Tag Archives: sprinkler systems

Many fire protection systems are faulty

sprinkler

Approximately 70% of automatic fire alarm systems and more than 50% of sprinkler systems in Danish companies and public institutions are faulty when they are inspected. That is the result of an analysis conducted by the Danish Institute of Fire and Security Technology, DBI, on the basis of figures from 2015 and 2016.

DBI inspects fire protection systems once a year and finds many different types of faults in the process. A new analysis conducted by DBI shows that only a very small percentage of the faults are so critical that the systems have to be discarded. However, less critical faults can also be serious enough in themselves. For example, faults in automatic fire alarm systems can lead to false alarms and delays in raising the alert, while faults in sprinkler systems can result in a fire spreading to areas not protected by a sprinkler system much more ferociously.

– The faults seldom mean that a system fails completely in the event of a fire, but delays can have serious consequences and false alarms contribute to undermining users’ confidence in alarm systems, says Anders Frost-Jensen, Director of Infrastructure & Quality in DBI.

Errors in orientation plans
Around half of the faults are actually administrative errors, DBI’s analysis shows, and it is orientation plans of the building and the system in particular that are lagging behind.

– If the orientation plans are wrong, it could take the fire brigade quite a long time to find the right room or area when the alarm goes off. Time is the crucial factor when it comes to the development of a fire and the safety risk. And if you have forgotten to fit detectors in a room following a refurbishment, the fire will be detected much later than it should be, explains Anders Frost-Jensen.

Work pressure and increased complexity
The 70% is the highest number of faults and errors that DBI has recorded in its statistics up to now, and the figure has been rising sharply in recent years. However, a third of the faults can be classed as installation faults which, according to the DBI Director, are partly due to work pressure on the part of the installers and partly due to increased complexity in the buildings.

– Buildings are constructed differently nowadays and different systems often have to be integrated with one another. That makes it difficult to assess whether the systems have been installed correctly, says Anders Frost-Jensen.

Explosions in sprinkler system probably caused by hydrogen gas

Sprinklercentral-2

The development of flammable gases in the pipework is the probable cause of the explosions that occurred in two sprinkler systems, injuring several technical employees, back in 2014. A chemical reaction between zinc and water in the pipe system can easily form a flammable hydrogen gas that can lead to an explosion in certain situations. This is one of the conclusions in a new report published via Finance Norway.

In 2014, there were explosions in two different sprinkler systems in Denmark. The first occurred at the premises of the Danish company Movianto in Greve, where a service engineer was injured, even though the explosion actually moved out into the open air. And, shortly afterwards, in the department store Magasin in Lyngby north of Copenhagen, where an installation contractor was burned because an explosion occurred in a large pressure storage tank in a small room with the result that the explosion was particularly powerful. On both occasions, the sprinkler system ignited and exploded due to a flammable gas in the system following the draining of water.

A new technical report published via Finance Norway concludes that hydrogen can be formed due to a chemical reaction in the ‘wet’ zinc-coated pipe system. As zinc-coated pipe installations are often used in sprinkler systems in Denmark, the report’s conclusions constitute extremely important information – not least for those people who work with sprinkler systems.

– There was obviously a chemical reaction between the zinc and the water in the pipe, after which the hydrogen in the water was secreted and ignited by sparks created during the emptying of water in the sprinkler installation, explains Anders Frost-Jensen, Director in DBI.

Only in Scandinavia
Flemming Lindegaard, an inspector with the Danish Working Environment Authority, also points to a clear link between hydrogen in the pipe system and the explosion which occurred in Magasin. The secreted hydrogen has thus formed gas pockets and increased the pressure in the closed piping in the system. The gas escaped during operational and maintenance work, whereby the pipes were opened in order to discharge the water. In the open air, the gas mixed with the oxygen, reaching a critical concentration, which was then ignited by sparks from tools. This trio, consisting of a source of ignition, a flammable gas and oxygen, led to combustion which resulted in an explosion that was so powerful that, in the worst case scenario, can move concrete walls.

– We have, via our international work, made inquiries regarding experiences in the area throughout Europe. However, it is a phenomenon that we have only experienced in Scandinavia so far, says Anders Frost-Jensen, before elaborating:

– There can be several explanations as to how we are witnessing these explosions now and hearing about flames resulting from maintenance work. The fact is that within the last ten years we have been working with zinc-coated piping in sprinkler systems instead of black steel pipes, and the results from Norway show that the risk of an explosion is greater when zinc pipes are used. Moreover, it seems that it is possible to prove a link to the quality of the water in the area in which the installation is located, including the pH value of the water quality, because it could have helped increase the production of hydrogen in the pipe system, he explains.

Revision of sprinkler guidelines
In collaboration with a Standing Technical Committee, DBI now intends to incorporate the relevant conditions and experiences from Norway into the Danish sprinkler guidelines so that the risk of further accidents related to operational and maintenance work on sprinkler systems is minimised as far as possible.

– However, we are already able to make some recommendations and emphasise the importance of checking for abnormal increases in pressure in pipe systems and use non-sparking tools when emptying water from the system, says Anders Frost-Jensen.

In addition, the Danish Working Environment authority has issued a number of recommendations as to how work on sprinkler systems can be carried out safely. These include the use of gas detectors or explosimeters for measuring the concentration of hydrogen, recommending that no work is being carried out while the sprinkler system is being emptied, ensuring that there is good ventilation while the system is being emptied so that any hydrogen is removed from the site it is generated, and that electrical installations in the sprinkler room are installed correctly so that the generation of sparks is avoided.