Hazards evaluation factors

To design general area gas detection, each area should be evaluated based on its volume for credible gas release hazards. The factors to consider when determining credible hazards are ... 

Ito et al. (1995) examined the combined dietary administration to rats of 19 organophosphate pesticides and 1 organochlorine pesticide, aU permitted for use in Japan, each at its ADI level. The dietary exposure at this level did not enhance the development of diethyl nitrosamine initiated pre-neoplastic lesions whereas at 100 times the ADI, the number and area of lesions were increased. The authors concluded that the study provided direct support for the present use of the safety factor approach in the quantitative hazard evaluation of pesticides. 

R. Siwek, Determination of technical safety indices and factors influencing hazard evaluation of dusts, ]. Loss. Prev. Process. Indust., 9(1) 21-31,1996. 

Exposure to combinations of chemicals does not always necessarily produce clearly distinguishable interactions. Each situation must be considered in detail with due regard to all the factors that are required to be analyzed in the process of hazard evaluation (59,60). 

The hazard evaluation program requires the expertise of a number of different disciplines as well as the coordination and reconciliation of the project schedule with factors such as equipment suitability, personnel, training and effluent considerations. Obviously, to take into account all of the difficulties associated with starting and running an unfamiliar process in addition to examining the potential hazards of the process is a complicated task. The format described here will work for most manufacturing operations. 

The qnantity of gas or vapor in a container is a function of (in descending order of importance) the container volnme, inclnding the connected piping and other nonisolated equipment, the pressure, the molecular weight of the gas or vapor, the temperature, and the compressibility factor for the gas or vapor. The following eqnation can be used with sufficient accuracy for hazards evaluations ... 

C. Antenna. The antenna is used to make a transition from a guided wave (from the transmission line) to a radiated electromagnetic wave. The design of the antenna is influenced by many factors such as size, frequency, and electrical impedance. Antennas are normally of two types - omnidirectional and directional. The omnidirectional antennas are element type antennas such as monopoles or dipoles. The directional are horn-type antennas, parabolic dish type antennas such as a satellite communications antenna (SATCOM), or a phased-array antenna which can emit many beams at once. The characteristics of the antenna are a very important aspect of hazard evaluation. 

The CDFA, in its hazard evaluation process, determines whether an adequate hazard assessment can be made immediately, or if additional data are needed, based on the consideration of the following factors ... 

A more careful comparison has also been made. JAXA (the Japanese Space Agency) and MIT engineers compared the use of STPA on a JAXA unmanned spacecraft (HTV) to transfer cargo to the International Space Station (ISS). Because human life is potentially involved (one hazard is collision with the International Space Station), rigorous NASA hazard analysis standards using fault trees and other analyses had been employed and reviewed by NASA. In an STPA analysis of the HTV used in an evaluation of the new technique for potential use at JAXA, all of the hazard causal factors identified by the fault tree analysis were identified also by STPA [88]. As with the BMDS comparison, additional causal factors were identified by STPA alone. These additional causal factors again involved those related to more sophisticated types of errors beyond simple component failures and those related to software and human errors. 

Organizations can use a variety of processes to analyze workplace hazards and accident causal factors. Hazard evaluations and accident trend analysis can help improve the effectiveness of established hazard controls. Routine analysis enables an organization to develop and implement appropriate controls for hazardous processes or unsafe operations. Analysis processes rely on information collected from hazard surveys, inspections, hazard reports, and accident investigations. This analysis process can provide a snapshot of hazard information. Effective analysis can then take the snapshots and create viable pictures of hazards and accident causal factors. 

There is no getting around these system laws they will happen, and they will shape the hazard risk presented by a system design. System safety must evaluate the potential impact of each of these system laws and determine if hazards will result, and if so, how the hazards can be eliminated or controlled to prevent mishaps. In other words, these system laws are hazard-shaping factors that must be dealt with during product/process/system design in order to develop a safe system. Since hazards are unique for each system design, safety compliance measures do not provide adequate safety coverage system hazard analysis is thus necessary. 

The SHA is an analysis methodology for identifying hazards, evaluating risk and safety compliance at the system level, with a focus on interfaces and SCFs. The SHA ensures that identified hazards are understood at the system level, that aU causal factors are identified and mitigated, and that the overall system risk is known and accepted. SHA also provides a mechanism for identifying previously unforeseen interface hazards and evaluating causal factors in greater depth. 

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