Static risks

Considering these scores, the equipment is categorized into five priority levels (High, Medium, Low, Grey List, and Non-Inclusion into the Medical Equipment Management Program). The four static risk categories are ... 

The aggregate static risk score is calculated as follows ... 

An example of a pure —or static - risk concerns a build-up of combustible material in the corner of a large distribution warehouse. If a source of ignition is present in the vicinity, then the risk of fire spread is greatly enhanced by the build-up of combustible material, thus posing the threat of a large loss of stock caused by fire. There will also be consequential loss resulting from the fire to consider, e.g. loss of profit on goods in stock loss of market share etc. 

The SESAR safety assessment approach typically uses static risk modelling techniques safety criteria and objectives are identified based on accident incident models and further safety requirements are derived using Fault Trees, Failures Modes and Effects Analysis or similar techniques. This section presents criteria to identify specific cases where DRM application is required. 

It is believed that to avoid any risk of explosion, the electrical conductivity of jet fuel should fall between 50 and 450 pS/m. This level is attained using anti-static additives which are metallic salts (chromium, calcium) added at very low levels on the order of 1 ppm. 

Mixing cellulose esters in nonpolar hydrocarbons, such as toluene or xylene, may result in static electricity buildup that can cause a flash fire or explosion. When adding cellulose esters to any flammable Hquid, an inert gas atmosphere should be maintained within the vessel (132). This risk may be reduced by the use of conductive solvents in combination with the hydrocarbon or by use of an antistatic additive. Protective clothing and devices should be provided. 

There are no available data to establish whether nonconductive, low viscosity chemical products such as ethyl ether similarly display hyperbolic relaxation below about 2 pS/m, or even whether this phenomenon is a practical reality for such liquids. Should Ohmic relaxation behavior continue to much less than 0.5 pS/m the risk of static accumulation would be enhanced compared with petroleum distillates. 

All-plastic nonconductive pipe such as polyolefin is not recommended for handling nonconductive or semiconductive liquids except where it can be shown that the advantages outweigh any risks associated with external static ignition or leakage via pinholes, or where tests have demonstrated that the phenomena will not occur. Burying an all-plastic pipe prevents external... 

Since velocity varies with the inverse square of pipe diameter d, an important consideration is the selection of pipe diameter. For any given velocity-diameter product, larger pipe diameters allow larger flow rates. Since occasional static ignitions in road tankers may occur at nr/ = 0.38 mVs, smaller values might be considered for nonconductive liquid transfer depending on risk tolerance. 

The fire risk from static ignition increases with the volume and volatility of flammable liquid handled. Hence, the smallest volume container capable of... 

Inherent or possible explosion risks (e.g. static discharge associated with extinguishant discharge). 

Even if a static spark ignites a mixture of flammable vapor and air, it is not really correct to say that static electricity caused the fire or explosion. The real cause was the leak or whatever event led to the formation of a flammable mixture. Once flammable mixtures are formed, experience shows that sources of ignition are likely to turn up. The deliberate formation of flammable mixtures should never be allowed except when the risk... 

Disadvantages may arise because the behavior observed may not be fully realistic. A static simulation, for instance, may not reveal the true nature of operators dynamic interaction with the system. There is also the possible disadvantage of behavior in a simulator not fully replicating that found in the real situation. This can happen because of the absence of real stressors found in the actual task, for example, risk to life, criticality of the process, and presence of other workers and supervisors. 

Hazard, i.e. the potential of the material to cause injury under certain conditions (flammability, explosion limits in air, ignition and autoignition temperatures, static electricity (explosions have occurred during drying due to static electricity), dust explosion, boiling point, fire protection (specification of extinguishers, compounds formed when firing), R S (nature of special risk and safety precautions). Table 5.2-5 lists hazards associated with typical chemical reactions. 

As probabilistic exposure and risk assessment methods are developed and become more frequently used for environmental fate and effects assessment, OPP increasingly needs distributions of environmental fate values rather than single point estimates, and quantitation of error and uncertainty in measurements. Probabilistic models currently being developed by the OPP require distributions of environmental fate and effects parameters either by measurement, extrapolation or a combination of the two. The models predictions will allow regulators to base decisions on the likelihood and magnitude of exposure and effects for a range of conditions which vary both spatially and temporally, rather than in a specific environment under static conditions. This increased need for basic data on environmental fate may increase data collection and drive development of less costly and more precise analytical methods. 

Verro et al. [53] evaluated the risk associated with the presence of alachlor herbicide in surface waters (released by drift and runoff) from Lombardia region (Northern Italy). They applied a GIS-based model for representing the obtained PECs in risk maps showing a static image of a worst-case simulation in each river subbasin. 

Dry metal-impregnated charcoal catalyst was being added from a polythene bag to an aqueous solution under nitrogen. Static so generated ignited the charcoal dust and caused a flash fire. The risk was eliminated by adding a slurry of catalyst in water from a metal container. 

The precautionary approach (PA) is an important element of environmental law that is used to address a potential risk whether or not that risk can be demonstrated or its consequences identified. The static use of a sole, generally accepted definition of the PA is extremely difficult, since this cannot meet the multitude of needs in important legislative tools introduced in many conventions designed to protect biodiversity. The way out will be a more discursive model, a model that allows for adaptation to specific conditions and which enforces solution-oriented procedures. 

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