These days there is hardly a place left where one does not come into contact with some form of radio waves.
Whether clock radios, temperature measuring stations, remote controls for various electronic devices or the German’s dearest toy, the mobile phone; for the most part, all devices send and/or receive their signal via radio waves and work within an exact frequency range in order to carry out their function – unaffected by other sources – in an as trouble-free way as possible. A mutual influencing must be excluded especially when it is a question of security, if for example police radio and radio wireless fire detection technology are practiced in the immediate neighborhood, as is the case at the Wuppertal police headquarters in Germany.
The Wuppertal District Police Department encompasses the three Bergische cities of Wuppertal, Remscheid and Solingen and is one of the largest of its kind with about 640,000 inhabitants in the Dusseldorf administrative district. The so-called police detainment facility (PDF) – which serves as a secured are – is also located on the valley axis of the Bergische metropolis behind the main building of the police headquarters. In addition to two larger holding cells and 16 normal cells, there are six drying-out cells in the six-storey building which, because of their nature (completely tiled and only 10cm high plank beds as well as sunken toilets) are suited for holding heavily inebriated people. All cells are equipped with a call system with which an inmate’s request is indicated to the guards if necessary – outside of the regular cell inspections. PDF personnel require calmness, intuition, and a high degree of experience in people skills. Of course safety must not be forgotten. Even in the seemingly soberly and coldly tiled cells, the risk of fire cannot be excluded.
Planning and commissioning via the BLB
The Bau- und Liegenschaftsbetrieb Nordrhein-Westfalen (BLB North Rhine – Westphalia), landlords of the premises and thus responsible for the building security, contracted the installation specialist IGS Industrielle Gefahrenmeldesysteme (located in Hagen) for the installation of the fire detector technical facilities after the previous detailed planning. Having many years of experience in the field, this enterprise is a partner of ESSER and uses its market leading products. A smooth handling of this task could be guaranteed within short time under the project management of BLB’s Frank Enselmann.
Wireless detection technology preferred in cells
Corresponding fire detectors were installed both in the single cells as well as in the holding cells, which can hold up to 25 persons. An adequate supply of fresh air is indeed provided and the corresponding air outlet is also ensured; however, a fire alarm system should additionally guarantee a necessary amount of safety.
Installation of the smoke detectors in the custody cells deviates from part 2 of the DIN VDE 0833 in that, due to operational reasons, the detectors were installed sunken into the ceiling. In order to keep the ceiling faces flush core drilling was necessary so a structural engineer had to be consulted. Extensive smoke test were carried out in order to examine this unconventional positioning of the detectors. It was determined here that early fire detection is not affected as long as no further protective covering is installed. Any covering with protection cage led to failure of early fire detection and was thus not permissible. Due to building-technical factors, the persons responsible decided in favor of the installation of the ireless model. 31 point-type automatic wireless smoke detectors were installed via a total of 5 wireless transponders where in each case one transponder is intended per floor and ensures the grouping and forwarding to the IQ8Control fire detector control panel. Further components of the fire alarm system: 75 O²T automatic detectors, one automatic fixed heat detector as well as 15 manual call points and the innovative IQ8Alarm speech alarm, all which guarantee a systematic evacuation where necessary. All components are connected to the control panel via four rings.
Measurement results evoke enthusiasm
The beginning of the construction had been fixed for April 2006. There was a lot of time pressure, as testing was scheduled to occur only a few weeks later, directly following the construction phase. During a visit to the site on the 7th December 2005, the first test was already passed with flying colors. Among those present were Jürgen Trapp, the technical director of IGS, Detlef Tubies, the technical sales consultant of the manufacturing firm Novar (ESSER by Honeywell), as well as the police in charge. The decisive question to be addressed was whether the police radio and the fire alarm system wireless detectors would mutually influence each other. The Central Police Technical Services of North Rhine-Westphalia were commissioned to carry out corresponding measurements for this purpose. The result was more than satisfactory for police senior commissioner Edmund Kamrau of the BOS radio monitoring/radio intelligence (security-related German authorities and organizations) as well as for all other participants – actually they were really quite enthusiastic. One reason for this enthusiasm was the technical component that enabled the wireless detectors to manage with the extremely low transmission power of only 10 MW.
By toggling to 5 and / or 20 channels in both planned frequency bands, a solidly high transmission quality can be maintained, even in alternating environmental conditions, for example when the police radio suddenly becomes active.
Not only where the radio components checked inside out before the initial start-up, the complete fire alarm system had to be approved by a specialist on site. Certified engineer Burkhard Imken, a state-certified and VdS-standard expert, summarized the result in his report, short but sweet: No defects were found. No objection to installation start-up. The installation is reliable and effective including its respective fire precautions.
