All Raci Insulators and Spacers meet the following criteria for separating casing and carrier pipes:

  • Ensuring electrical insulation between two pipes
  • Permanently prevent bells from sliding or resting on casing pipe
  • Fastens tightly on the carrier pipe to ensure no horizontal movement during installation.
  • Made of materials which do not conduct electricity and are permanently resistant to chemical corrosion.
  • Resistance to both mechanical and thermal shock and stresses particularly during installation.

Raci Specification suggestion for Casing Spacer

Casing spacers are used to install carrier pipes inside the encasement pipe in order to provide support around the periphery of the pipe should it twist as it is pushed through the casing. Appropriate spacer selection and installation provides the best long-term protection.


The spacers should be of a projection type that has a minimum number of projections around the circumference that total the number of diameter inches. For example: 8" pipe should have a minimum of 8 projections and 18" pipe should have a minimum of 18 projections.

Spacing between spacer rings (span) should be calculated based on the actual installed load (weight of pipe filled with liquid) but should not exceed 10 feet / 3 meters. Refer to the tables in the current Raci Brochure and website for the load carrying capacity of each type of Raci spacer used.

Spacer should also have a minimum height that clears the pipe bell or as otherwise indicated on the plans.

Casing spacers should be projection type - non metallic spacers constructed of preformed sections of high-density polyethylene. Spacers should be ISO 9001:2000 certified for strength and quality.

Casing spacers should be installed using double backed tape provided with the spacers in order to fasten them tightly to the carrier pipe.

Typical Road Crossing