Södertälje Hospital - a success story

Nexans is a supplier of alarms to Södertälje Hospital

Rescue services rejected the fire protection at Södertälje Hospital. Categori Data in Sundbyberg has now installed complete protection for which a significant proprtion of the of the cables were supplied by Nexans. A total of twelve thousand metres of cable has been laid to enable all rooms in the hospital to be covered by the alarm system.

Rescue services could not accept that only the escape routes were alarmed at the hospital and set requirements for alarms in every room, including halls, toilets and storage rooms. This meant that most of the vital parts of the system had to be replaced.

Old ionising detectors were replaced by optical detectors, large stretches of the wiring were replaced and the number of alarms with red and white flashlights and sirens was increased. In addition, the alarm centre was expanded with more output cards to enable it to handle all new alarm devices. The cables for the alrm system are hanging in red jackets and pipes, joined in a central network with a    ten-conductor, which then branches off to two-conductors out to detectors and alarm devices.

A large section of the cabling is the Nexans fireproof Alsecure that is able to withstand fire for at least 30 minutes. All alarm cables are halogen free and flame-retardant, which means that they do not spread toxic smoke or take the fire through the walls.

Twelve thousand metres of new cable

The new fire alarm system required twelve thousand metres of new cable, despite modern technology making it possible to connect more alarms to each cable loop and thereby reducing the need for cable. The cables of the alarm system are usually secured under the cable ladders that carry the hospital power supply and other telecommunications cables. Alternatively, they can be laid in a separate ducting channel. This is to prevent the cables to the fire alarm from being damaged when for example, new power lines are pulled or something else is done with the cables on the ladders.

Requirement for experience

Building a fire alarm system in a hospital is technically no more difficult than building one in another property. On the other hand, the location places demands on the experience of those who perform the job. They must know what a technical description means and have an understanding of the administrative regulations that frame what is and is not possible. The installer must also understand the rules of the property manager, as well as understand what has been ordered and be able to quickly identify and inform if there is anything that does not match the plans. It is very important to take extra care with detailed planning. Everything should be reviewed on site in advance to establish processes for how the work is to be carried out in practice.

Cables are better for fire alarms. Wireless systems require transmitters and receivers that go through walls and if there are two concrete walls present, it doesn't work. The smallest conversion for example, building or tearing down a partition, means that new entries have to be amde to the system. In addition, wireless information can be distrupted.