40 www. refrigerationandaircon. co. za RACA Journal I January 2026
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Place over the refrigeration pipe and proceed to brush coat the slit ends with adhesive. Allow to dry until slightly tacky and press together the split ends. Take care not to stick the insulation to the tubing.
Correct cutting technique.
All piping insulation must be properly sealed to minimise heat loss and control condensation. On cold lines, open pipe insulation joints may allow the formation of condensation.
In principle, tube material can simply be slid around bends. Using rotational movements while pushing can ease the process.
Place the slit tube onto the clean pipe; apply a thin, even film of adhesive to the two cut edges using a short bristle brush. Apply the adhesive along the tube length.
Application of adhesive. Allow the adhesive to tack dry, then test with the fingernail.
Twisting technique.
Note: Always apply and push the insulation tube over the pipe as shown, making sure that the longitudinal seam is arranged to the side but neither to the throat nor to the back area.
Should the insulation kink, the calculated insulation thickness is then no longer achieved, and condensation can occur on the surface of the insulation. When installing tubes with a self-adhesive seal, there is the additional risk of compression of the adhesive lining in the bend area, which can lead to seams coming apart.
Using gentle pressure to join the edges of the insulation.
Free the seams from the pipe where applicable, align the edges and press the seam detail with firm, even pressure to finish.
FOR NEW INSTALLATIONS You simply slip a length of insulation over the pipe or copper tubing, as shown below. The inside of the insulation is coated with a powdered dry lubricant, making it easy to slip the insulation over the pipe( you can use talcum powder). This dust must be kept out of refrigeration systems. Plug the open ends of the pipe before installation.
Use insulation pieces as long as the pipe work, keeping joints to a minimum. Always use the insulation that is properly sized and do not stretch it over the tubing. Do not crowd insulationcovered pipes. Space pipes far enough apart to allow for the free circulation of air. Air movement is an extra safeguard against surface condensation of cold pipes, especially under hot, humid conditions.
Kinked insulation.
The following should be taken into account in these cases: If the insulation kinks and the adhesive seam is compressed, the bends should be cut into segments to fit. In such cases, it is recommended to use standard, non-self-adhesive, tubes.
USING ADHESIVE CORRECTLY Always follow the manufacturer’ s instructions. Before use, always shake off the adhesive thoroughly. Decant small amounts to prevent the pot from drying.
Use a brush with short, stiff bristles and apply adhesive in a thin, uniform layer to both surfaces to be joined. Adhesives can become tacky within 2 – 5 minutes after application. This time will vary according to ambient temperatures and relative humidities. Avoid‘ open times’ in excess of 10 minutes.
Allow the adhesive to‘ tack dry’. The correct initial drying period can be checked by using the‘ fingernail test’. Touch the surface with a fingernail. If the surface feels tacky and your fingernail adheres to it, the joint may be closed. If the surfaces are left to dry for too long a period, they will not adhere when
40 www. refrigerationandaircon. co. za RACA Journal I January 2026