ASHRAE Series Continued:The Most Ancient Rule Known to Engineers,the Rule of Thumb!


Continued Source:  Chapter 1,  “A Long, Strong Pull Together”

In the late nineteenth century, the science of heating and ventilation was not well understood. When installing heating and ventilating systems, most contractors based their calculations solely and unquestionably on data in fan manufacturers’ catalogues.  Only a few contractors were educated and had formal training in engineering.

Perhaps the best summary of the late 1890s was written by Stewart A. Jellett, a charter member and the second president of The American Society of Heating  and Ventilating Engineers. He explains:  “Until about 1890 the business of heating and ventilating had been largely based on the most ancient rule known to engineers, the rule of thumb…I believe it was the stress of competition, the commercial side of the business, that finally forced the recognition of the necessity for more scientific consideration, both in regard to the manufacture of the apparatus and in its application for regular work.  “Between the so-called ‘Heating and Ventilating Engineer,’ who did not understand his business, and the heating and ventilating engineer who was 75 per cent. fakir [sic], the public was getting but a poor return for its money. 

There was general ignorance on the subject of heating and ventilation, and there were any number of contractors who had patented schemes, designed to give all the heat desired at practically no expense for fuel; in fact, after reading some of the descriptive matter, one felt that a coal bin had ceased to be a necessary adjunct to any building. “The results of the efforts of contractors and engineers of this class was that the installation of steam and hot water heating apparatus was so generally unsatisfactory that the outlook for business was not favorable.”

“I now charge you, as you love the cause in which you have so recently launched your bark, to look well to your applications for membership, as the growth and perpetuity of this society rests upon this fully as much as on any other proposition.”


Membership in today’s ASHRAE is open to any person associated with building systems, particularly HVAC&R; energy efficiency; indoor air quality; and sustainability within the building industry. Membership in ASHRAE allows access to state-of-the-art built environment technology and provides many opportunities to participate in the development of said technology.

The ASHRAE proposition that began in 1894 continues.  Please join this ASHRAE webcast and learn about your industry:–conferences/webcasts


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