North Carolina DOT #2

Mr. Houston Crumpler
Crumpler Plastic Pipe Company
P.O. Box 68
Roseboro, NC 28383

SUBJECT: 4″ Diameter HDPE Smooth Lined Corrugated Plastic Pipe (SLCPP) for Shoulder Drain Outfall Pipe

Dear Mr. Crumpler:

The subject material was discussed at the April 16, 1992 meeting of the New Products Evaluation Committee. The Committee assigned 4″ diameter HDPE SLCPP Approved for Usage status for shoulder drain outfall pipe installations. This decision was based upon the reported acceptable performance of this material observed at several trial projects.

The 4″ diameter HDPE SLCPP must meet AASHTO M252 Standards and be provided with watertight couplers which are suitable for gravity flow conditions. Please be advised that our Standard Specifications require the use of a three-foot section of PVC or corrugated steel pipe at the outlet end of outfall pipes. This requirement only applies if the outlet end is not connected to a drainage structure or a concrete pad.

NCDOT Roadway Standard Drawings and Standard Specifications are presently being revised to allow 4″ diameter HDPE SLCPP as an acceptable alternative to schedule 40 PVC pipe. All necessary revisions are expected to be completed in time for the July 1992 letting.

Please do not hesitate to contact me at 919-250-4128 if you have any questions concerning this subject.


Steve M. Manilla, P.E.
Chairman, New Products Evaluation Committee