ly to the bent watertube design, but also to the firetube and the cast iron designs. The required heat transfer surface area for any given boiler, or heat exchanger, is primarily a function of the design of that particular boiler.
Without doubt, a new boiler design must be researched, tested, and then operated in field application over a period of time to verify that performance in practice does in fact approximate closely design calculations made during development of the product.
Design calculations must also take into account all variables that may affect equipment integrity and material life. However, once this has been done, which is the case with today's bent watertube, firetube, and cast iron boiler technology, then minimum design standards which have been in place for half a century should be reviewed and amended, thus allowing for the use of improved boiler design and technological advancement. ES
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