FAQ

Frequently Asked Questions

Installation:

Products:

 

Installation:
1. What is expected blowing performance of this cable in this micro-duct?
This is very frequent question of all customers. What blowing distance should we expect when we will use this cable and your micro-duct of this diameter. Unfortunately there is no simple answer and no simple table of achievable lengths.

Anyway, if you will follow standard installation procedures, use professional equipment and your micro-duct route is high quality with no extreme bends then blowing cable is very effective method with average achievable distance of 1000m. When all parameters are close to ideal, distance of 2000m can be within the reach. Blowing speed is between 25 – 50m/min.

Apart from all mentioned above, preconditions for good performance includes the high quality micro-cable and micro-duct. Not using top quality products decrease blowing performance and blowing distance can drop down close to nothing under the extreme circumstances.

Micro-cable & Micro-duct parameters
The high quality components are fundamental for good blowing performance. Using low quality, cheap materials decrease blowing performance and increase price of installation.
The most important parameters:
Micro-cables:
•    Adequate cable OD to micro-duct ID (filling ration within limits)
•    Ovality and fixed OD
•    Cable jacket material/quality (PE, PVC, ...)
•    Stiffness – avoiding kinks inside MT but also flexible enough to copy micro-duct route.
Micro-ducts:
•    Inner layer – special low friction layer
•    Ovality – max. 5% guaranteed production calibration
•    Fixed and stable dimensions

Please contact your suppliers to provide you with product specification.

Cable OD / Microduct ID RATES

 

               Theoretical calculated values

Proved by practice   (500-1000m achieved)

ID Microduct [mm]

OD Microcable IDEAL [mm]

Filling ratio [%]

OD Microcable MAXIMUM [mm]

Filling ratio [%]

Recommended  max. cable OD [mm]

Filling ratio [%]

3,5

1,8

25%

3,0

75%

2,1

36%

5,5

2,8

25%

4,8

75%

3,9

50%

8

4,0

25%

6,9

75%

6,3

62%

10

5,0

25%

8,7

75%

7,6

58%

12

6,0

25%

10,4

75%

9,7

65%

14

7,0

25%

12,1

75%

10,5

56%

2. What is the correct procedure of cable-blowing into your micro-ducts?
The good and effective blowing procedure is the matter of following basic installation rules, experience, quality equipment & material. There is now exact way to calculate or predict the maximum blowing distance, but you can increase your performance by following basic rules:
a)    Use proper blowing equipment
•    Compressor with pressure till 15 bars – each extra bar over 10bars can add some extra length
•    Professional blowing machine like Plumetaz, Lancier etc
•    Well trained and skilled operators, certified by Blowing machine producer or Duraline CT
b)    Follow proper blowing procedure
•    Keep you equipment always clean and in good condition
•    Integrity test is a must before blowing cable
•    Use correct amount of lubricant if necessary (according to manufacturer instructions). Too much lubricant works as an adhesive!
•    Always spread the lubricant by blowing sponge.
•    Ideal ambient temperature range is between 5° to 20°C.
•    As a rule always blow downhill wherever possible. Make sure that the average route will permit the cable to be installed on a descending and not an ascending gradient.
•    As far as possible the cable should not touch the ground. Figure of eight should be laid on a tarpaulin. Care should be taken to ensure that the cable as it is fed into the machine does not touch the ground.
c)    Micro-cable quality
•    Dimension tolerance within 0.1mm
•    Clean surface
•    Certified and tested for the blowing into HDPE microducts
•    Use cable lubricator if available
d)    Filling ratio within recommended limits (25% < FR < 75%)
 

3. Can I install micro-ducts above the ground, exposed to sun rays and temperature changes?

YES, but only under special conditions. All plastic materials are affected by temperature changes and UV rays.
Therefore UV-stabilizers has to be present in all micro-ducts used for exposed installation. This is not a standard production additive and therefore this must be specified in your purchase order.

Furthermore, thermal dilatation of micro-ducts is a well-known phenomenon caused by the chemical composition and properties of the material (Polyethylen). Polyethylen expands or contracts according to the changes of environment temperature.  As the result temperature-related expansion and contraction of micro-ducts may occur when installed outdoors.
This can cause severe damages to your duct-route if not installed correctly.
For further info see Outdoor Installation of Microducts.pdf
 

 

Products:

1. What is the minimum bend radius of your micro-ducts?
There is a simple formula:  Rmin=10x OD
If you have micro-duct 10mm, your Rmin=100mm
This limit is safe enough even for our DB version micro-ducts and installation in low temperatures.

2) What micro-duct combinations can be preinstalled in the main duct?
DuraPack product offers you high flexibility of your network. You can combine almost any sizes and number of micro-ducts. There is simple and only rule which limits number and sizes of micro-ducts:
Sum (Micro-duct OD) <=DuctID -4mm
Example: DuraPack 40/34 + 7x10mm
DuctID = 34mm
Micro-ductOD = 10mm
Sum (Micro-duct OD) diagonal = 3x10mm = 30mm
30mm <= 34-4

3) Can I get Declaration of Conformity for your products?

In terms of the Czech law no. 22/1997 SB., RESP. Č. 71/2000SB., telecom ducts and accessories do not come under the legal force of this law. Therefore Declaration of Conformity cannot be issued.

Anyway, Duraline CT guarantee high quality of all our products and we can issue our internal quality certificates when required.