Re: [PipingDesign] Webresource for Piping design assignments

On Apr 26, 2007, at 1:08 AM, Paul Bowers wrote:

> One thing that I've found since the "computerization" of some
> engineering is that there is not so much checking of details. It is
> assumed that the model from before will work now.
I think what you're looking at is work from people without the breadth to distinguish important details like weld design and fabrication methodology from trivial details that don't affect function. How many posts have we seen from engineers and designers looking to specify materials who haven't the slightest idea what the criteria might be and what specifications require? I'm constantly amazed at the blunders and ignorance I've run into using the ASME Code, which is certainly not rocket science. I make a pretty good living using computers with pressure vessels and piping, but there are too many people who assume that the software does their thinking for them and handles the details. 'Tain't so, McGee.

> The problem that I see now is that there is not much perceived
> difference between "OK design" and "good design". Good design is
> always
> hard to quantify, and how does one differentiate between "good design"
> and "over-spending" in these days?

I don't think 'good design' is all that hard to quantify. Examples are everywhere. First is attention to detail. Japanese cars got their foothold in this country becasue the Japanese designers paid attention to details and weren't afraid to add a couple of bucks to the price of a car if it made the car more salable. My 1962 Corvair was a great example. I really liked the car, but it was not well designed compared to the other rear engine, air cooled opposed cylinder cars--Porsche, VW and Karmann-Ghia. It leaked oil because of crappy seal design, the heater allowed exhaust fumes into the passenger compartment because of cheap ducting and it needed a better suspension and steering. Most of these were details that wouldn't have cost much to fix, but GM decided that OK was what they wanted, and their reputation really suffered as a result. They could have had a world class vehicle in the Corvair, but they went for the bottom of the barrel. Ford had its Pinto and Pontiac had its Fiero. GM is littered with examples of rotten engineering and they're paying for it now.

The difference between 'quick and dirty' and 'works first time all the time,' is simply a matter of understanding the engineering. It really shows up in the details. A designer who knows how a piping system or a pressure vessel is actually built and used is a better engineer than a CAD monkey who only knows how to concoct solid models that look good. I think the reason people don't know the difference between good design and dreck is too many manufacturers don't care about engineering these days and think the GM model is the way to go. Sometimes I really do wonder if engineering is really a dying profession.

Christopher Wright P.E. |"They couldn't hit an elephant at chrisw@skypoint.com | this distance" (last words of Gen.

.......................................| John Sedgwick, Spotsylvania