Process safety check lists

A short safety check list, covering the main items which should be considered in process design, is given below. 

Safety check lists can provide a uselul guide for the main items to be considered during the process design stage. It must be remembered that no list is ever complete and other considerations and techniques should also be applied. Safety check lists can be found in Coulson and Richardson, Volume 6 (1983 pp. 301-303) IChemE Flowsheeting for Safety (1976) Wells (1980) and Balemans (1974). 

Balemans, A. W. M. (1974) Check-lists guide lines for safe design of process plants. Loss Prevention and Safety Promotion in the Process Industries, C. H. Bushmann (ed.) (Elsevier). 

The approach used to identify hazards will depend on the application being considered. For certain simple processes where there is extensive operating experience of a standard design, such as simple off-shore wellhead towers, it may be sufficient to use industry developed check lists (for example, the safety analysis checklists in ISO 10418 and API RP 14C). Where the design is more complex or a new process is being considered, a more structured approach may be necessary (for example, lEC 60300-3-9 1995). 

PSSR (conducted before the modifications are commissioned) is also a part of the MOC procedure. Any new items identified during the PSSR may require further rounds of review and approvals by the reviewers. Completed MOC is an important part of process safety management it needs to be filed in the facility s process safety and project files, and stored for the lifetime of plant operations. These forms are required for future MOC audit and also are useful during future PHA studies. CCPS (1995) and CCPS (2007) presented MOC process and useful check lists. Note that a proper MOC procedure could have avoided the Flixborough incident outlined in Section 3.2 (CCPS, 2007). 

Check lists serve to draw one s attention to safety relevant issues. They reflect to a large extent the experiences with the design, building and operation of plants and the corresponding safety analyses. Apart from the normal operation the lists should cover start-up and shut-down as well as other possible plant states. In what follows a checklist for process plants is presented. Further information can be found in the relevant literature, for example also in [9]. 

CONTROL OF PROCESS AND PLANT MODIFICATIONS Uncontrolled modifications to a process or plant can result in a situation that was not considered in the original hazard assessment and the existing safety measures may no longer be effective. It is not possible to produce a generally applicable check-list of significant" modifications — serious incidents have been caused by relatively small changes in process conditions or plant construction — but some examples are ... 

Any good quality-assurance system should also assess the quality of performance in practice as well as in theory. With no currently available, effective, non-destructive test, critical areas or components may only be assessed for voids (acoustic methods are useful here) and, where possible, proof loaded. Other than this, test coupons or parts need to accompany the components themselves through the assembly process so that appropriate, systematic destructive tests may be carried out. A check-list for safety critical items is given in Table 6.1. 

There are many hazard analysis formulations which may be used effectively to assess process hazards. These include fault-free analysis, failure mode and effect analysis (FMEA), what-if analysis, hazard and operability analysis (HAZOP), check list analysis, and safety review, among others. The specifics associated with these analyses can be reviewed by consulting the appropriate American Institute of Chemical Engineers Center for Chemical Process Safety reference. " ... 

It should be emphasized that the procedures which are being made available are unedited and have been reproduced just as they were first received from the submitters. There is no assurance that the procedures listed here will ultimately check in the form available, and some of them may be rejected for publication in Organic Syntheses during or after the checking process. For this reason, Organic Syntheses can provide no assurance whatsoever that the procedures will work as described and offers no comment as to what safety hazards may be involved. Consequently, more than usual caution should be employed in following the directions in the procedures. 

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