Tools - EPA Method 1
(for port location on circular ducts only)
Criteria: Ports must not be located less than 0.5 stack diameters upstream and 2.0 stack diameters downstream from any flow disturbance.
Disturbance: Any bend, expansion, contraction, conversion, connection, or other solid obstruction located within a duct.
Important Notes:
- The spreadsheet above can be used to calculate equivalent upstream and downstream stack diameters. Just input the inside stack diameter, making sure not to include ports or obstructions.
- This criteria applies to both vertical and horizontal, circular ducts. Verify the direction of the gas flow before calculating upstream and downstream diameters.
- Measurements must be taken from the center of the port, and from the upstream and downstream disturbance-points closest to the port.
- The best case scenario for port location is at least 2.0 diameters upstream and 8.0 diameters downstream from any flow disturbances.
- Ports need to be installed on the same horizontal plane, perpendicular to the direction of the flow.
- Ports should have a coupling length of 5-6 inches from the outside stack wall and be 4 inches in diameter. The ports should also be able to support at least 75 pounds. If PM10 measurements are necessary (now or in the future), port diameters should be 6 inches.
- Make sure all ports are grinded out and that the couplings do not extent past the inside stack wall.
- On vertical stacks, eyelets should be installed directly above each port (approximately 30 inches).
