In the latest entry of incompetence, Dale writes on LE:
In theory 2- 45° turns will have a larger radius turn and be less restrictive to air flow than a single 90° turn….
The FACT, Dale, is that a 45 bend has EXACTLY half the pressure resistance of a 90 degree bend. So two 45 degree bends EQUALS the pressure resistance of a single 90 degree bend. And because of the additional joint that could cause some turbulence, joining two 45 degree bends to form a 90 degree bend, there is a chance that the actual pressure resistance would be slightly higher than using a single 90 degree bend.
This is what happens when two apparent know-it-alls (Dale Meisenheimer and Dennis Brady) start making things up because it sounds good. Neither of these gentlemen know a damn thing about HVAC or design issues of air flow. Neither of these gentlemen has bothered to do any research on the subject and rely instead on their “common sense” instead of using the rules of air movement.
Then Dennis goes on to write:
Plumbing codes for drains and exhaust vents permit a single 90 but unlimited number of 45’s. It would seem the mechanical engineers that make such decisions believe it’s more then theory.
PLUMBING??? We are talking about HVAC, not water. The laws are different. Code is different. And interestingly enough, (keep in mind that Dennis Brady lives in Canada, not the US) here in the US, the plumbing codes make no restrictions on the number of bends, 90 degree or 45 degree. Once again, Dennis is talking pure idiocy and has no idea about what he’s talking about.
Here’s a link to a thread over on WC where Dennis shows off his ignorance, and seems very proud of it: http://www.wetcanvas.com/forums/showthread.php?t=495062