I've been going over Señor Gil's venting values. Again.

JohnNY

The testing, in my interpretation, states two Gorton #2 vents pass the same cfm as a ½" tapping in the pipe. It stands to reason then that one #2 would vent the same as a ¼" tapping. Roughly.



Can we then assume a Gorton #2 would consistently equal each ¼" of tapping size?



In other words: 1" tapping is the same cfm as four #2 vents? 1-¼" = five #2's?



Your studies also suggest a Gorton #1 vents similarly to a ⅛" tapping.



Is it your opinion this is a decent rule-of-thumb for venting based on available tappings, or a guide to what size tapping to add?



The testing is brilliant and the industry of installers owes a debt of gratitude to Gil and Pajek for the work they've done.



Many thanks,

John Cataneo

gerry gill

im thinking no..

Because when you double a pipe size, you quadruple its square inch area...so I'm thinking that rule of thumb wouldn't work..but my math skills are about those of a first grader' :-) so hopefully someone can help us there.

EzzyT

math is right

the square inches do quadruple as the size doubles. what i took from yours and steves testing and findings was took those numbers square feet a minute of venting and did the math of the square footage total of the piping and install the right amount of vents needed to vent the total pipe square footage. just like in any other way we all do a piping distribution load

JohnNY

ahhh

That makes sense. I'm thinking about pipe volume doubling (roughly) with each incremental size, so maybe my theory only works going from ½" to ¾".



So, that math suggests you'd max out capacity at 2 for ¾" and 4 for 1".



I shouldda stayed in school....

EzzyT

4 for 3/4"

in gerrys and steve venting chart the gorton #2 vents at 2.2 cfm at 3 oz of pressure so youd need 4 of them on a 3/4" tapping

SWEI

Square area

http://www.engineeringtoolbox.com/ansi-steel-pipes-d_305.html for steel pipe.  Note the "internal transverse area" column.

JohnNY

A lot of good info there.

From the study:

"A ¾’’ pipe at 3 ounces pressure from the boiler will pass 9.5 cfm. A Gorton #2 air vent at 3

ounces of pressure will pass 2.2 cfm. So 9.5 divided by 2.2 = 4.31 Gorton #2 vents. Now if four

Gorton #2 air vents deliver 8.8 cfm at 3 ounces of pressure, is the fifth Gorton #2 vent worth the

money to gain just .7 cfm? We don’t think so, but a Gorton #1 as your fifth air vent would max

out the cfm potential, and that would be a good choice."