The National and Southeastern Corrugated Steel Pipe Associations are responding to the Oct. 12 Times article explaining code changes in Hall County for culverts and stormwater pipes that excludes all types of metal pipe from “live streams” (perennial) and “under county roads.”
This change ignores sound product research, design and pipeline-installation practices and would do nothing to curtail future washouts such as those that occurred this year, which involved both reinforced concrete pipe and galvanized corrugated steel pipe.
The article states the Board of Commissioners set new standards for culverts and stormwater pipes, requiring new underground structures to be made of “more durable materials with higher life expectancy, so as to protect the financial resources and other interests of Hall County.”
There are many factors aside from the type of pipe that must be addressed when evaluating a culvert or stormwater system: diameter, structural design, pipe lengths, joints, bedding/backfill and pipeline end treatment protection. Nearly two years ago, when galvanized corrugated steel pipe was restricted, it was replaced with a product that meets the higher service life requirements: aluminized steel type 2 corrugated steel pipe.
No other product in history has undergone as much scrutiny, field and laboratory testing and discussion as ALT2. There are 30-year, 43-year and 50-year studies that give the product, when used in its environmental ranges (much wider than galvanized) a minimum of 75 years for 16-gauge and minimum 100 years for 14-gauge.
The article’s use of the term “rust-prone” corrugated metal pipe is misleading and unfairly portrays the product’s historical performance. Every product deteriorates over time. The specifier must first determine what “reasonable” service life is desired and then conduct research to determine what products meet those requirements. They must also evaluate and implement installation techniques such as the crucial end treatment protection against high flow and scouring.
As the county knows, the vast majority of culverts installed in Hall County and throughout the U.S. have been galvanized CMP. It was the product of choice years ago because of its light weight, long lengths, positive joints and cost, but was never promoted to be a 50-, 75- or 100-year pipe except in areas of arid climates.
Therefore, if the majority of culverts are galvanized CMP, then of course, the majority of “pipeline barrel” service life issues today are with galvanized CMP. There is no reason to eliminate other types of metal pipe, namely ALT2, because galvanized CMP doesn’t give the county the service life it desires.
The county needs to upgrade other aspects of its drainage specification aside from pipe materials, evidenced by the fact the recent washouts involved pipe materials other than corrugated steel. The code change restricting aluminized type 2 corrugated steel pipe, of which there are no documented material failures, will do nothing to curtail the multimillion-dollar experiences down the road.
We respectfully request Hall County reconsider its recent construction code changes. We stand ready to help upgrade and enhance the current specifications in order to assure the taxpayers that they are indeed getting the most reliable and cost-effective culvert and stormwater solutions.