Latent failure

Error conditions at various levels of the organization result from inappropriate policies, or ineffective implementation of good policies by line management. Poor practices may produce "latent failures" that are not actuated until in combination with other conditions or failure that produce an accident. 

In the case of a latent human error the consequences of the error may only become apparent after a period of time when the condition caused by the error combines with other errors or particular operational conditions. Two types of latent error can be distinguished. One category originates at the operational level and leads to some required system function being degraded or unavailable. Maintenance and inspection operations are a frequent source of this type of latent failure. 

The other category of latent failures can occur at the level of engineering design or management policy. For example, the design of a scrubbing system... 

Inadequate ergonomic design in areas such as control panels and the labeling and placement of valves on the plant can also be regarded as a latent failure because it will increase the probability of active errors. For example, a worker may misread process information from a poorly designed display. Poorly labeled and situated valves can cause the wrong valve to be selected, with possibly disastrous consequences. 

Because errors are frequently recoverable, it is also appropriate to define another category of errors, recovery failures. These are failures to recover a chain of events leading to a negative consequence (assuming that such a recovery was feasible) before the consequence occurs. This includes recovery from both active and latent failures. 

Accidents do not arise from a single cause but from a combination of conditions which may be human caused (active or latent failures), characteristics of the environment, or operating states of the plant (see Chapter 2). 

Historic incident data show that latent failures, also called latent conditions, have played an important role in incident causation. The term latent failure implies the condition is dormant or hidden. Normally the latent failure can be revealed before an incident through testing or auditing during typical operations within the process as shown in Figure 3-2. 

There is always a possibility, however, that a latent failure may remain hidden during testing. There are several reasons a latent failure may not be detected. 

Latent component failures, human errors, and related imsafe acts and errors are all results of weaknesses in our management systems. This is why the terms root cause and management system weaknesses are used interchangeably. The term latent failure or latent error is still used in some academic settings. 

Latent Failure—Failure in a component because of a hidden flaw. 

This chapter focuses on system enhancements and the checks and balances needed to proactively prevent medication errors as pharmacists and technicians prepare, dispense, and monitor the effects of medications in all practice settings. In addition, focus is placed on the importance of determining latent failures that contribute to mediation errors by developing effective medication error reporting programs to discover how latent failures occur and how they can be prevented. 

The activities charted can be categorized as ranging from normal operations through system response. In addition, some can extend back in time before the occurrence of the incident, e.g., latent failures. 

Latent failures—conditions present in the system for some time before the incident, but evident only when triggered by unusual states or events. Examples include equipment design deficiencies, unexpected configurations of munitions, or routine ignoring of standard operating procedures. 

The first study found 40 active failures (i.e., direct error precursors) and nine latent failures (i.e., dormant states predisposing the system to later errors). Four broad classes of active failures were ... 

Preventive actions, which set a periodic interval to perform planned maintenances, ignore the health status of a physical equipment/system. Therefore, they may not be adequate to oil industry systems since sometimes they would imply uimecessary actions, i.e., as system has not crossed the critical deterioration line yet. On the other hand, pre-set times for preventive actions might also not pay enough attention on the system, even if a latent failure will take place next. Both situations are cost and time consuming and should be attenuated. 

State 2 belongs to a dangerous and for validation algorithm latent failure. Its failure rate will be J.2. 

---