Tech Notes

These documents are single page technical briefs based on common questions received by the clay pipe industry.  For more detailed information, Contact NCPI's Technical Representatives.

Restoration of Vitrified Clay Pipe Lines

BACKGROUND - It has been estimated that over the last 125 years more than a million miles of clay pipe sewers have been installed in the United States. Most of this pipe is still in service. Contract...


Tech Note 04-22 Microtunneling with Clay Pipe

Microtunneling is a precise method of installing pipelines without digging trenches or dewatering. Pipe are jacked through the ground from a launch shaft to a reception shaft by the use of a laser gu...


Tech Note 08-24 Surcharge Fills

There is often considerable uncertainty about the ability of an existing sewer to support additional backfill placed over the top of the original trench. The following suggestions may be useful to th...


TN 00-13 NCPI Modifies a slurry bedding system

A new bedding system known as CONTROLLED DENSITY FILL (CDF)is introduced by NCPI. CDF, considered to be slurry, was specified to have a compressive strength of 100 psi to 300 psi at 28 days. Desired a...


TN 00-14 Knowing Your Limitations

Television has been growing in popularity as a means of investigating the condition of all types of buried sewer lines. As an investigative tool, the latest equipment is unmatched in enabling operato...


TN 00-15 Bell or Coupling Holes and Shovel Slicing

The digging of bell or coupling holes and shovel slicing of the initial bedding in haunch areas of the pipe are two critical functions that need to be part of any successful sewer pipe installation.


TN 02-17 Abrasion Resistance of Sewer Pipe Materials

The abrasion resistance of several commonly used sewer pipe materials.


TN 02-18 Classification of Soils

Soil classification using the U.S. Bureau of Reclamation method.


TN 02-19 Bedding Design for Clay Pipe

This Tech Note discusses the different bedding system's available for use when installing clay pipe. It also discusses load factors and proper installation techniques.


TN 02-20 American Society for Testing and Materials Standards Development

The process involved in the development of an ASTM Standard.


TN 03-21 Modern Clay Pipe Joints: No Longer A Case of Leaks and Root Intrusion

Discuss of history of joint development and a look at today's joint performance. Quote from Winston Salem, North Carolina about no root intrusion.


TN 05-01 "Tech Notes"

A simplified approach to the presentation of technical and sometimes complex subjects.


TN 05-03 NCPI "Toolbox"

NCPI "Toolbox" is a disk containing four NCPI developed computer programs to aid design engineers.


TN 05-23 Single Material Specifications

A discussion of relevant laws and regulations discussing sourcing for public contracts.


TN 06-04 Is Less Really Less - An Economic Approach to Sewer Pipe Selection

When comparing alternate bids of pipe with different life expectancies, the lowest initial bid is not always the best bid or in the best interest of the owner. The goal is to select the pipe material...


TN 06-05 Infiltration and Inflow Studies - What do they really show?

Early clay pipe lines were often designed to allow infiltration and inflow not only to dilute sewage, but to aid in its flow downstream.


TN 06-06 Deflection: Does it Matter?

This edition of TECH NOTES, considers two aspects of flexible pipe deflection: Structural Design and Hydraulic Performance.


TN 06-07 Vitrified Clay Pipe and Polyvinyl Chloride Pipe

An Environmental Comparison of VCP and PVC.


TN 06-08 Vitrified Clay Pipe - The Choice for Difficult Solutions

When clay pipe is vitrified, the clay mineral particles become fused into an inert, chemically stable compound, integrally bonded by its very nature, independent of any artificial bonding agent.


TN 07-09 Vitrified Clay Pipe - A Pipeline of Progress

A historical time-line of national events paralleling the development of the Clay Pipe Industry.


TN 08-10 The Decision is Yours

Selecting a particular sewer pipe material may affect the lives and pocketbooks of the people in your community for the next 100 years or more.


TN 09-11 Sand as a bedding material

Sand has been used as a bedding material in parts of the country for many years and has been presumed to be the ideal bedding material. The limitations of sand bedding are presented.


TN 09-12 Curvilinear Sewers

New factory applied joints provide angular deflection enabling installation of curved sewers.