Twinwall Jointing Procedure for Sealed System:

For 63mm,110mm,120mm,145mm, 160mm and 178mm DUCT

1. Always ensure that the pipe end is free from dirt, grit, soil etc.
   • Remove any damaged end sections of the pipe.
2. Place the seal within the 3rd valley of the twinwall corrugated pipe. (2nd valley for 160/137 and 178/150mm pipe)
   • Ensure both pipe ends are raised off the ground before lubricating to ensure no grit or dirt is picked up when lubricant is applied.
3. To help place the seal in the valley lubricate valley before fitting.
   • • Lubricate around the outside edge of the seal and pipe, also lubricate both internal sides of the coupler using Naylor lubricant.
4. Push the coupler onto the pipe with seal, ensuring the pipe end is flush with the central stop positioned within the middle of the coupler.
5. Place the next pipe inside the coupler and push the pipe with seal into the coupler.
6. Air test – Test inline with current Highway specifications, ensuring that the correct test equipment is used (4″ ‘U’ Gauge).
7. Installation – Follow all current Highway specifications, ensuring that the correct bedding material is used.
8. Pipes which require cutting to size, should be cut using a course toothed saw. Cuts should be made in the valley section of the pipe and should be square to the axis of the pipe. Before jointing, ensure the pipe ends are free of sharp edges, swarf, grit and handling damage.
9. If this procedure is not followed and Naylor lubricant is not used, the air tight system guarantee is invalid.