Design deficiencies

Failure Cause. The failure cause is the physical, chemical, electrical, thermal, or other design deficiency which caused the failure. The agent, physical process, or hardware deficiency causing the failure mode must be identified, ie, what caused the failure for each failure mode. There may be more than one cause. Failure Fffect. The failure effect is the local effect on the immediate component/subsystem and the global effect on system performance/operation. In commercial products, the effect on the customer, ie, the global effect, must be addressed. 

Design. Design deficiencies can result in almost any combination of the problems described above. It can also result in catastrophic and significant spills. The best prevention is to use estabUshed codes, such as those provided by the API. 

A traditional checklist analysis uses a list of specific items to identify known types of hazards, design deficiencies, and potential accident scenarios associated with common process equipment and operations. The method can be used to evaluate materials, equipment, or procedures. Checklists are most often used to evaluate a specific design with which a company or industry has a significant amount of experience, but they can also be used at earlier stages of development for entirely new processes to identify and eliminate hazards that have been recognized through operation and evaluation of similar systems. To be most useful, checklists should be tailored specifically for an individual facility, process, or product. 

Several catastrophic fire incidents in the petroleum industry have been the result of the facility firewater pumps being directly affected by the initial effects of the incident. The cause of these impacts has been mainly due to the siting of the fire pumps in vulnerable locations without adequate protection measures from the probable incident and the unavailability or provision of other backup water sources. A single point failure analysis of firewater distribution systems is an effective analysis that can be performed to identify where design deficiencies may exist. For all high risk locations, fire water supplies should be available from several remotely located sources that are totally independent of each and utility systems which are required for support. 

Design category, in patents, 18 166 Design codes, for tanks, 24 303 Design deficiencies, as a cause of tank spills and leaks, 24 309... 

Particular attention should be paid to fatigue failures as they may reveal design deficiencies rather than material defects. 

The guideword process can be supplemented by additional topics/questions based on an analysis of previously experienced design deficiencies and operational incidents. For instance, ICI has collated a database of over 350 operational incidents that it uses to refine its CHAZOP Study process. Some example questions for the CHAZOP Study are given in Appendix 8E at the end of this chapter. Of particular interest to the study is the effect of partial or catastrophic failures, recovery mechanisms (e.g., rollback and roll-forward), and the general usability of the system (e.g., the need for multiple screens to access data, screen refresh times, meaningful information displays). The list of questions can be expanded with operational and regulatory experience. 

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. 

FMS Design Deficiency The FMS did not provide the pilot with feedback that choosing the first identifier Usted on the display was not the closest beacon having that identifier. 

Selection and design deficiencies are probably the most common as well as the most serious causes of problem incineration systems. Reputable incinerator contractors usually make every effort to satisfy specified design and construction criteria and meet their contractual obligations. Operating and maintenance deficiencies can usually be corrected. However, once a system has been installed and started, very little can be done to compensate for fundamental design inadequacies. Major, costly modifications and revisions to performance objectives are usually required. 

The relatively frequent occurrence of design deficient systems may largely be attributable to a general misconception of the incineration industry as a whole. Incinerators are often promoted as standard, off-the-shelf equipment that can be ordered directly from catalogs, shipped to almost any job site and literally plugged in. This impression has been enhanced by many of the incinerator vendors in a highly competitive market. Exaggerations, half-truths, and sometimes false claims are widespread relative to equipment performance capabilities. In... 

Also End flash gas used for diyer bed regeneration is currently at higher temperature due to design deficiencies in the EFG compressor after cooler. This is impacting final cooling temperature of the molecular sieve beds. 

Design Organisations are at the heart of safety because the design solution determines the manner in which the system is operated and maintained. There are many design deficiencies which require constant management and reevaluation in the Continuing Airworthiness, for instance ... 

In addition to the Chernobyl design deficiencies, there was evidence of human error and the voluntary violation of safety rules, both for production reasons and in the incorrect appreciation of the real danger. Chernobyl can with good reason be considered representative of the maximum possible accident to a power reactor. 

McGuire, (McGuire Nuclear Plant) (1988), A safety injection/Reactor trip occurred due to a design deficiency of the main turbine controls Followed by various Equipment Malfunctions, LER (Licensee Event Reports) 369-87-017-01. 

Failure of two or more structures, systems, and components due to a single specific event or cause. Typical examples include a design deficiency, a manufacturing deficiency, operation and maintenance errors, a natural phenomenon, a human-induced event, saturation of signals, or an unintended cascading effect from any other operation or failure within the plant or from a change in ambient conditions. 

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