Principles
The terminology of inherent safety has developed since 1991, with some slightly different words but the same intentions as Kletz. The 4 main methods for achieving inherently safer design are:
- Minimize: Reducing the amount of hazardous material present at any one time, e.g. by using smaller batches.
- Substitute: Replacing one material with another of less hazard, e.g. cleaning with water and detergent rather than a flammable solvent
- Moderate: Reducing the strength of an effect, e.g. having a cold liquid instead of a gas at high pressure, or using material in a dilute rather than concentrated form
- Simplify: Designing out problems rather than adding additional equipment or features to deal with them. Only fitting options and using complex procedures if they are really necessary.
Two further principles are used by some:
- Error Tolerance: Equipment and processes can be designed to be capable of withstanding possible faults or deviations from design. A very simple example is making piping and joints capable of withstanding the maximum possible pressure if outlets are closed.
- Limit Effects: Designing and locating equipment so that the worst possible condition gives less danger, e.g. gravity will take a leak to a safe place, the use of bunds.
In terms of making plants more user-friendly Kletz also added the following:
- Avoiding Knock-on Effects;
- Making Incorrect Assembly Impossible;
- Making Status Clear;
- Ease of Control;
- Software and management procedures.
Read more about this topic: Inherent Safety
Famous quotes containing the word principles:
“Now there cannot be first principles for men, unless the Divinity has revealed them; all the rest—beginning, middle, and end—is nothing but dreams and smoke.”
—Michel de Montaigne (1533–1592)
“Only conservatives believe that subversion is still being carried on in the arts and that society is being shaken by it.... Advanced art today is no longer a cause—it contains no moral imperative. There is no virtue in clinging to principles and standards, no vice in selling or in selling out.”
—Harold Rosenberg (1906–1978)
“It must appear impossible, that theism could, from reasoning, have been the primary religion of human race, and have afterwards, by its corruption, given birth to polytheism and to all the various superstitions of the heathen world. Reason, when obvious, prevents these corruptions: When abstruse, it keeps the principles entirely from the knowledge of the vulgar, who are alone liable to corrupt any principle or opinion.
”
—David Hume (1711–1776)