for design, construction, testing and marking of electrical equipment is not for use in explosive atmospheres of gas, vapor, mist or dust. Such atmospheres may exist inside the equipment. In addition, the surrounding environment can also penetrate the equipment due to natural respiration produced as a result of fluctuations in pressure or temperature inside the operating equipment. The proposed establishment of this technical committee was approved at the next annual meeting.

 At the general meeting of the Technical Committees of the IEC ¹ 31 - Equipment for explosive atmospheres, held in October 2008, in São Paulo, Brazil, were present 63 delegates representing 22 National Committees for Standardization. This Subcommittee SC 31M TC-31 IEC, represents a "joint venture" between organizations ISO and IEC in support of international technical standardization. The SC-31M are developing standards - numbered in the series IEC 80079 - and are called "non-electrical equipment and protective systems for explosive atmospheres".

3 - Conclusions

The tests will begin in next november (local: CEPEL - Research Laboratories of Eletrobras of  Atmospheres Explosive - AP4) and we want do the presentation to this AIChE event, in first hand, with the preliminaries results of this work