Mechanical drawing and shop drawing show different duct size

Hold the install until the controlling document is confirmed. Approved shop drawings, RFIs, sketches, or addenda may control, but the field should not decide alone.

Stop if

• The mechanical drawing shows [size], but the shop drawing shows [size] for the same run. Which one controls?

Watch out

• Do not choose the drawing that matches the material just because the material is already staged.

Check

• Compare revision dates and approval/status stamps.
• Check piece marks and system/area tag.
• Photo both callouts side by side.
• Ask foreman/PM which document controls.
• Do not install more of that run until direction is clear.

Steps

• Compare revision dates and approval/status stamps.
• Check piece marks and system/area tag.
• Photo both callouts side by side.
• Ask foreman/PM which document controls.
• Do not install more of that run until direction is clear.

More in Print Reading, Tags & Layout