Preliminary hazard analysis , risk

Key phrases systematic search for hazards, preliminary hazard analysis, risk reduction decisions. 

To those already familiar with hazard/risk analysis methods, a "PHA" designates a Preliminary Hazard Analysis. Unfortunately, the PSM Rule uses these same letters to designate Process Hazard Analysis. In this document, PrHA will designate Process Hazard Analysis to avoid confusion with Preliminary Hazard Analysis. Note that other literature may be confusing on this issue. 

A designer, as part of his facility design analysis, should perform a hazards analysis or risk assessment of the various processes which will be conducted within the facility in order to determine what potential thermal dangers or threats exist to personnel and equipment. A hazards analysis or risk assessment will provide for the identification of potential hazards and of the necessary corrective actions/measures to prevent or control the hazard. Early in the design of a facility, the processes and equipment may be conceptual and at this stage, a preliminary hazards analysis can be performed. It is early in the design that a preliminary hazards analysis can be most helpful because its... 

Preliminary Hazard Analysis Description. The incorporation of this information into a PHA entry is shown as Table II. This entry describes the proposed actions needed to eliminate or control the hazard (column 6), the risk assessment code assigned after controls (column 7), and the identification of applicable codes and standards (column 8). 

Several qualitative approaches can be used to identify hazardous reaction scenarios, including process hazard analysis, checklists, chemical interaction matrices, and an experience-based review. CCPS (1995a p. 176) describes nine hazard evaluation procedures that can be used to identify hazardous reaction scenarios-checklists, Dow fire and explosion indices, preliminary hazard analysis, what-if analysis, failure modes and effects analysis (FMEA), HAZOP study, fault tree analysis, human error analysis, and quantitative risk analysis. 

For example, the hazard analysis and risk assessment requirements of the European Standard ISO 14121, Safety of Machinery—Principles for risk assessment (formerly EN 1050), have been adequately met in some companies in the design or redesign stages by applying an adaptation of the preliminary hazard analysis technique. 

A communication accompanies the analysis, explaining the assumptions made and the rationale for them. Comment would be made on the assignment of responsibilities for the remedial actions to be taken, and when. An example of a preliminary hazard analysis worksheet appears as Addendum A in this chapter, courtesy of Sverdrup Technologies, Inc. This form requires entry of severity, probability, and risks codes before and after countermeasures are taken. 

Many hazard analysis and risk assessment techniques have been developed. These are just a few of the methodologies mentioned in the literature preliminary hazard analysis gross hazard analysis hazard criticality ranking catastrophe analysis change analysis energy flow/barrier analysis energy transfer analysis event tree analysis human factors review the hazard totem pole and double failure analysis. There are many other hazard analysis systems. 

System safety is hazards-focused, as are all the subsets of the practice of safety, whatever they are called. System safety commences with hazard identification and analysis. Do that poorly, and all that follows is misdirected. Applications of the hazard analysis and risk assessment methods developed in the evolution of system safety have been successful. The generalist in safety practice ought to know more about them. As a minimum, generalist safety practitioners should be knowledgeable about these methods Preliminary Hazard Analysis What-If Analysis and Failure Modes and Effects Analysis. (See Chapter 14, Hazard Analysis and Risk Assessment. )... 

A Brief Overview of Selected System Safety Analytical Approaches Working with the Risk Assessment Matrix Preliminary Hazard Analysis Energy Flow/Barrier Analysis Failure Modes and Effects Analysis Fault Tree Analysis... 

The DECRIS RVA has two phases Phase 1 consists of a risk screening of undesired events, and is similar to a preliminary hazard analysis (PHA). Phase 2 consists of the following steps ... 

The preliminary hazard analysis (PHA) expands the preliminary hazard list by identifying additional hazards, analyzing identified hazards, recommending hazard controls, and determining the level of risk after the controls are... 

Medium-risk facilities normally require at least a preliminary hazard analysis and some user involvement. 

In an effort to demonstrate the utDity of the preliminary hazard list and the preliminary hazard analysis in the initial evaluation of system risk, an example of a simple vapor degreaser in a manufacturing facility will be examined. This illustration will utilize the PHL in the development of the PHA in the method discussed earlier in this chapter. However, it must be noted from the outset that this example is intended... 

Preliminary hazard analysis is one of the early steps in a system safety project. This step also creates assessments of risks associated with each hazard. This step defines possible corrections for the risks. The product of this step is a tabular inventory of hazards for the system under consideration. The PHA fits best during early system stages, such as concept definition, design, and development. 

During the concept phase, historical data and technical forecasts are developed as a base for a system hazard analysis. A Preliminary Hazard Analysis (PHA) is conducted during this phase. At the gross level, a Risk Analysis (RA) is performed to ascertain the need for hazard control and to develop system-safety criteria. Safety management will be doing the initial work on the System Safety Program Plan (SSPP). Three basic questions must be answered by the time the concept phase is completed ... 

PRELIMINARY HAZARD ANALYSIS HAZARD ANALYSIS AND RISK ASSESSMENT... 

The original use of the preliminary hazards analysis (PHA) technique was to identify and evaluate hazards in the early stages of the design process. However, in actual practice the technique has attained much broader use. The principles on which preliminary hazards analyses are based are used not only in the initial design process, but also in assessing the risks of existing products or operations. 

Definition of hazard, risk discussions on likelihood, consequence risk — register, matrix, ranking. Consequence ranking, preliminary hazard analysis tolerance point—ALARP refreshing on mathematics, fault tolerance, plant ageing, and basic functional safety fail safe operations in plants. 

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