You will see that the assembly is made up of two pipes.
No loss exhaust stack cap.
See i said you explained it better.
Most other solutions drastically reduce exhaust velocity and some actually force the exhaust down where it can linger build up and get drawn into hvac or fresh air makeup systems.
This configuration is based on the principle that rain falls at an angle.
Sometimes the termination can even be turbulent enough to compromise the exhaust system.
No loss stackheads protect exhaust fans from weather increased resistance causes the fan to use additional power to maintain the calculated cubic feet per minute cfm rate required for the system.
Any fume hood mechanical system without one is incomplete.
Flanged end provides for wire guide security.
The exhaust source is offset from the stack and drainage features in the stack direct any water flow away from the exhaust source.
Exhaust stacks do not use weather caps.
And the cap length should be 4 times the diameter of the main stack.
No loss stack head provides weather protection while it eliminates back pressure on the fan.
To correct this the central exhaust duct is surrounded by the larger duct of the no loss stack and extends up higher than the central duct and is.
The contaminated air will continuously meet with resistance at the end cap quickly resulting in corrosion of the ductwork and a tumult of eddying fumes.
Nordfab stackheads are designed to be used when exhausting fans or stacks through a roof.
This video demonstrates the correct installation and operation of a nordfab no loss stackhead.
A zero pressure weathercap can save the day.
The over lap between the cap section and main stack only needs to be 6 inches.
So if the main stack is 12 inch diameter you should use a 54 inch section of 14 inch diameter for the cap.
4 times 12 48 plus the 6 inch overlap 54.
No other stack termination will give you the positive effects for pollution control that the no loss stack head will.
The inner stack is surrounded by an outer stack with space between the two.
Losses associated with them may also have other system effects no loss stacks stack diameter d 1 stack height 4d 6 d duct diameter maintain discharge velocity of 3 000 fpm weather cap no loss stack d.
Stackheads eliminate back pressure on the fan while providing weather protection.
