Specifications
Review ASTM and AASHTO references, material properties, dimensions, and installation notes for design and submittal work.
Open the spec pageCulvert Liner Flow Capacity for Culvert Renew® Liners
Full-flow comparison at 1% slope using Manning’s equation: legacy host pipes vs. smooth-bore HDPE culvert liner.
Typical roughness: CMP n = 0.024, RCCP n = 0.015, Renew Liner n = 0.009.
Method & Assumptions
Charts compare full-pipe flow at 1% slope using Manning’s equation. The smoother liner (n ≈ 0.009) often offsets the reduced diameter during slip-lining, and in many sizes increases full-flow capacity versus deteriorated corrugated metal pipe (CMP).
Results are shown both against CMP (n = 0.024) and RCCP (n = 0.015) for common host/liner size pairs. If the project team is still deciding whether rehabilitation or excavation is the better path, pair this chart with the culvert liner overview and the reline-vs-replace guide.
What does “% Flow” mean?
It’s the ratio of calculated liner flow to host pipe flow at the same slope and full condition. > 100% means the liner passes more flow than the host.
- CMP n = 0.024 • RCCP n = 0.015 • Renew Liner n = 0.009
- Full-pipe condition at 1% (S = 0.01)
- Pairs reflect common host → liner IDs used in rehab
Percent of Host Flow (Full @ 1% Slope)
CMP vs Liner — Liner % of Host Flow (full, 1% slope)
Bars show liner flow ÷ host flow × 100. Host roughness: CMP n = 0.024; Liner roughness: n = 0.009.
Scale up to 180%
Host CMP 12" → Liner 10"
164%
Host CMP 15" → Liner 12"
147%
Host CMP 18" → Liner 13.5"
124%
Host CMP 18" → Liner 15"
164%
Host CMP 21" → Liner 15"
109%
Host CMP 24" → Liner 18"
124%
Host CMP 27" → Liner 21"
136%
Host CMP 30" → Liner 24"
147%
Host CMP 33" → Liner 24"
114%
Host CMP 36" → Liner 27"
124%
Host CMP 42" → Liner 30"
109%
Host CMP 48" → Liner 36"
124%
Host CMP 54" → Liner 40"
120%
Host CMP 60" → Liner 42"
103%
Host CMP 66" → Liner 48"
114%
Host CMP 72" → Liner 54"
124%
Host CMP 78" → Liner 54"
100%
Host CMP 84" → Liner 60"
109%
Host CMP 96" → Liner 72"
124%
Host CMP 120" → Liner 84"
103%
Values computed via Manning’s equation for full-pipe flow at 1% slope, using the provided chart dataset.
CMP (n = 0.024) vs Liner (n = 0.009)
Based on pipe flowing full at 1% slope.
| CMP ID (in.) | Liner ID (in.) | CMP Flow | Liner Flow | % Flow |
|---|---|---|---|---|
| 12 | 10 | 866 | 1,419 | 164% |
| 15 | 12 | 1,569 | 2,308 | 147% |
| 18 | 13.5 | 2,552 | 3,160 | 124% |
| 18 | 15 | 2,552 | 4,185 | 164% |
| 21 | 15 | 3,850 | 4,185 | 109% |
| 24 | 18 | 5,497 | 6,806 | 124% |
| 27 | 21 | 7,526 | 10,267 | 136% |
| 30 | 24 | 9,968 | 14,659 | 147% |
| 33 | 24 | 12,853 | 14,659 | 114% |
| 36 | 27 | 16,210 | 20,070 | 124% |
| 42 | 30 | 24,453 | 26,581 | 109% |
| 48 | 36 | 34,913 | 43,226 | 124% |
| 54 | 40 | 47,799 | 57,251 | 120% |
| 60 | 42 | 63,307 | 65,207 | 103% |
| 66 | 48 | 81,629 | 93,102 | 114% |
| 72 | 54 | 102,950 | 127,463 | 124% |
| 78 | 54 | 127,449 | 127,463 | 100% |
| 84 | 60 | 155,301 | 168,818 | 109% |
| 96 | 72 | 221,737 | 274,534 | 124% |
| 120 | 84 | 402,066 | 414,136 | 103% |
RCCP (n = 0.015) vs Liner (n = 0.009)
Based on pipe flowing full at 1% slope.
| RCCP ID (in.) | Liner ID (in.) | RCCP Flow | Liner Flow | % Flow |
|---|---|---|---|---|
| 12 | 10 | 1,385 | 1,419 | 102.5% |
| 15 | 12 | 2,511 | 2,308 | 91.9% |
| 18 | 15 | 4,084 | 4,185 | 102.5% |
| 21 | 15 | 6,160 | 4,185 | 67.9% |
| 24 | 18 | 8,796 | 6,806 | 77.4% |
| 27 | 21 | 12,042 | 10,267 | 85.3% |
| 30 | 24 | 15,949 | 14,659 | 91.9% |
| 33 | 27 | 20,564 | 20,070 | 97.6% |
| 36 | 30 | 25,936 | 26,581 | 102.5% |
| 42 | 36 | 39,124 | 43,226 | 110.5% |
| 48 | 40 | 55,861 | 57,251 | 102.5% |
| 54 | 42 | 76,478 | 65,207 | 85.3% |
| 60 | 48 | 101,291 | 93,102 | 91.9% |
| 66 | 54 | 130,607 | 127,463 | 97.6% |
| 72 | 60 | 164,720 | 168,818 | 102.5% |
| 84 | 72 | 248,482 | 274,534 | 110.5% |
| 96 | 84 | 354,780 | 414,136 | 116.7% |
| 120 | 96 | 643,306 | 591,300 | 91.9% |
Note: For some pairs the RCCP host (n = 0.015) exceeds the liner capacity.
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