Credibility

Both Eqs. (5.9) and (5.10) predict rate laws which are first order with respect to the concentration of each of the reactive groups the proportionality constant has a different significance in the two cases, however. The observed rate laws which suggest a reactivity that is independent of molecular size and the a priori expectation cited in item (5) regarding the magnitudes of different kinds of k values lend credibility to the version presented as Eq. (5.9). 

The subsequent step is to identify the various scenarios which could cause loss of control of the hazard and result in an accident. This is perhaps the most difficult step in the procedure. Many accidents have been the result of improper characterization of the accident scenarios. For a reasonably complex chemical process, there might exist dozens, or even hundreds, of scenarios for each hazard. The essential part of the analysis is to select the scenarios which are deemed credible and worst case. 

Aside from designs and plants, inventions are required to exhibit usefiilness or utiHty to be patentable. In fact, issued patents for processes, machines, compositions, and articles are often commonly referred to as "utiHty" patents. Depending on the nature of the technology, a single assertion of utiHty may suffice. In other cases, such as in the field of biotechnology, a more elaborate demonstration of utiHty may be necessary. Although utiHty maybe supported by an assertion of use, appHcation, or benefit, the assertion must be accurate and credible to ensure the enforceabiHty of any patent reHed upon to cover the invention. 

Where technology is central to competitive success, such a breakdown in the management of technology can become a serious threat to long-term corporate performance. This situation has created a challenging environment for technology leaders as they stmggle to reestabUsh their credibility and reassert their leadership in the business. 

Success, whether achieved in the 1950s or 1990s, involves extremely credible technical leaders who have gained the confidence of the business community by deHvering technology with significant business impact. 

While most companies within the process industries recognize the importance of information technology in managing their businesses, this technology has been a source of considerable frustration and disappointment. Schedule delays, cost overruns, and failure of the final produc t to perform as expec ted have often eroded the credibility of information technology. However, immense potential remains for the technology, and process companies have no cnoice but to seek continuous improvement. 

The goals of the F EI are to raise awareness of loss potential and identify ways to reduce potential severity and potential dollar loss in a cost-effective manner. TLe index number has significance as a comparison and in calculations to estimate the maximum probable property damage (MPPD). It also provides a method for measuring tbe effect of outage (plant being shut down) on the business. It is easy for users to get credible results with a small amount of training. 

The first step in scenario selection is to identify all the credible emergencies using the preceding guidehues (or a similar set). This is perhaps best accomplisned by identifying all the possible sources of pressure and vacuum. Table 26-7 hsts a number of commonly existing pressure and vacuum sources. 

Review of planned operation of process, especially the possibility of upsets, modes of failure, unexpec ted delays, redundancy of equipment and instrumentation, critical instruments and controls, and worst-credible-case scenarios... 

All single events that can actually and reasonably occur are credible scenarios. 

Scenarios that require the coincident occurrence of two or more totally independent events are not credible design scenarios. 

Scenarios that require the occurrence of more than two events in sequence are not credible. 

A failure that occurs while an independent device is awaiting repair represents but one failure during the time frame of the initiation of the emergency and is therefore credible. The lack of availability of the unrepaired device is a preexisting condition. 

Dispersion modeling of credible worse case scenarios indicates the one-hour exposure to nearest human receptor exceeds ERPG-2 level or equivalent. 

Operations The QRA team will need specific data on how the system is actually operated. For example, are the bypass valves normally left open to increase throughput, what happens when the high level alarm sounds, or do operators bypass interlocks to continue production Human actions/errors are usually dominant contributors to the real-world risks, and truthful data on actual process operations are vital to credible QRA results. Expect to commit one full-time equivalent for the life of the project. 

Credibly communicating risk information in the public arena... 

The effective use of risk results demands not only selecting appropriate means of establishing the credibility of the results, but also considering the audience who is or will inevitably become aware of or review those... 

If you do not listen to people, you cannot expect them to listen to you. Communication is a two-way activity. Do not make assumptions about what people know, think, or want done about risks. Take the time to find out what people are thinking. Often, people are more concerned about issues such as trust, credibility, competence, control, voluntariness, fairness, and compassion than about mortality statistics and the details of QRA. Use techniques such as interviews, focus groups, and surveys to gauge what people are thinking. 

In communicating risk information, trust and credibility are imperative. If you do not know an answer, say so, then get back to those people when you do have an answer. Discuss data uncertainties, strengths, and weaknesses, including ones identified by other credible sources. Identify worst-case estimates as such, and cite ranges of risk estimates when appropriate. 

Coordinate and Collaborate with Other Credible Sources... 

Devote time and resources to building bridges with other organizations. Use credible and authoritative intermediaries. Consult with others to determine who is best able to answer questions about risk. Few things make risk communication more difficult than conflicts or public disagreements with other credible sources. 

If the potential is parabolic, it seems credible that the inverted barrier frequency A should be substituted for the parabolic barrier transparency to give the dissipative tunneling rate as... 

Sufficient charge must be available to supply the required critical surface charge density. Calculations show that 50-pound plastic bags and plastic lined 55-gallon drums are too small to represent a credible risk. 

If it is assumed that explosible dust will be present above the MEC, and equipment design data are not required, explosibility testing forP g, and Kg usually has no direct application. However, minimum ignition energy (MIE) testing should be considered to help determine the likelihood of ignition. Since MIE is extremely sensitive to particle size it is especially important to test a sample that is sufficiently fine to represent the worst credible case. 

---