What Is Culvert Inspection?
A culvert inspection is a check of the condition of a culvert, which is a pipe or box section that carries storm water.
Culverts on airfields
The FAA covers pipe culverts, precast box culverts and storm drains in one construction item, Item D-701 of AC 150/5370-10H. AC 150/5320-6G, section 5.1, names culverts among the airport structures. Their evaluation assesses the ability to support aircraft traffic.
Inspection of new pipe
AC 150/5370-10H says to inspect the pipe before the contractor places overfill. The contractor removes and relays or replaces a pipe that is out of alignment, unduly settled or damaged. A post-installation inspection follows no sooner than 30 days after the final backfill.
The specification gives these options:
- A camera that sees the full pipe interior. It must pan and tilt, and the report includes a copy of all video.
- A walk-through visual inspection for pipe larger than 48 inches (1.2 m).
- ASTM C1840 for reinforced concrete pipe.
- A deflection check of flexible pipe with a laser profiler for diameters of 48 inches or less, or by direct measurement for larger pipe.
The specification also names defects that need repair or replacement. These are cracks with displacement across the crack, bulges, creases, tears, spalls and delaminations.
Culverts and bridges
In the US, a structure is a bridge when its opening is more than 20 feet (6.1 m) along the roadway center. Inspectors must inspect a bridge at intervals of 24 months or less. Smaller culverts fall outside this definition.
Scope of this page
TarmacView does not inspect culverts. Its drone work covers airfield lighting and pavement.
Frequently Asked Questions
- How does the FAA specify the inspection of new culvert pipe?
- The FAA standard specification for storm drain and culvert pipe requires a post-installation inspection. The resident project representative (RPR) performs it no sooner than 30 days after the final backfill. The lines are cleaned or flushed first. The specification offers a camera inspection of the full pipe interior and a walk-through inspection for pipe larger than 48 inches (1.2 m).
- How much deflection is allowed in an installed flexible pipe?
- The FAA specification limits deflection to 5 percent of the average inside diameter for corrugated metal, thermoplastic and fiberglass pipe. The limit is 3 percent for concrete-lined corrugated metal pipe. Isolated areas may exceed the limit by 2.5 percent if the RPR agrees. A pipe with more deflection is removed and replaced.
- When is a culvert a bridge in the US?
- A structure is a bridge under 23 CFR 650.305 when its opening along the roadway center is more than 20 feet (6.1 m). Multiple pipes also count when the clear distance between openings is less than half of the smaller opening. Each bridge must be inspected at intervals of 24 months or less, under 23 CFR 650.311.
References
- faa-ac-150-5370-10h
- AC 150/5370-10H, Standard Specifications for Construction of Airports FAA
- faa-ac-150-5320-6g
- AC 150/5320-6G, Airport Pavement Design and Evaluation FAA
- cfr-23-650-305
- 23 CFR 650.305, Definitions (National Bridge Inspection Standards) US Government (via Cornell Legal Information Institute)
- cfr-23-650-311
- 23 CFR 650.311, Inspection interval US Government (via Cornell Legal Information Institute)
This is a reference entry. TarmacView provides drone inspection services and doesn't sell the equipment or materials described in this glossary.
