Physical testing hazard evaluation process

When testing on a particular process is completed, the Hazard Evaluation Chemist prepares a report identifying any reactive problems which were observed. He also reports the actual values of any physical parameters (heat of reaction, decomposition temperature) which were determined and makes recommendations as to what areas (if any) should be addressed by the Process Engineer. 

Thermochemical hazard evaluation should be an integral part of any chemical process hazard review. This paper discusses how a pharmaceutical chemical development group performs thermochemical hazard evaluation through a combination of literature searches and physical testing. It will briefly discuss the physical testing methods and some of the philosophy behind them. 

Our evaluation utilizes a combination of literature searches and physical testing. The literature search is a part of a comprehensive literature search for all types of biological and chemical hazards. It is performed by the chemist in charge of the project before any other work is started, and it is updated to include any changes as the process is developed. The literature sources used in these searches that are of interest for the identification of thermochemical hazards are listed in Table I. The Sandoz Ltd.,... 

There are several points to be kept in mind when using physical testing as part of process hazard evaluation. First, the limitations of the test method should always be kept in mind. For example, it has been pointed out that different thermal stability tests give different exotherm detection temperatures. In most cases it is not possible to define an exact exotherm onset because the decomposition reaction s rate does not go to zero as the temperature is lowered. Overconfidence in test results can be just as much of a hazard as no knowledge at all if the limitations of the tests are forgotten. 

Often misused rules-of-thumb in the evaluation of thermal hazards are the 100 Degree Rule and similar rules which state that, if the operating temperature of a process is 1(X)°C or some other temperature difference lower than the nearest detectable exotherm observed in a small-scale test, then the process operation will not experience this thermal event and it is not necessary to obtain more detailed information from other, more sensitive tests. Several factors govern the temperature dependent rates of heat generation as detected in small-scale tests. These include the physical aspects of the test procedure such as sample size, the Phi factor, sensitivity and agitation, and the thermokinetic aspects of the reaction being studied, in particular the activation energy. ... 

HACCP is a systematic approach to the identihcation, evaluation, and control of food safety hazards. This methodology, which in effect seeks to plan out unsafe practices, differs from traditional produce and test quality assurance methods which are less successful and inappropriate for highly perishable foods. HACCP is used in the food industry to identify potential food safety hazards, so that key actions, known as critical control points (CCPs) can be taken to reduce or eliminate the risk of the hazards being realized. HACCP is a systematic preventative approach to food safety that addresses physical, chemical, and biological hazards as a means of prevention rather than finished product inspection. The system is used at all stages of food production and preparation processes. HACCP is also being applied to industries other than food, such as cosmetics and pharmaceuticals. 

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