Hazard to personnel

Hazards of Production. In most zinc mines, zinc is present as the sulfide and coexists with other minerals, especiaHy lead, copper, and cadmium. Therefore, the escape of zinc from mines and mills is accompanied by these other often more toxic materials. Mining and concentrating, usuaHy by flotations, does not present any unusual hazards to personnel. Atmospheric poHution is of Httle consequence at mine sites, but considerable effort is required to flocculate and settle fine ore particles, which would find their way into receiving waters. 

Conclusions The use of an inert atmosphere can virtually eliminate the possibility of explosions and fire with flammable materials. However, inerting systems can be quite expensive and difficult to operate successfully and can be hazardous to personnel. Before using inert systems, alternatives should be explored, such as using nonflammable materials or operating below the flammable range. 

The selection of materials to be used in design dictates a basic understanding of the behavior of materials and the principles that govern such behavior. If proper design of suitable materials of construction is incorporated, the eqiiipment should deteriorate at a uniform and anticipated gradual rate, which will allow scheduled maintenance or replacement at regular inteivals. If localized forms of corrosion are characteristic of the combination of materials and environment, the materials engineer should still be able to predict the probable life of equipment, or devise an appropriate inspection schedule to preclude unexpected failures. The concepts of predictive, or at least preventive, maintenance are minimum requirements to proper materials selection. This approach to maintenance is certainly intended to minimize the possibility of unscheduled production shutdowns because of corrosion failures, with their attendant possible financial losses, hazard to personnel and equipment, and resultant environmental pollution. 

Continuous monitoring is necessary on critical machines where problems can develop rapidly and have severe financial consequences. Typical machines in this category are unspared process compressors. Remotely located machinery such as pipeline gas compressors also require continuous monitoring. Also, continuous monitoring may be dictated by safety considerations. Even though the cost of a failure is small, machines should be continuously monitored if a failure will result in hazards to personnel. Figure 8-38 depicts a typical continuous monitoring system. 

When primary fume capture is performed by the enclosure, furnace off-gas combustion efficiency is lower than experienced by furnace direct evacuation control. The off-gas, rich in carbon monoxide (CO), rises from furnace roof openings and partially burns and cools with enclosure air. Significant levels of CO have resulted in the enclosures and exhaust ducting from this type of combination. These levels are not explosive but present a potential hazard to personnel working in the enclosure or in downstream fume cleaning equipment. 

Minor hazard to personnel Orderly process shutdown necessary... 

Other methods of cleaning iron and steel include immersion in molten sodium hydride and cathodic treatment in molten caustic soda. These methods may be hazardous to personnel, and should not be carried out by the uninitiated, or without professional supervision. 

This chapter of the book presents papers dealing with the identification and mitigation of potential hazards to personnel and facilities, with the development of personnel protection schemes and with the safe siting of facilities. 

Whenever possible waste vapors or gases should be disposed of through the facility flare system or reinjected into the production process for recovery. Non polluting materials such as steam can be freely vented to atmosphere if they do not pose bum hazards to personnel. 

COz is a nonflammable gas, therefore it does not present a tire or explosion hazard. The gas is generally considered toxic but will displace oxygen in the air, since it is 1.5 times heavier that air it wall settle and air supplies will be pushed out of the area. The CO2 gas is considered an asphyxiation hazard to personnel for this reason. Since the gas is odorless and colorless it cannot be easily detected by human observation in normal environments. Fire protection CO2 gas is normally stored under high pressure as a liquid and expands 350 times its liquid volume upon release. 

In small rooms where high pressure CO2 storage bottles are kept, it is apparent that with a 350 expansion ratio, the room could easily be a hazard to personnel from system leakages. 

In small rooms where high pressure CO2 storage bottles are kept, it can be readily realized that with a 350 expansion ratio, the room would easily be a hazard to personnel from system leakages. A calculation could be performed which would identify the amount of potential CO2 build up (i.e., percent CO2 concentration) from the immediate and complete (i.e., leak)... 

