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 casing 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.
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
STEP 1 - INITIAL MAKE UP
Insert the male end into the slot of the next spacer, engaging it to the 2nd marker tab. Continue in this fashion until you have a belt of elements ready to wrap around the carrier pipe.
STEP 2 - TAPING
Apply double-sided tape to the outside of the carrier pipe where the spacer ring will be located, via this method:
a.) Wrap the tape around the entire circumference of the pipe, ensuring that the width of the tape is equal to or wider than the width of the Raci element being used.
b.) Peel the tape backing off to exposing the outside face of adhesive. Leave this step until just before you are ready to place the ring on the carrier.
STEP 3 - WRAPPING
Wrap the spacer belt loosely around the pipe and close the ends by hand up to the 2nd tab, same as in Step 1.
STEP 4 - INITIAL TIGHTENING
Use the Raci Tool to tighten each spacer element connection evenly up to the 3rd tab. Periodically check alignment to make sure the spacer ring is still square to the carrier pipe, and is on the tape applied in Step 2.
STEP 5 - FINAL TIGHTENING
Continue to work around the spacer ring with the Raci tool to gradually and evenly tighten the ring around the carrier pipe. Each element should have about the same number of tabs engaged.
STEP 6 - CONTINUE INSTALLATION
Repeat Steps 1 – 5, spacing the element rings out per the spacing information provided with the Sales Quotation or Sales Order until the entire carrier pipe has spacer rings installed. Once tightened, the spacer ring and carrier pipe are ready to be installed into the casing.
CARRIER INSERTION NOTES
If carrier pipe is pushed into the casing, note the required number of lead and tail rings on the push, and ensure that these are installed prior to starting