What is Importance of Duct Spacer in Optical Fiber Network

Importance of Duct Spacer in Optical Fiber Network : 

Today I will discuss about duct spacer in this article. Often people ignore about duct spacer during the installation of optical network construction and think that it is very small part of optical network construction. But it is not so, duct spacer is also very important in optical network construction, which we will try to know about today.

Duct spacer in compliance with specification shall be used in the underground outside plant of the telecommunications network. Duct spacers are used to position ducts and to support the ducts while maintaining adequate separation in preparation for subsequent concrete encasement or direct burial with appropriate sand embedding.


Duct spacer used in optical fiber network
Duct Spacer

What is a duct spacer and why use it

It is true that the duct spacer is not a very big topic in itself, on which a long wide article should be written. We will discuss what it importance and why it is used in optical network construction.

As I have already written above that duct spacer are used to position ducts and to support the ducts and provide the adequate separation between the ducts. The duct spacer are preferably be delivered in basic sizes that can be joined together to support any number of ducts.

The duct spacer supplied according to telecom industry specification shall be capable of withstanding the typical service conditions of local area for a period of approx twenty years without detriment to the operation and maintenance characteristics.

Design Requirement of Duct Spacer

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The design of the duct spacer shall allow for ease of system installation and the spacer shall be interchangeable. The duct spacer can be delivered as single cradle and double cradle models.

The duct spacer shall preferably be delivered in basic sizes that can be joined together to support any number of ducts.

Duct spacer shall be designed, manufactured and packaged so that the physical, transmission and operation and maintenance characteristics shall not degrade when exposed to the environmental conditions of local area during storage.


The cradles of the duct spacer shall be at least 30 mm wide and have a diameter of 110 mm to accommodate PVC-ducts. The duct spacer shall be suitable for multiple row and multiple column placement. They must be interconnect able, or at fast have mating surfaces which can be easily matched to adjacent spacers.

The duct spacer shall provide a uniform separation of the ducts within the formation in the trench (both vertically and horizontally). The duct spacer shall be of a heavy duty design and construction such that they will be able to withstand a static, equally distributed load of 150 kg, once installed, without being crushed or cracked.

The duct spacer shall be designed to limit slip between themselves or the ducts in the formation while the formation is being assembled, or while the concrete encasement is being poured. The duct spacer shall be easily assembled.

RAW MATERIAL : The duct spacer shall be made of virgin unplasticized, polyvinyl chloride (PVC), or a suitable alternative.

TENSILE STRENGTH (TA) : The PVC shall have a minimum tensile strength of 50 MPa. All materials shall be new and shall not contain fillers, plasticizers, or additives which may react harmfully with PVC ducts. 

No constituent material shall be used which will adversely affect the long term mechanical strength of the PVC. All constituents shall be uniformly and fully dispersed.

WATER ABSORPTION : The average water absorption shall be less than 0.1 % by weight, with no result being higher than 0.2 %. 

You can also READ Duct Fitting and Accessories in Optical Network

Packing and Marking of Spacer

Duct spacers shall be packed in boxes sufficient for protecting from ultraviolet radiation for 1 year. The boxes shall be suitable to protect the spacers from damage shipping by land or sea, and during storage.

The maximum packed weight of each box shall be 25 Kg. Each package shall be marked  with the information in English.

Last Word

I hope you will be satisfied with this article and it would have helped you a lot to understand the duct spacer. Duct spacer are especially used where many ducts are laid together. It is also used exclusively in FTTH networks. If you are satisfied with the information given by technopediasite, then please like and share. Stay connected with us for such type of information.

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