System safety 598 INDEX

The fitness function was based on the inherent safety index, which was simplified It was noticed that there are only minor differences in the safety properties of the compounds in the process. Therefore most subindices are the same for all configurations. The equipment type used in all the configurations is the same (i.e. distillation). Therefore the subindex of equipment safety is constant too. Also the safety of process structures is quite the same since the distillation systems used are rather similar in configuration. Therefore the subindex for process structure was not evaluated and case-based reasoning was not needed. 

In the past, several terms have been coined to describe the retention efficiency of the filter system beta value, microbiological safety index, reduction ratio, and titer reduction ratio [64,68,72], The log reduction value (LRV) is a filter retention efficiency term that is the logarithm to the base of 10 of the ratio of the number of organisms in the challenge suspension to the number of organisms in the filtrate. 

Until now research efforts in safety management have been focussing primarily on the number of accidents (system failures leading to personal injuries andlor material damages) as the prime index for system safety. There are three main reasons for redirecting our attention in this respect ... 

Toxicological evaluation of identified and unidentified impurities from a container can help improve the safety index of drug products. The toxicological evaluation should take into consideration container closure system properties, drug product formulation, dosage form, route of administration, and dose regimen. A close correlation between chemical and toxicological information can provide better control on safety and compatibility of containers and closures. 

Once fully verified the up-to-date and fnlly populated fault trees should then be written up either as an annex of the System Safety Assessment or as a separate report. The annex or report should include an index of the failure conditions considered, including the probability targets which were set. For eaeh fault tree, include the following ... 

Ai Lin Teo and Yean Yng Ling (2006) developed a method that can be used to assess the effectiveness of a construction firm s safety management system. The Construction Safety Index (SCI) can also be calculated by using this model. 

DIDs are documents describing the content and format for specific types of data required by contract in the CDRL. The contractor prepares the required data in a format specified in a DID. Preexisting DIDs are indexed in the Acquisition Management System Data List (AMSDL). The following preexisting DIDs are associated with system safety ... 

The DAL is an index number ranking the safety-criticality of the system functions. This ranking implies that in order to make the system safe, greater development rigor must be applied to each successively critical level. Table 2.3 correlates the hardware DALs to the five classes of failure conditions and provides definitions of hardware failure conditions and their respective DALs. Initially, the hardware DAL for each hardware function is determined by the SSA process using a functional hazard analysis (FHA) to identify potential hazards and then the preliminary system safety assessment (PSSA) process allocates the safety requirements and associated failure conditions to the function implemented in the hardware. 

The Hazard Risk Index (HRI) matrix is a risk management tool used by system safety for hazard/mishap risk assessment. The HRI matrix establishes the relative level of potential mishap risk presented by an individual hazard. By comparing the calculated qualitative severity and likelihood values for a hazard against the predefined criteria in the HRI matrix, a level of risk is... 

Elame-spread and smoke-density values, and the less often reported fuel-contributed semiquantitive results of the ASTM E84 test and the limited oxygen index (LOI) laboratory test, are more often used to compare fire performance of ceUular plastics. AH building codes requite that ceUular plastics be protected by inner or outer sheathings or be housed in systems aH with a specified minimum total fire resistance. Absolute incombustibHity cannot be attained in practice and often is not requited. The system approach to protecting the more combustible materials affords adequate safety in the buildings by aHowing the occupant sufficient time to evacuate before combustion of the protected ceUular plastic. 

TSCATS is an online index to unpublished, nonconfidential studies covering chemical testing results and adverse effects of chemicals on health and ecological systems. The studies are submitted by US industry to EPA under several sections of the Toxic Substance Control Act (TSCA). There are four types of documents in the database Section 4 chemical testing results, Section 8(d) health and safety studies, Section 8(e) substantial risk of injury to health or the environment notices, and voluntary documents submitted to EPA known as a For Your Information (FYI) notice. 

Hazards surveys This can be as simple as an inventory of hazardous materials, or it can be as detailed as the Dow indexes. The Dow indexes are a formal rating system, much like an income tax form, that provide penalties for hazards and credits for safety equipment and procedures. 

The procedure begins with a material factor that is a function only of the type of chemical or chemicals used. This factor is adjusted for general and special process hazards. These adjustments or penalties are based on conditions such as storage above the flash or boiling point, endo- or exothermic reactions, and fired heaters. Credits for various safety systems and procedures are used for estimating the consequences of the hazard, after the fire and explosion index has been determined. 

The damage radius is first estimated using a correlation published in the complete Dow index. This correlation is based on the previously determined F EI. The dollar value of the equipment within this radius is determined. Next, a damage factor (based on a correlation provided) is applied to the fraction of the equipment actually damaged by the explosion or fire. Finally, a credit factor is applied based on safety systems. The final number, in dollars, is the MPPD value. This number is used to estimate the MPDO using a correlation. Details on the procedure are available in the complete Dow reference. 

The intrinsic safety is however affected by both the process equipment and the properties of the chemical substances present in the process. Therefore also the index should reflect this fact. We have included parameters into the list (Table 5) to represent the process aspects of the inherent safety. These parameters are the type of equipment involved and the safety of process structure which describe the process configuration from a system point of view. Also a third parameter to describe the interaction (reactivity) of the chemicals present in the process has been included, since this is an obvious source of risk. 

In order to reflect these lead times, the concept of a timestamp is introduced. Timestamp is used in computer science documenting the system time when a certain event or transaction occurs e.g. for logging events (N.N. 2007). In the context of future inventory value planning, the time-stamp marks the period, when the first raw material has reached a certain stage in the value chain network included into a specific product. In the example illustrated in fig. 57, the raw material is processed in the same period to be converted into product 1. Therefore, all four value chain steps indexed from one to four occur in the same period and have the same time-stamp one. Conversion into product 2, however, requires additional time caused by production lead times, safety inventory and/or transportation time, that the steps indexed with five and six have a time stamp of two. The timestamp reflects that the inventory value of product 2 is not based on the raw material costs from the same period but based on the raw material costs from the previous period in order to reflect the lead time. Consequently, value chain indices and timestamps are defined for all steps and can cover multiple periods reflecting that raw materials in a global complex multi-stage value chain network can take several months, until they are sold as part of a finished product to the market. 

Toxicity studies should be designed not only to identify a safe dose, but also a toxic dose(s) to anticipate the product s safety and to better define the therapeutic index in humans. Specific product considerations that may complicate the process of defining a toxic dose may include limits based on formulation, lack of significant systemic absorption, or the amount of the product available. The lack of significant toxicity in animals does not necessarily mean that the product is safe. The margin of safety for the initial starting dose, however, will likely be adequate. 

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