I N N O V A T I O N A N D F L E X I B I L I T Y
T H E
I N S T A L L A T I O N A N D M A I N T E N A N C E T R A I N I N G M A N U A L
3.10 Installation into slots
For city and FTTH applications
protected microduct products can be placed in pre-cut slots in the roadway. The slot width
should be kept to a minimum so as not to disturb the integrity of the road.
When re-instating the road surface local laws may determine the procedures to take, but here Emtelle describe two solutions.
1. Once the protected microduct (Direct Buried) has been placed, the slot can be loosely fi lled with cold ‘Bitucrete’ (bitumen coated fi ne
gravel). This is then compacted with a steel wheel with an approximate weight of 9kg (20lbs), leaving maybe 45mm depth left to fi ll.
Process example: The bitumen is heated to 180°C in a large vessel. The hot liquid bitumen loses heat rapidly and by the time it reaches
the microduct product the heat has reduced to a level which does not cause damage. The hot bitumen is applied from a large pot fi tted
with a nozzle. The fi rst layer seeps down through the Bitucrete, air bubbles emerging. This creates a gravel-fi lled bitumen layer. After four
minutes the fi rst bitumen should be setting well, and the next layer is applied, leaving just 10 to 15mm of slot to fi ll. Four minutes later
the third (fi nal) layer may be applied. This is either fl ush with the existing road surface, or slightly over / under depending on the undula-
tions of the road.
2. The second method uses fl uid concrete to fi ll the slot to within 12-15mm (1/2 inch) from the top. Once this concrete has set, oxidised
bitumen can be used to complete the slot and return the road to its original state.
When multiple protected microduct products need to run inside a slot they must be managed so that the fl uid concrete can fi nd its way
around all the products. This is achieved using duct separators and wedges. The products are wedged to prevent the microducts moving in
the slot.
3 Outdoor Installation
“This document is intended as a guide only. Whilst the information it contains is believed to be correct, Emtelle can take no responsibility for actions taken based on the information contained in this document. Emtelle reserves the
right to make changes to this document without notice. All sales of product are subject to Emtelle’s terms and conditions of sale only, which can be found on Emtelle’s website.”
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