How do I take field measurements for an OG (Ogee) offset

Plain-English answer

Measure the face-to-face distance between the two offset duct openings (this is your structural fitting length).

Measure the exact offset alignment distance along the horizontal plane (Left/Right shift) and the vertical plane (Up/Down shift).

Check for any physical obstruction interferences (like plumbing mains or electrical racks) running through that open space zone.

Note down the exact width, height, and connection types (e.g., TDC to S&D) of both the entering and exiting duct openings.

Field checklist

• Stop and verify the approved detail, manufacturer instructions, foreman direction, and project specs before touching it.
• Measure the face-to-face distance between the two offset duct openings (this is your structural fitting length).
• Measure the exact offset alignment distance along the horizontal plane (Left/Right shift) and the vertical plane (Up/Down shift).
• Check for any physical obstruction interferences (like plumbing mains or electrical racks) running through that open space zone.
• Note down the exact width, height, and connection types (e.g., TDC to S&D) of both the entering and exiting duct openings.

Ask Foreman

Verify before acting

Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.

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