Hazard analysis safety

Figure 3-9 Use Case Diagram Representing Hazard Analysis Safety Procedure...

General management system characteristics in control of the job, so called G-factors. They include Plant policies, implementation of methods, staff, information flow, management services, budgets, and risk assessment system, such as technical information system, hazard analysis, safety program review etc. 

Contractors projects worth at least S 10 million have to implement a safety management system covering such areas such as hazard analysis, safety policy, in house safety rules, safety inspections, safety work practices, and maintenance of machinery and equipment. 

The purpose of hazard analysis and risk assessment ia the chemical process industry is to (/) characterize the hazards associated with a chemical facihty (2) determine how these hazards can result in an accident, and (J) determine the risk, ie, the probabiUty and the consequence of these hazards. The complete procedure is shown in Figure 1 (see also Industrial hygiene Plant safety). 

For chemical faciUties in the United States, hazard analysis is not an option if inventories of hazardous chemicals are maintained in amounts greater than the threshold quantities specified by the Occupational Safety and Health Administration (OSHA) regulation 1910.119. Many faciUties are finding that hazard analysis has many benefits. The process or procedure often works better, the quaUty of the product is improved, the process experiences less down time, and the employees feel more comfortable in the work environment after a hazard analysis has been completed. 

Methods for performing hazard analysis and risk assessment include safety review, checkhsts, Dow Fire and Explosion Index, what-if analysis, hazard and operabihty analysis (HAZOP), failure modes and effects analysis (FMEA), fault tree analysis, and event tree analysis. Other methods are also available, but those given are used most often. 

Safety Review. The safety review was perhaps the very first hazard analysis procedure developed. The procedure begins by the preparation of a detailed safety review report. The purpose of this report is to provide the relevant safety information regarding the process or operation. This report is generally prepared by the process engineer. A typical outline for this report follows. 

Process Hazards Analysis. Analysis of processes for unrecogni2ed or inadequately controUed ha2ards (see Hazard analysis and risk assessment) is required by OSHA (36). The principal methods of analysis, in an approximate ascending order of intensity, are what-if checklist failure modes and effects ha2ard and operabiHty (HAZOP) and fault-tree analysis. Other complementary methods include human error prediction and cost/benefit analysis. The HAZOP method is the most popular as of 1995 because it can be used to identify ha2ards, pinpoint their causes and consequences, and disclose the need for protective systems. Fault-tree analysis is the method to be used if a quantitative evaluation of operational safety is needed to justify the implementation of process improvements. 

A process hazards analysis is intended to identify the safety interlocks required for a process and to provide the following for each ... 

Diversity is recognized as a useful approach to reduce the number of defects. The team that conducts the process hazards analysis does not implement the safety interlocks but provides the specifications for the safety interlocks to another organization for implementation. This organization reviews the specifications for each safety interlock, seeking clarifications as necessary from the process hazards analysis team and bringing any perceived deficiencies to the attention of the process hazards analysis team. 

Process Hazard Analysis (PHA) (Dowell, 1994, pp. 30-34.) The OSHA rule for Process Safety Management (PSM) of Highly Toxic Hazardous Chemicals, 29 CFR 1910.119, part (e), reqmres an initial PHA and an update every five years for processes that handle listed chemicals or contain over 10,000 lb (4356 kg) of flammable material. The PHA must be done by a team, must include employees such as operators and mechanics, and must have at least one person skilled in the methodology employed. Suggested methodologies from Process Safety Management are listed in Table 26-1. 

TABLE 26-1 Process Hazard Analysis Methods Listed in the OSHA Process Safety Management Rule... 

The book does not focus on occupational safety and health issues, although improved process safety can benefit these areas. Detailed engineering designs are outside the scope of this work. This book intends to identify issues and concerns in batch reaction systems and provide potential solutions to address these concerns. This should be of value to process design engineers, operators, maintenance personnel, as well as members of process hazards analysis teams. While this book offers potential solutions to specific issues/concerns, ultimately the user needs to make the case for the solutions that provide a balance between risk... 

Examining the lists above makes it clear that a good toller-client relationship with open and honest communication of process safety information, process hazard analysis input and early recognition of issues can help avoid potential problems. 

While material safety data sheets (MSDS) provide important information they may not provide information on all hazards that may be encountered during processing. A review of the MSDS is not a substitute for conducting a process hazards analysis. Additional information to consider should include ... 

Working with a Process Hazards Analysis (PHA) team was particularly rewarding. The plant operators on the team pointed out items that they had considered safety problems for years, but that hadn t been fully addressed until the PHA team was formed. We used the What if analysis method. Many methods are available for PHA. 

Deciding among a number of process options having inherent safety advantages and disadvantages with respect to different hazards can be quite difficult. The first step is to understand thoroughly all hazards associated with the process options. Process hazard analysis and evaluation techniques are appropriate tools (CCPS, 1992). These include ... 

The safety status of the process should be periodically reviewed against the guiding principles for the original design. Monitoring of add-ons can detect potentially dangerous modifications. Process hazards analysis or process safety audits are useful tools for this review. Documentation of inherently safer principles is critical to ensure that future changes don t nullify the positive features of the initial installation. 

Bayer (Pilz, 1995) uses a procedure based on hazard analysis, focusing on the application of inherent safety principles to reduce or eliminate hazards. 

In Chapter 4 we will diseuss the regulatory framework and analyti-eal tools to eonduet these assessments, sueh as JHA (job hazard analysis), job safety analysis (JSA), safety analysis reports, proeess hazard analysis (PHA), and job, task, and hazard analysis. The reader needs to understand that OSHAs view on physieal and ehemieal hazards is far reaehing, as stated in the HAZWOPER standard. Note the following examples. 

HAZWOPER applies only where exposure to hazardous substanees or to health and safety hazards resulting from a hazardous waste operation is likely (see Eigure 2-1). This ean be determined by analysis of exposure monitoring data, hazard eharaeterization, hazard analysis, or exposure assessment [1]. Some of the speeifle examples of work aetivi-ties and situations will be eovered later. 

You may have heard other terms sueh as job safety analysis (JSA), aetivity hazard analysis (AHA), or task-speeifie hazards analysis (THA). No matter what you eall the term, a job hazard analysis (JHA) is a proeess that ean used to help develop safe work praetiees or proeedures. 

Included in OSH As JHA Booklet, 3071, is a good description of a process hazard analysis (PHA) [1]. This is being used in the Process Safety Management (PSM) program (29 CER 1910.119) to understand how hazards exist. There are some good methods listed in the manual that can be used to conduct a JHA. As you review each method you can determine which one may be useful for your operation. The typical method chosen is the checklist. 

Detailed guidanee on the eontent and applieation of proeess hazard analysis methodologies is available from the Ameriean Institute of ehemieal Engineers Center for Chemieal Proeess Safety, 345 E. 47th Street, New York, New York 10017, (212) 705-7319. Also, see the diseussion of various methods of proeess hazard analysis eontained in the Appendix to this publieation. 

On July 17, 1990, OSHA issued a proposed rule for the management of hazards assoeiated with proeesses using highly hazardous ehemieals. This rule, ealled the Proeess Safety Management Standard, was finalized on February 24, 1992. In an appendix to the proposed rule, OSHA diseussed several methods of proeess hazard analysis. That diseussion may be helpful for those doing job hazard analyses. Refer to Chapter 4 for these methods. 

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