Hazardous conditions, anticipating

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. 

HOWEVER, ISA ASKS THAT ANYONE REVIEWING THIS STANDARD WHO IS AWARE OF ANY PATENTS THAT MAY IMPACT IMPLEMENTATION OF THE STANDARD NOTIFY THE ISA STANDARDS AND PRACTICES DEPARTMENT OF THE PATENT AND ITS OWNER. ADDITIONALLY, THE USE OF THIS STANDARD MAY INVOLVE HAZARDOUS MATERIALS, OPERATIONS OR EQUIPMENT. THE STANDARD CANNOT ANTICIPATE ALL POSSIBLE APPLICATIONS OR ADDRESS ALL POSSIBLE SAFETY ISSUES ASSOCIATED WITH USE IN -HAZARDOUS CONDITIONS. THE USER OF THIS STANDARD MUST EXERCISE SOUND PROFESSIONAL JUDGMENT CONCERNING ITS USE AND APPLICABILITY UNDER THE USER S PARTICULAR CIRCUMSTANCES. THE USER MUST ALSO CONSIDER THE APPLICABILITY OF... 

Anticipate, identify and evaluate hazardous conditions and practices. 

A. Anticipate, identify, and evaluate hazardous conditions and practices. This function involves 1. Developing methods for... 

At many active workplaces, daily site inspections are performed by the supervisor in order to detect hazardous conditions, equipment, materials, or unsafe work practices. At other times, periodic site inspections are conducted by the site safety and health officer. The frequency of inspections is established in the workplace safety and health program. The supervisor, in conjunction with the safety and health officer, determines the required frequency of these inspections, based on the level and complexity of the anticipated activities and on the hazards associated with these activities. In a review of worksite conditions/activities, site hazards, and protecting site workers, the inspections should include an evaluation of the effectiveness of the company s safety and health program. The safety and health officer should revise the company s safety and health program as necessary to ensure the program s continued effectiveness. 

The Scope and Functions of the Professional Safety Position issued by the American Society of Safety Engineers (1998) says that the s ety professional is to anticipate, identify, and evaluate hazardous conditions and practices and develop hazard control designs, methods, procedures, and programs. Those are valid statements. 

Daily inspections of excavations, the adjacent areas, and protective systems shall be made by an authorized person for evidence of a situation that could result in possible cave-ins, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions. An inspection shall be conducted by this person prior to the start of work and as needed throughout the shift. Inspections shall also be made after every rainstorm or other hazard-increasing occurrence. These inspections are only required when employee exposure can be reasonably anticipated. 

Prior to an anticipated air release of a hazardous material, a circular evacuation strategy may be appropriate. Evacuation might also be initiated for a keyhole-shaped area baised on prevailing wind conditions. These strategies are illustrated below. When a large number of people aie involved, the evacuation should be staged, that is, arc ls closest to the site should be evacuated first and the evacuation zone gradually expanded. 

In the application of the multienergy concept, a particular vapor cloud explosion hazard is not determined primarily by the fuel-air mixture itself but rather by the environment into which it disperses. The environment constitutes the boundary conditions for the combustion process. If a release of fuel is anticipated somewhere, the explosion hazard assessment can be limited to an investigation of the environment s potential for generating blast. 

The procedure for specifying the location of reliefs requires the review of every unit operation in the process and of every process operating step. The engineer must anticipate the potential problems that may result in increased pressures. Pressure relief devices are installed at every point identified as potentially hazardous, that is, at points where upset conditions create pressures that may exceed the MAWP. 

Detonation arresters are typically used in conjunction with other measures to decrease the risk of flame propagation. For example, in vapor control systems the vapor is often enriched, diluted, or inerted, with appropriate instrumentation and control [5]. In cases where ignition sources are present or predictable (such as most vapor destruct systems), the detonation arrester is used as a last-resort method anticipating possible failure of vapor composition control. Where vent collection systems have several vapor/oxidant sources, stream compositions can be highly variable and this can be additionally complicated when upset conditions are considered. It is often cost-effective to perform hazard analyses such as HAZOP or fault... 

The purchaser will specify the equipment s normal and rated operating points. The purchaser will also specify any other anticipated operating conditions. The purchaser will specify when fluids are flammable or hazardous. 

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