Explosion protection document

Besides other more or less general obligations, i. e. taking necessary, preferred technical measures and providing supervision to protect the safety and health of workers, the employer has to draw up an explosion protection document. This obligation is independent of the number of employees, firstly, it contains information on the risks that have been determined and assessed and what measures have been taken. Secondly, it requires the classification of places having an explosion risk into zones. In annex 1, explosive zones are defined (see Table 6.3). 

Drawing up an explosion protection document (article 8 of the directive)In the scope of the obligation to the assessment of explosion risks (article 8 ofthe directive) the employer must draw up an explosion protection document and keep it up to date. 

The explosion protection document must demonstrate in particular... 

Before vacuum pumps are put into operation, the operating company of a vacuum pump has to examine and assess the explosion risks which can be caused in the connection with the installation site and the processes applied. He must prevent or limit the formation of explosive areas. Remaining explosive areas have to be assigned to zones. Possible ignition sources in the zones must be avoided. The work equipment for the required equipment categories, for example explosion-protected vacuum pumps of the respective category, has to be selected. The results of the risk assessment, the applied protective measures, the zone classification and the remaining risks have to be recorded in the explosion protection document. 

The employer must draw up an Explosion Protection Document to demonstrate that the risks have been assessed and to explain the precautions to be taken to control the risks. He must also coordinate the implementation of health and safety measures with other employers. 

Employers in control of hazardous areas need to determine the locations and extents of these zones in each of the hazardous areas, an exercise known as hazardous area classification. At present, in 2001, there is no specific legal duty to carry out hazardous area classification, apart from the general duties to carry out risk assessments and, in the context of mines, in Regulation 19 of the Electricity at Work Regulations. However, the Protection of Workers Potentially at Risk from Explosive Atmospheres Regulations expected to be enacted soon, will contain specific provisions relating to area classification and the need to record the area classification information in an explosion protection document. 

Finally, it must be pointed out that all explosion protection devices or systems used in practice may be used only when their pressure rating, flameproof, and functional testing have been proved by competent bodies and their test results including the limits of application are documented in a type test certificate. 

Table 3.12 summarizes IEC members and associates. Within the IEC, technical committees and subcommittees are involved in standardization work covering all aspects of electrical engineering, e.g. insulating materials, semiconductors, wires and cables, lamps, motors, generators, transformers, and, of special interest, electrical apparatus for explosive atmospheres. This is the responsibility of Technical Committee TC 31 and eight subcommittees (see Table 3.13). Table 3.14 gives a survey of IEC documents and standards covering the field of explosion protection of electrical apparatus. 

Basics of Explosion Protection, STAHL Brocheure http //www.rstahl.com/fileadmin/Dateien/ tgus/Documents/ExProtection Glohah America-Basics.pdf. 

Certification, routine testing, and documentation are major responsibilities of manufacturers of explosion protected apparatus. Design, manufacturing, and compliance with approved design are also responsibility of the manufacturer. 

Vacuum pumps of category 2 which pump from zone 1 have to be subjected by the manufacturer to an internal control of production according to annex Vlll of the directive. In addition, the manufacturer has to deposit a technical documentation for the vacuum pump at a Notified Body, including a risk assessment, ignition hazard assessment and notes for the implemented measures to maintain the explosion protection. 

In a flash fire, a gas cloud or plume fonns and moves in a downwind direction. Subject to contact witli an ignition source, a wall of flame will flash back to the vapor source, sometimes witli explosive force. The beliavior of flash fire flames is not well documented. It is generally assumed tliat a flash fire will spread tliroughout tlie vapor cloud emitted and tliat it can be calculated by gas outflow dispersion. It is generally assumed tliat tlie fire is lethal to anyone within the contours of tlie cloud who is not wearing special protective gear. ... 

Most reactions of bromine are highly exothermic which can cause incandescence or sudden increase in pressure and rupture of reaction flasks. There are a number of cases of explosions documented in the literature. (NFPA. 1986. Fire Protection Guide on Hazardous Materials, 9th ed. Quincy, MA National Fire Protection Association) Reactions of liquid bromine with most metals (or any metal in finely divided state), metal hydrides, carbonyls and nitrides can be explosive. Many oxides and halides of nonmetals, such as nitrogen triiodide or phosphorus trioxide, react explosively or burst into flame in contact with liquid bromine. 

The choice of the zero point is an essential element in the safety file of a nuclear test. However, this file covers many other aspects. It specifies the conditions for performing the test in conformity with the defined principles, in order to avoid accidents and ensure the radiological protection of the personnel and the environment. It must satisfy both the severe criteria for defining the explosion point and the many rules governing operational implementation. After examination and approval, this file becomes the reference document for the test in terms of safety. Any subsequent change necessitates a new examination. 

Companies involved in processing certain hazardous chemicals are required to take additional precautions to protect the employees. The purpose is to prevent or minimize the consequences of catastrophic releases of toxic, reactive, flammable, or explosive chemicals that may result in toxicity, fire, or explosion hazards. They are required to document what the company has done in regard to process safety if... 

The entire incident is well described and well documented in a 15-page report by David Chung of the US Environmental Protection Agency (EPA). David Chung s paper is entitled, Explosion and Fire at Powell Duffryn Terminals - Savannah, Georgia. There are many lessons that can be learned from this incident. This text will address lack of effective MOC, understanding of carbon beds, proper equipment layout, and caution with incompatible chemicals [10]. 

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