Defence Ljiljana Zlatanovic

15 maart 2017 | 12:30 - 15 maart 2017 | 13:30
plaats: TU Delft | Aula
door Secretariaat Sanitary Engineering

The effectiveness of automatic fire sprinkler systems has been proven over the decades of their application, with respect to the property damage, number of casualties and injured from fires.

Nevertheless, large application of sprinkler systems in the Netherlands is not feasible due to the operational requirements of the commercially available residential sprinklers, in terms of flow and pressure, 50-80 L/min and 0.7- 1.6 bar, respectively. These requirements cannot be assured at the house level in the Netherlands. A decade long discussion on fire flows, delivered through drinking water networks, have drawn fire fighters and drinking water companies together, exploring innovative approaches to improve public health and safety in homes.

The first part of this thesis addressed the innovative design of a sprinkler head that is efficient at low flows and pressures, and could be directly incorporated in domestic drinking water systems (DDWSs). A preliminary step towards the development of a low flow and low pressure fire sprinkler included assessment of the suppression potential of a droplet screen formed by a sprinkler under low flow and low pressure conditions. Applying different sprinkler configurations and various operational flow and pressure ranges, the experimental results showed that it is possible to obtain outstanding sprinkler efficiency under low flow and pressure ranges, as the sprinkler operating with a flow of 17 L/min might still deliver around 90% of the specific heat capacity of the sprinkler operating with a flow of 49.5 L/ min. Following these findings, TU Delft in collaboration with Bam Techniek, VSH Fitting, Brandweer Haaglanden has successfully developed a sprinkler head (“waterleidingsprinkler”) that is suitable for Dutch houses and is expected to be applied on a large scale in the coming years.

Once the first goal of the research was accomplished, a second step was taken to explore the influence of plumbing extension for sprinkler system accommodation on water quality because adding a sprinkler system to the DDWS must not jeopardize the quality of the drinking water. Two full-scale DDWSs, one resembling a conventional system and the other extended with the piping for incorporation of a residential sprinkler system, were built and run according to one year stochastic drinking water demand. Fresh and 10 hours stagnant water were sampled from two taps, kitchen and shower. Even though some differences in water quality were observed between the stagnant water samples from the shower taps in the conventional and extended systems, insignificant differences between all fresh water samples were found for all examined parameters, meaning that the tap flushing can restore the quality of the drinking water quality in DDWSs. It was concluded that the extension of the DWDS for residential fire sprinklers had limited effect on drinking water quality parameters, during the 14 months of the experimental study.

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