Other Pressure Hazards

debris, and other particles can be blown by compressed gas into an eye and rupture it or through the skin like a bullet. Occupational Safety and Health Administration (OSHA) standards permit compressed air to be used for cleaning purposes if its pressure is less than 30 psi and if personal protective equipment is used. 

There have been cases in which compressed air entered the circulatory system through cuts in the skin. Since the skin breathes through pores, compressed air can pass through the skin and into the blood stream. In a Massachusetts plant, a woodworker, covered with sawdust held a compressed air nozzle 12 inches away from the palm of his hand and opened the valve to blow the sawdust off. Within seconds, his hand swelled up to the size of a grapefruit. 

Finding gas leaks (pressure hazards) can be difficult. After a gas has leaked into the ocean of air around it, obvious symptoms of the leak (odor or a cloud) may disappear. Several methods of detecting gas leaks are  

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Compressed gases, therefore, present a unique hazard from their potential physical and chemical dangers. Unless cylinders are secured they may topple over, cause injury to operators, become damaged themselves and cause contents to leak. If the regulator shears off, the cylinder may rocket like a projectile or torpedo dangerously around the workplace. Other physical hazards stem from the high pressure of a cylinder s contents, e.g. accidental application of a compressed gas/air hose or jet onto an open cut or wound, whereby the gas can enter the tissue or bloodstream, is particularly dangerous. 

While it is important to take proper precautions (see Appendix 2), properly built equipment offers few hazards if relatively small quantities of liquids are used under pressure. The energy stored in a compressed liquid is of the order of 0.2-0.5 kJ mor kbar" this is much less than in a gas. In the event of the catastrophic failure of a vessel, only around 10 per cent of the liquid would need to escape to reduce the pressure to the atmospheric value, and double-walled vessels are unlikely to suffer a failure of both cylinders. The author has experienced the failure of a piston-cylinder apparatus which led to nothing more than a sudden depressurization. On the other hand, hazards may arise from the low-pressure side, which is likely to be carrying oil at 500 bar or more a pin-hole jet at this pressure can penetrate the human body. The valve threads may become worn and the stems may then be forcibly ejected. So hose connections should be inspected and renewed regularly and, where possible, they should be shielded from personnel, the valves should be mounted with the stems pointing away from the operator, and the guidelines set out in the code of practice (see Appendix 2) should be followed. 

These costs and other pressures are now evident throughout the supply chain for a chemical product - from the increasing costs of raw materials, as petroleum becomes more scarce and carbon taxes penalize their use, to a growing awareness amongst end-users of the risks that chemicals are often associated with, and the need to disassociate themselves from any chemical in their supply chain that is recognized as being hazardous (e.g. phthalates, endocrine disrupters, polybromina-ted compounds, heavy metals, etc. Fig. 1.1-2)... 

Instructions Please list each major industrial or other type hazard not previously identiSed. Consider hazards such as electromagnetic radiation electrical, mechanical, thermal, or pressurized equipment or other hazards that could cause or contribute to serious injuries. For example, an industrial hazard could be electrocution caused by worker or procedural error. Additional notes could include a discussion of safeguards that are in place to prevent such an event. Do not list trivial hazards (i.e., diose events tlmt could only produce minor injuries). 

Training People who work around compressed air lines, hydraulic systems, and other pressurized fluid and gas equipment should leam about the hazards. They should learn not to place fingers or hands against a fluid stream and they should learn not to place the stream near anyone else. Protective gloves and clothing may help reduce injection injuries. 

Besides the strain gauge type transducer, other pressure transducers may employ variable capacitance, variable inductance, or piezoelectric crystal sensors to detect pressure changes. The low level output pressure transducer can be used in systems controlling flammable and other hazardous gases if the system has been designed such that the electronic power levels being used to excite the transducer remain very low. They can even be used in Class I, Division II areas if the proper intrinsic safety barriers are used in conjunction. Like the pressure gauge, the transducer may have a... 

Avoid - cancel or delay the activity that involves the risk, or do not operate, equipment that involves the risk. Make processes inherently safer by eliminating hazards (e.g. eliminate energy sources such as pressure, heat, potential energy, kinetic energy, etc. Do not use hazardous materials and materials that can generate hazardous energy. Use other, less hazardous, materials in place of more hazardous materials. 

So far the emphasis has been on substituting hazardous materials or using less, i.e., intensification. Let us now consider use of hazardous materials under less hazardous conditions, i.e. at less extreme temperatures or pressures or as a vapor rather than superheated liquid or diluted, in other words, attenuation. ... 

Low pressure. Low pressures are not in general as hazardous as the other extreme operating conditions. However, one particular hazard that does exist in low-pressure plants handling flammable materials is the possible ingress of air with the consequent formation of a flammable mixture. 

Primary human skin irritation of tetradecanol, hexadecanol, and octadecanol is nil they have been used for many years ia cosmetic creams and ointments (24). Based on human testing and iudustrial experience, the linear, even carbon number alcohols of 6—18 carbon atoms are not human skin sensitizers, nor are the 7-, 9- and 11-carbon alcohols and 2-ethylhexanol. Neither has iudustrial handling of other branched alcohols led to skin problems. Inhalation hazard, further mitigated by the low vapor pressure of these alcohols, is slight. Sustained breathing of alcohol vapor or mist should be avoided, however, as aspiration hazards have been reported (25). 

Properties of other higher a-olefins and those of some commercially significant cycloolefins are given in Table 2. These monomers are fiquids at ambient temperature and pressure. They are highly combustible and can form explosive mixtures with air. The primary health hazards presented by these monomers are associated with inhalation or prolonged skin contact that can cause irritation. 

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