Explosion protection properties

Having carried out an area classification exercise, the electrical equipment to be installed in the area must then be selected for its explosion protection properties. There is a range of options to choose from, with a variety of protection techniques employed. Each of the techniques, bar one, is described in detail in a European harmonised standard and is allocated a designation letter, mainly for ease of labelling. The following text summarises each of the techniques, and identifies its letter designation and appropriate construction standard. 

In the beginnings of the petroleum industry, usually very limited safety features for fire or explosion protection were provided, as was evident by the many early blowouts and fires. The industry became known as a "risky" operation, not only for economic returns, but also for safety (loss of life and property destruction) and environmental impacts, although this was not well understood at the time. 

The very poor colour rendering property of low pressure sodium vapour lamps is due to the narrow-band emission of the Na lines (at a wavelength of 589.0 and 589.6 nm). Low pressure sodium vapour lamps are generally not within the scope of the standards for explosion protected luminaires... 

Foam mitigation systems currently used by Explosive Ordinance Disposal (EOD) units would be effective for protecting property from the blast used to destroy CWM, but would require subsequent clean-up of chemical agent, water and surfactant. 

Directive 94/9/EC (ATEX 95) to approximate the laws of the Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres governs requirements for products intended for the use in explosion risk areas. Directive 1999/92/EC (ATEX 137) on minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres regulates the minimum requirements for explosion protection at work places and for the safe use of products. The ATEX 95 therefore deals with the properties of the products to be used in explosion risk areas while ATEX 137 regulates their operation and other operational measures for explosion protection. 

There are several types of emergencies. Some result from the forces of nature. Some involve fire and explosion. Some involve system failures. Some emergencies entail traffic or transportation problems. Some result from the behavior of people. For others, there are police, military, and public safety actions to assist people and protect property. 

At first, general explanations to the explosion protection are given. The basic properties and characteristics of an explosive atmosphere and the dependences between the particular safety characteristics are explained. 

If explosions cannot be excluded for sure, technical measures which limit the effects of an explosion to a harmless extent (no personal injuries, tolerable damages to property) (tertiary or constructive explosion protection). 

Respiratory inlet covering the portion of a respirator that forms the protective barrier between the user s respiratory tract and an air-purifying device or breathing air source Response activities that address the direct effects of an incident includes immediate actions to save lives, protect property, and meet basic human needs Response force the people who respond to an act of aggression depending on the nature of the threat, the response force could consist of guards, special reaction teams, military or civilian police, an explosives ordnance disposal team, or a fire department. 

While applying various porous inhibitors for HAM and especially HOM explosions, the probable dependence of decreasing protective properties with initial pressure growth must be taken into account. Efficiency of fire-resistant blockers and detonation inhibitors should be tested within the pressure range that may occur... 

Often the polymers have to be briefly heated up to temperatures around 200°C-250°C to improve their protective properties. In this case, the explosive evaporation of adsorbed moisture can cause considerable mechanical strain at the polymer/substrate interface, which in turn might result in breakage of the polymer/substrate composite at the interface. Interestingly, in most cases, the failure occurs not directly at the interface but near the interface [117-124]. For this kind of adhesive breakage near the interface, several nanometers of polymer coating are usually still covering the substrate. It seems that the molecular forces between substrate and polymer are not crucial for the failure, but the transition zone from the substrate into the polymer bulk plays the key role. 

When dispersed as a dust, adipic acid is subject to normal dust explosion hazards. See Table 3 for ignition properties of such dust—air mixtures. The material is an irritant, especially upon contact with the mucous membranes. Thus protective goggles or face shields should be worn when handling the material. Prolonged contact with the skin should also be avoided. Eye wash fountains, showers, and washing faciUties should be provided in work areas. However, MSDS Sheet400 (5) reports that no acute or chronic effects have been observed. 

Dow Fire and Explosion Index. The Dow Eire and Explosion Index (3) is a procedure usehil for determining the relative degree of hazard related to flammable and explosive materials. This Index form works essentially the same way as an income tax form. Penalties are provided for inventory, extended temperatures and pressures, reactivity, etc, and credits are appHed for fire protection systems, process control (qv), and material isolation. The complete procedure is capable of estimating a doUar amount for the maximum probable property damage and the business intermptionloss based on an empirical correlation provided with the Index. 

Personnel involved in the handling of methanol require eye and skin protection from the irritating properties of methanol in the event of a spill. Contact lenses should not be worn, since plastic lens materials may absorb and concentrate methanol against the eye. Additional respiratory protection is not required with adequate local explosion-proof ventilation. 

A significant advantage of the PLM is in the differentiation and recognition of various forms of the same chemical substance polymorphic forms, eg, brookite, mtile, and anatase, three forms of titanium dioxide calcite, aragonite and vaterite, all forms of calcium carbonate Eorms I, II, III, and IV of HMX (a high explosive), etc. This is an important appHcation because most elements and compounds possess different crystal forms with very different physical properties. PLM is the only instmment mandated by the U.S. Environmental Protection Agency (EPA) for the detection and identification of the six forms of asbestos (qv) and other fibers in bulk samples. 

Secure the scene get medical attention to tlie injured. Move bystanders aw ay to a safe distance. Inform print and electronic media. Protect people and property as necessary. Be aware tliat explosive materials and toxic vapors can do damage at a great distance... 

Precautions also have to be instituted to protect against the inherent properties of the cylinder contents, e.g. toxic, corrosive, flammable (refer to Table 8.1). Most gases are denser than air common exceptions include acetylene, ammonia, helium, hydrogen and methane. Even these may on escape be much cooler than ambient air and therefore slump initially. Eventually the gas will rise and accumulate at high levels unless ventilated. Hydrogen and acetylene can form explosive atmospheres in this way. 

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