Design, process safety substitution

A primary objective of any safety program is to maintain or reduce the level of risk in the process. The design basis, especially inherently safer features that are built into the installation, must be documented. Management of change programs must preserve and keep the base record current and protect against elimination of inherently safer features. For identical substitution, the level of risk in the process is... 

The same individuals should attend all safety review meetings for a particular facility. Substitution of other individuals for a designated position during a review impairs the continuity and quality of the review. Should a convenient process or facility review break occur during the study, which does not impact continuity, a replacement individual may be considered. This is especially important if further staff training or experience in the review cycle is helpful. 

The plausible universe of alternatives to decaBDE for achieving fire safety in TV enclosures includes chemical substitutes, inherently flame resistant materials that eliminate the need for added flame retardant chemicals (for example, steel or aluminum), and TV re-design options that eliminate the need for flame retardants by separating the enclosure from the heat source. Alternative enclosure designs that eliminate the need for added chemical flame retardants and meet or exceed performance specifications (including flame retardancy) are considered inherently preferable alternatives, particularly if they are derived from benign chemicals (and safe processes) and are recyclable or compostable at end of life. 

National Highways Traffic Safety Administration (NHTSA) reported an interesting study (NHTSA, 2012) on material substitution from steel to polymer composite in the 2007 Chevrolet Silverado FE model. The substitution resulted in a 19% decrease in vehicle weight (from 2307 to 1874kg) with no effect on safety in front crash tests. However, replacing metal components with composite or plastic is not a trivial process it requires the redesign of the vehicle and therefore demands upfront capital investment as well as design time. 

In order to compensate for these variations in operating conditions, the designer uses a capacity safety factor to increase the calculated condensate load. This safety factor should be selected with care. One short-cut method that should be avoided sizing steam traps to equal line size. This practice is never a substitute for analyzing process conditions it invariably leads to specification of the wrong size steam trap. 

An effective procurement process to ensure that the proper parts, materials, and services are available when needed must be in place for restart. Policies should be established for the procurement of parts, materials, and services that are used in maintenance activities on important-to-safety and safety-related systems. Quality assurance procurement records need to be controlled and maintained to provide documentation for qualified parts and materials and ensure traceability of parts and materials. Deficient or nonconforming items should be resolved in an effective and timely manner. A process should be provided to qualify non-qualified material, A process of acceptable substitution should be provided to obtain parts that are no longer available. Design requirements should be reviewed by appropriate personnel to ensure the upgraded or substitute parts are consistent with the application of the part and component. Retrievable documentation should exist to support the identification of inspection and testing requirements necessary to ensure the qualification and acceptability of the part. Personnel must understand their responsibilities in regard to the implementation of the requirements of the procurement program and policies. 

The six items above have been selected for use because of their sinqilicity and because they are common to every safety program. Any of them can be substituted, if the organization wants other program elements used instead. Only six elements are being used here because the process must be effective, yet simple in design. 

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