Comparison of the old and new SOS emergency alarms. Old SOS box from 1987.
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Within the Murg-Walenstadt project, cablex is responsible for maintaining the existing optical fibre infrastructure, and is simultaneously carrying out the construction of the new optical fibre infrastructure. In
addition, it is planning the entire fibre management.
The repair work of the tunnel is being carried out on behalf of the Federal Roads Authority (ASTRA) on the section of the A3 between Murg and Walenstadt, which among other things also includes increasing the safety in five tunnels. To keep the impact on the traffic as low as possible, the Walenstadt north tunnels in the direction of Murg are initially being rehabilitated at night. Rehabilitation of the south tunnels in the direction of Chur will begin in 2020. cablex’s work pertains to cabling the SOS alarm boxes along the road and in the cross-passages, as well as planning, ordering, equipping and installing the equipment cabinets related to the optical fibre infrastructure.
One worker has to install two SOS alarm boxes per shift. Altogether, 4,236 splices will be carried out on the north side of the tunnel.
During the course of the tunnel rehabilitation, a total of 150 new SOS alarm boxes will be installed and cabled.
cablex will install the optical fibre system in the alarm boxes to ensure the data exchange works for all components including the emergency telephone system, fire alarm system, energy monitoring and ventilation sensor system, among others. The tasks of cablex here are splicing, measuring, testing and putting into operation (patching).
The work done by cablex will ensure both the data exchange between the devices in the SOS alarm boxes as well as with the outside world. This will be handled via optical fibre. The advantage of glass fibre is that it can be used to communicate over long distances without any problems and it is thinner and more cost-effective.
Installation of the sub-distribution in the cross-passages is somewhat more complex and extensive. Here, the connections in the cable end box are fully connected. This means that there are twice as many optical fibre connections to perform in these cabinets than in the emergency telephones beside the roadway. The additional connections are required for radio, police radio and for transmission of the SOS signals.
The cablex team has a maximum of two weeks per tunnel for the installation. Since the tunnel is in operation during the day and can only be blocked off for work between 8.00 p.m. and 5.00 a.m., there is a great deal of time pressure. The workers have to clock out via the construction site exit by 4.30 a.m. so that the tunnel can be opened for traffic once again. One worker has to install two SOS alarm boxes per shift. Altogether, 4,236 splices will be carried out on the north side of the tunnel.
cablex has an engineering mandate in this tunnel. This means that the creation of the plans and allocation is handled by cablex. cablex will develop the plan of the optical fibre infrastructure from the plan of the engineering office.
All the splices and installations in the central control rooms will be carried out by cablex. Hence, cablex is responsible for the supply of the third-party cabinets and ensures that all connections are “active”, and which signal provided to which connector is clearly recognisable. Altogether, twelve equipment cabins were installed and connected by cablex in nine central control rooms. However, the plug-in mounts had to be installed by the outside companies themselves because of the division of responsibilities.
Installation according to requirements
A model will be made for each part of the installations that are to be carried out: a model SOS alarm box, a model sub-distribution cross-passage, and a model equipment cabinet. They will be accepted by the project authors and ASTRA. A template will be created from the acceptance of the model installation and passed on to the installers. This ensures that the requirements will be applied to all further installations.
The measurement results will be documented after the measurement of the connections. The analysis of the raw data of the measurements will be prepared by software called the Fibre Cloud. The final documentation will be generated from this data. There will be one document per connection. The precise analysis of one document takes two to three hours of work. In addition, cablex will perform a self-check. A check-list for the SOS alarms and the cross-passages will be developed for this purpose to be able to ensure and keep track of the quality of the work.
ASTRA has clear requirements for use of the devices in order to ensure the quality of the splices. The devices may not perform more than 1500 splices with the same tips. Since the splicing devices have no counter, the number of splices must be carefully documented in order to guarantee the customer the required quality.
Each splicing device is assigned to one person. This assignment is entered in the equipment management system. The service certificate is also stored there. In this way, the customer can be informed on request at any time about which splicing device was used at which location.
Delimitation of responsibility
cablex does not pull the cable itself in this project. For this reason, the definition of the areas of responsibility for the interface between the cable pulling and installation of the optical fibre infrastructure is extremely important. The particular challenge is to maintain these defined interfaces across the entire project and the multitude of installed cables.