Galvanized (zinc-coated) steel is produced with a coating weight of 610 g/m2 (2 oz/ft2) of surface (total both sides) to provide zinc coating thickness of 43 µm (0.0017in.) on each surface. Zinc corrodes much more slowly than steel in natural environments and it galvanically protects steel at small discontinuities in the coating. Its excellent resistance to corrosion is due to the formation of protective films on zinc during exposure. On the average, the rate of attack of zinc is approximately 1/25 that of steel in most atmospheres and various waters. High corrosion rates in strongly acidic and strongly alkaline solutions can be attributed to the absence of film on the metal surface (stable films are present on the surface when the corrosion rates are low).
For more information on galvanized coated corrugated steel pipe, check out the NCSPA Service Life Selection Guide, or send us your questions through our
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
.
|
The aluminized type 2 (ALT2) coating develops an oxide barrier layer on the interior pipe surface and thus performs well in areas where the presence of soft water would require a coating other than galvanized CSP. In addition to performing well in soft water conditions, CSP with an ALT2 coating performs in wider ranges of pH and resistivity. When installed in the established environmental conditions, field evaluations of CSP with the ALT2 coating have proven this material will achieve a 100+ year service life.
For more information on aluminized type 2 coated corrugated steel pipe, check out the NCSPA Service Life Selection Guide, or send us your questions through our
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
.
|
 The polymer coating was developed for use in environmental conditions that exceed those in which most materials can perform. This polymer coating is applied over the galvanized coating that was the standard coating for CSP for many decades. The presence of two coatings, and the resulting strong bond between those coatings, allows polymer coated CSP to achieve performance levels not attainable by most pipe materials and coatings. Field evaluations of polymer-coated CSP have proven that when installed within the defined site environmental conditions, this pipe can provide service well in excess of 100 years.
For more information on polymer coated corrugated steel pipe, check out the NCSPA Service Life Selection Guide, or send us your questions through our
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
.
|
There may be sites where the three coatings available (galvanized, ALT2 and polymer) on steel delivered to pipe fabrication facilities may not be the best match for the site conditions. Additional add-on service life can be provided by coating or paving the invert of CSP with asphalt either after fabrication or after installation.
For more information on asphalt coated corrugated steel pipe, check out the NCSPA Service Life Selection Guide, or send us your questions through our
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
.
Types of asphalt coated pipe:
| Service Life Ad-ons for Supplemental Paving and Coatings |
| Coatings Material |
FHWA Abrasion Level |
| 1 |
2 |
3 |
4 |
| Add-on Service Life (Years) |
| Asphalt Coated |
10 |
10 |
N/R |
N/R |
| Asphalt Coated and Paved |
30 |
30 |
20 |
N/R |
| NOTE: N/R = Not Recommended |
|
|
|