Biosafety Level 2 (BSL-2) Similar to Biosafety Level 1 and is suitable for work involving agents of moderate potential hazard to personnel and the environment. Required practices are BSL-1 practices plus limited access, biohazard warning signs, sharps precautions, and a biosafety manual defining any needed waste decontamination or medical surveillance policies. 

The operation has been completely automated to eliminate hazards to personnel. The implementation of automatic operation is described in the final EDP (AEA, 2001a). 

BSL 2 Biosafety Level 2 is suitable for work involving microorganisms of moderate potential hazard to personnel and the environment. Safety equipment Class I or II biosafety cabinets or other physical containment devices laboratory coats, gloves, face protection as needed. Microorganisms include hepatitis B virus, HIV, salmonellae, and mycoplasma. 

Restrict access" is used only for those chemicals that are unusually and immediately hazardous to personnel unless they are protected properly by respirators, eye goggles, protective clothing, etc. This type of cautionary response is sometimes used in a broader sense to ensure exclusion of spectators and others who might ignite flammable compounds. 

It is therefore considered necessary to provide first-aid fire appliances to deal with the incipient fires which if allowed to grow unchecked, might pose hazard to personnel, plant and property. Adequate water supply is essential for fire fighting and the protection of explosives from attack by fire. 

Design concepts were used to minimize hazards to personnel, to prevent corrosion, and to protect the environment. Special operating procedures, personnel safety equipment, and training completed these design concepts. An extensive ambient-air monitoring network was established to insure that ambient-air standards were met to protect the environment. 

Work surfaces may be wetted with a fine spray to prevent creation of dust. Dusty materials being conveyed may also be sprayed. This practice not only minimizes the problem of airborne dust, but simultaneously reduces product loss. Spray heads may be located at as many locations as have dust problems because the equipment required is moderate in cost and there is no hazard to personnel from Aerosol GPG Surfactant. 

A recovery technique is described for the location and retrieval of items of ammo being proof-tested in the field. Impetus for this work was prompted by the extreme difficulty often encountered in the recovery of small items during firing tests over rugged or difficult terrain. A reliable and rapid location system is often needed to a) recover or destroy live duds to eliminate expl hazards to personnel b) recover... 

The above case study warns that hydrates can be hazardous to personnel and to equipment. Yet hydrate plugs can be safely dissociated with the use of CSMPlug and User s Manual on the CD in the endpapers of this book, with the User s Guide Examples in Appendix B. The safety option of this program and process should be considered first, so that the potential for overpressurization and eruption can be considered. 

It should be possible to easily isolate fluids in equipment and piping when potentially dangerous situations occur. This can be done using emergency block valves (EBVs). An EBV is a manually or remotely actuated protective device that should be used to provide manual or remote shutoff of uncontrolled gas or liquid flow releases. EBVs can be used to isolate a vessel or other equipment, or an entire unit operation. Manual valves are often used on piping at block limits where it is unlikely that there would be a hazard to personnel if an accident occurs. Remotely controlled EBVs are recommended on tanks and on piping in areas where it may be hazardous for personnel in the case of an accident, or where a quick response may be necessary. 

MSDS Material safety data sheet. Printed material on hazardous chemical substances and/or extremely hazardous substances. An MSDS provides information on physical properties, hazards to personnel, fire and explosion potential, safe handling recommendations, health effects, fire-fighting techniques, reactivity, and proper disposal. It was originally established for employee safety by OSHA... 

Install start/stop switches at each door location in the outer shell to allow depressurization of the annulus prior to opening the door-The usual internal pressure on a chimney man door approximates a gale force wind, potentially hazardous to personnel entering and exiting. Switches on both the inside and outside of doors will allow the pressurization system to continue operation while personnel are in the annulus, an important feature for ventilation purposes during extended maintenance work. 

---