Hazardous condition

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. ... 

Of these, the failure logic can easily be the most demanding. The simplest approach is to stop or hold on any abnormal condition, and let the process operator sort things out. However, this is not always acceptable. Some failures lead to hazardous conditions that require immediate action waiting for the operator to decide what to do is not acceptable. The appropriate response to such situations is best determined in conjunc tion with the process hazards analysis. 

Where hazardous conditions can develop within a process, a protective system of some type must be provided. Sometimes these are in the form of process hardware such as pressure rehef devices. However, sometimes logic must be provided for the specific purpose of taking the process to a state where the hazardous condition cannot exist. The term safety interlock. system is normally used to designate such logic. 

Attenuation Another alternative to intensification is attenuation, using a hazardous material under the least hazardous conditions. Thus large quantities of liquefied chlorine, ammonia, and petroleum gas can be stored as refrigerated liquids at atmospheric pressure instead of storing them under pressure at ambient temperature. (Leaks from the refrigeration eqmpment should also be considered, so there is probably no net gain in refrigerating quantities less than a few hundred tons.) Dyestuffs which form explosive dusts can be handled as slurries. 

Fire or explosion hazards require special motor enclosures. Hazards include combustible gases and vapors such as gasoline dust such as coal, flour, or metals that can explode when suspended in air and fibers such as textile lint. The land of motor enclosure used depends on the type of hazard, the type and size of motor, and the probability of a hazardous condition occurring. Some available enclosures are explosionproof motors, which can withstand an internal explosion force-ventilated motors cooled with air from a safe location and totallv enclosed motors cooled bv air-to-water heat exchangers and pressurized with safe air, instrument air, or inert gas,... 

Inadvertent contact between two or more chemicals may lead to a hazardous condition. 

Chemical/materials that may potentially come in contact are incompatible. Inadvertent contact between two or more chemicals may lead to a hazardous condition. 

Close proximity of hazardous processes may result in releases or other hazardous conditions in one process affecting the neighboring process areas, thereby resulting in escalation of the hazard. 

Examining a candidate toller s records of formal reporting and follow-up on mechanical deficiencies or hazardous conditions is imperative. The assessor should verify whether such a system is in place and is effective. 

Has the facility established an effective critical-equipment maintenance program (also termed mechanical integrity program) to prevent failures that would cause hazardous conditions ... 

Are all substandard or hazardous conditions reported m writing and acted upon immediately ... 

Aeration of liquids not only increases charging due to the large liquid-bubble interfacial area but can also produce hazardous conditions in downstream... 

The purpose of the facilities described in this chapter is to provide for safe handling of various drainage materials and emergency streams, so that they may be safely routed to the sewer, tankage, flare, or other appropriate destination. Drainage systems specified herein ensure that flammable or toxic materials may be disposed of without hazard of fire or injury when equipment is taken out of service. Also described are systems to handle process water drawoffs, cooling water, and other aqueous effluent streams which may be contaminated with hydrocarbons, and which could otherwise create hazardous conditions if they were discharged directly to the sewer. 

Protection layers for a typical process are shown in the order of activation expected as a hazardous condition is approached. 

Moderate Use less hazardous conditions, a less hazardous form of a material, or facilities which minimize the impact of a release of hazardous material or energy (also called Attenuation and Limitation of Effects). 

Moderate means using materials under less hazardous conditions, also called attenuation. Moderation of conditions can be accomplished by strategies which are either physical (lower temperatures, dilution) or chemical (development of a reaction chemistry which operates at less severe conditions). 

Moderate Use less hazardous conditions Reduce wastes ... 

Let s look at another example a small-scale voluntary cleanup that might take place in the lot behind a factory, or a tank being removed at a corner gas station. Although we have the same considerations, these projects are on a smaller scale and will create less of a hazardous condition. The same principles that exist at the large job still should be adhered to on the small job. The work zone should be delineated and controlled to protect workers or the public from entering the work zone. For the small job, caution tape, snow fence, or traffic cones can be used effectively. 

Do tagout devices warn against hazardous conditions if the machine or equipment is restarted or energized Do they contain a legend such as Do not start, etc [OSHA Reference, 147(c)(5)(iii)]... 

It generally is recommended, and often required, that gas dcicciiuii systems be installed in a fail-safe manner. That is, if power is disconnected or otherwise interrupted, alarm and/or process equipment shutdown (or other corrective action) should occur. All specific systems should be carefully reviewed, however, to ensure that non-anticipated equipment shutdowns would not result in a more hazardous condition tlian the lack of shutdown of the equipment. If a more hazardous situation would occur with shutdown, only a warning should be provided. As an example, a more hazardous situation might occur if blowout preventers were automatically actuated during drilling operations upon detection of low levels of gas concentrations than if drilling personnel were only warned. 

Checks of critical process parameters and warnings about hazardous conditions that can cause injury or equipment damage are important factors which determine the occurrence and recovery of human error. The purpose of these checks is to emphasize critical process information. Because of the critical nature of this information, checks and warning should be highlighted in a way that distinguishes them from other notes, and should be located where process workers will not overlook them. 

FPN No. 2) Piping without valves, checks, meters, and similar devices would not ordinarily introduce a hazardous condition even though used for flammable liquids or gases. Locations used for the storage of flammable liquids or of liquefied or compressed gases in sealed containers would not normally be considered hazardous unless also subject to other hazardous conditions. 

In all, the board submitted 32 recommendations as a result of its investigation. They include additional training for personnel in nitration and purification areas to enable them to cope with such emergency situations. The board also recommended the development of sensing equipment to uncover possible hazardous conditions earlier in the TNT manufacturing process . 

The most common spill on a laboratory floor is water, not generally considered hazardous. It may, however, create hazardous conditions by making the floor slippery. It is dangerous to walk on a wet floor with certain types of soles. A wet area should always be blocked off until it is dry. Mop and bucket should always be available close by, not in a janitor s closet down the hall. String mops are superior to sponge mops for getting the floor dry. 

It must be possible to reach a safety shower within ten seconds from any area where hazardous conditions exist. 

If laboratory personnel are expected to perform repairs and maintenance, the proper tools must be available. This is particularly true in an educational laboratory, where stockroom personnel have a multitude of repair and maintenance jobs to perform. Only the highest quality tools should be purchased, as they will cost less in the long run. A cheap screwdriver, for instance, will soon begin to wear and damage screws that are hard to replace. It may even slip and cause injury. An almost right wrench will damage nuts beyond use. A cheap wire cutter may leave a few strands of wire uncut, an annoying and possibly hazardous condition. 

In a clean troposphere, ozone would react with NO molecules, resulting in no net generation of ozone. However, in a dirty atmosphere, excess ozone is generated, thereby resulting in the formation of an oxidant which can lead to health effects, an especially hazardous condition for children and the elders who suffer from asthma and other respiratory challenges. 

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