Same old, same old…

More fallacy from Dennis Brady on LE:

I mean 2 – 45 deg elbows connected together to produce the 90 deg bend. The wider arc causes less air flow resistance. Even better would be a wide arc curve (these are available for metal ducting but are pretty pricey).

For at least 40 years, the plumbing code for drains and vents stated specifically that in any run of drain or vent, one only 90 was permitted but an unlimited number of 45’s was allowed. If the experts insist that makes a critical difference for venting plumbing drains, it’s reasonable to assume it’ll make a significant difference for venting torching fumes.

I guess Dennis has never looked under his sink. A standard plumbing P trap consists of at least 3, count them, 3 90 degree bends to form the drain trap. 90 degree bends are in every single plumbing run made. Continue reading

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