Process examination, hazard review

During process hazards reviews (such as HAZOP), inherent safety concepts are also considered. Mistake proofing the design should receive attention and each safety critical device (last line of defense) and safety critical procedure should be examined to see if there is a way to eliminate the need for the device or procedure. 

Trevor Kletz is the most published Loss Prevention Engineer of all time with nine process safety books and over 100 technical articles. Professor Kletzs topics in this chapter assume that some of the modern synthetic materials we use daily have been available since the dawn of time and that some ordinary materials are being examined in a sort of hazards review session. These are Kletzs most classic, clever illustrations of how we can sometimes be overzealous and too narrow in our focus on a problem. 

Reactive hazard evaluations should be made on all new processes as well as existing processes on a periodic basis. There is no substitute for experience, good judgement, and good data when evaluating potential hazards. Reviews in process chemistry should include (a) reactions, (b) side reactions, (c) heat of reaction, (d) potential pressure buildup, and (e) intermediate streams. Reactive chemicals test data should be reviewed for evidence of flammability characteristics, exotherms, shock sensitivity, or other evidence of instability. Examine Planned operation of the process should be examined, especially for... 

Process Hazards Reviews comprise formal committee meetings where hours are spent intensively examining, by one of the methods described later, a chemical reaction or process, with a report, documentation, and follow-up. Pre-Startup Reviews/Process Hazards Audits are no less intensive, but the time spent is less, because the complexity of the process or equipment being examined is less. Reports, documentation, and follow-up are also a part of the Pre-Startup Review/Process Hazards Audit. An equipment acceptance safety inspection would be considered a Process Hazards Audit. 

When a decision is made to pilot a process, the Pilot Plant Director schedules the review sequence and notifies the R D Chemist who provides a process summary to individual members of the Hazard Review Team. The Safety Officer will then examine the process for the presence of possible toxic or irritating compounds while the Environmental Coordinator decides the ultimate fate of any process waste streams. The Hazard Evaluation Chemist identifies any thermal or reactive hazards associated with the process. If a hazard is identified, the Process Engineer determines the suitability of a particular reactor grouping to handle the specific conditions involved. 

Once every member of the Review Team has had a chance to examine the process, the entire Team meets to decide upon the safest operating procedures. From the notes of this meeting, a Hazard Review Summary is prepared. The R D Chemist uses this Summary to prepare a finalized set of manufacturing directions. At this point the process is considered ready for piloting. 

An audit program was implemented that requires an examination of system documentation as part of the cyclic process hazard review. A report is issued describing the results of the audit and any recommendations from the audit are flagged for follow-up (at quarterly intervals) until they are completed. 

Assessment Phase The assessment phase aims to collect data needed to identify and analyze pollution-prevention opportunities. Assessment of the facility s waste-reduction needs includes the examination of hazardous waste streams, process operations, and the identification of techniques that often promise the reduction of waste generation. Information is often derived from obsei vations made during a facihty walk-through, interviews with employees (e.g., operators, line workers), and review of site or regulatory records. One professional organization suggests the following information sources be reviewed, as available (Ref. 7) ... 

Examine the hazardous characteristics of each process chemical. Review the MSDSs, which should have information on the toxicity, flammability, and reactivity of process chemicals and on their incompatibilities with other materials. 

Other possible preliminary safety analysis methods are concept safety review (CSR), critical examination of system safety (CE), concept hazard analysis (CHA), preliminary consequence analysis (PCA) and preliminary hazard analysis (PHA) (Wells et al., 1993). These methods are meant to be carried out from the time of the concept safety review until such time as reasonably firm process flow diagrams or early P I diagrams are available. 

The essence of the ASTM E 2012 approach is to determine incompatibility scenarios that could foreseeably occur by examining all possible binary combinations. It may be necessary to review a process by using a systematic method such as a process hazard analysis (PHA) to identify all incompatibility scenarios that have a significant likelihood of occurrence and severity of consequences. The same review can then be used to evaluate whether adequate safeguards exist or whether further risk reduction is warranted. 

At first glance, this incident does not appear to be process safety related since there was no direct loss of containment however, many factors make it important to review. The material involved in the incident was an undesirable byproduct of an engineered process. AAdien unknown material accumulates in an undesirable location, it often creates a physical hazard. This hazard may directly trigger a loss when it is least expected. Accumulated solids in closed systems may contribute to corrosion, blockage, and physical damage. This accident case study should also be examined in the context of an enclosed system. 

A fundamental objective of a computer system applied to automate a pharmaceutical GMP operation is to ensure the quality attributes of the drug product are upheld throughout the manufacturing process. It is therefore important that quality-critical parameters are determined and approved early in the validation life cycle. The exercise should be undertaken to a written procedure with base information from the master product/production record file examined and quality-critical parameter values and limits documented and approved for the process and its operation. In addition, the process and instrument diagrams (P IDs) should be reviewed to confirm the measurement and control components that have a direct impact on the quality-critical parameters and data. This exercise should be carried out by an assessment team made up of user representatives with detailed knowledge of both the computer system application and process, and with responsibility for product quality, system operational use, maintenance, and project implementation. This exercise may be conducted as part of an initial hazard and operability study (HAZOP) and needs to confirm the quality-related critical parameters for use in (or referenced by) the computer control system URS. 

A completed review report can be used to demonstrate to interested parties that a process hazard analysis has been accomplished and all possible actions have been examined and or implemented to eliminate major hazards. 

Preventive Medicine Activity (MIRADCOM). This operation surveys all processes and procedures for medical safety. They review (and approve in selected instances) standard operating procedures. Laboratories are surveyed for toxic chemical levels. Also, chemical procedures are monitored to determine the level of exposure to toxic substances. They perform annual physical examinations on all personnel involved in hazardous operations or exposed to hazardous chemicals. Medical histories are maintained. Techniques of emergency treatment for both standard and unusual incidents are kept updated. 

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