Conversion factors, approximate

Conversion factors can be easily remembered if altered slightly, but not significantly enough to affect shortcut calculations. Here are some examples  

Branan, C., Rules of Thumb for Chemical Engineers, 2nd ed., Gulf Publishing Co., Houston, TX, 1998. 

Perry s Chemical Engineering Handbook, 7th ed., McGraw-Hill, 1997. 

Shortcut equipment design methods are difficult to define. I was asked to speak at a session on Shortcut Equipment Design Methods at the 1985 ASEE Annual Conference in Atlanta, Georgia. My paper on Development of Shortcut Equipment Design Methods is reproduced in Appendix 5. My introduction doesn t attempt to define these elusive methods instead I ducked the issue and just gave a simple example. 

Shortcut Equipment Design Methods tend to become buried in design procedures, even computer-based ones. Therefore they often become part of the mix and don t stand free as separate entities. This is not bad. These methods need to be placed wherever they are useful. However, it is also good to draw them out since many everyday problems can be solved with undiluted shortcuts. 

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Some approximate conversion factors to SI units are given in Table 1.1. These are worth committing to memory, to give some feel for the units for those more familiar with the traditional engineering units. The exact conversion factors are also shown in the table. A more comprehensive table of conversion factors is given in Appendix D. 

Below is a list of approximate conversion factors, useful for "back-of-the-envelope" estimates. None of them is exact, but most are accurate to within about 10%. Use Table A.l (App. A) to establish the exact conversions. 

It is convenient to bear in mind the approximate conversion factor 1 eV per particle = 23 kcal per mole of particles. 

A number of approximate conversion factors for the derived units most frequently encountered in the field of adhesion and adhesives are presented in Table VI. These are adequate for converting quantities to SI units in most cases. 

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