7
IOM D-040L 2”
2.2. Conventions and Measurements
This paragraph presents and explains the terms and
measurements used for the Installation process.
D = Diameter of pipeline
d = diameter of riser
H = Height of riser on the pipeline
(Measured from crown of pipeline)
•
For pipelines up to 12" (300mm) in diameter (D), the Air Trap
diameter (d) should be the same as the pipeline diameter.
•
For larger pipelines of up to 60" (1500mm) in diameter (D),
the Air Trap diameter (d) should be 60% of the pipeline
diameter.
•
For larger than 60" (1500mm) pipelines (D), the Air Trap
diameter (d) should be 35% of the pipeline diameter.
•
The Air Trap length (H) should allow easy access to the air
valve from below and should be at least 6" (150mm).
Isolation Valve
Air Trap
Riser
D
H
d
