Diesel-powered fire pumps
Published: 12 May, 2008
Jeanne van Buren, senior specialist in industrial safety at the Centre for Industrial Safety for the Regional Rotterdam-Rijnmond Fire Services in the Netherlands, takes a closer look at diesel-powered fire pumps, where all is not as it seems.
All over the world diesel powered fire pumps are used to independently secure the supply of fire water. Nevertheless many users do not know that these diesel engines were, in fact, originally designed to be used only in trucks.
Manufacturers of these engines have made many adjustments to these engines over the last decades necessary to meet stringent environmental emission criteria, technical and safety requirements. The “get me home“ function – where with considerable reduced power an engine that due to a malfunction cannot operate properly is still able to cover the legally required minimum distance of 80 km – is just one example of the latter. These same engines are often used for auxiliary power supply too.
Diesel engines will nowadays be fitted with computer-operated Electronic Control Units (ECU) to comply with legal requirements. In addition the diesel fuel for these engines will have to meet specific quality criteria that can only be matched by the diesel bought at petrol stations. Without this fuel, the engine will not operate at all or the reliability of the engine cannot be guaranteed.
The settings in the computer – which are only relevant if the engine is used on a truck – can only be accessed by a supplier’s maintenance engineer. This means the computer becomes a black box that may or may not – during a fire – pose an undetected problem because the engineer may reset the setting to the original values during maintenance without the knowledge of the user. This can have many consequences, and here is an example to give you an idea.
At some stage during a fire the diesel engine does not meet the pre-programmed emission standards or the engine gets a little bit hotter than would be expected. The computer will then automatically adjust the output of the diesel engine, resulting in a reduction of the flow and pressure of the fire water. This is an absolute nightmare for all involved.
Many companies that buy these engines for their fire water supply pumps do not know that the performance standards of these truck engines will deviate completely from the performance standards that are relevant for fire pumps.
So what can operators do with this knowledge? Firstly, all the computer programs in the ECM of the diesel engine that powers a fire pump that detect that the emissions of the engine are not meeting the preprogrammed standards and/or can interfere with the operation of the engine when malfunctions of the engine are detected, should be disabled.
Secondly, a report should be presented on delivery of the engine stating that these functions have been disabled and that the engine was tested under these conditions.
Each time the maintenance engineer visits he should make a note in the log of the engine saying that he has not reset these settings during maintenance.
The minimum requirements for the electrical power supply of the ECM should be as follows:
• 1 battery set A
• 1 battery set B
• 1 battery charger A
• 1 battery charger B
• 1 dynamo of the diesel engine
Each of these power supplies should be linked to an alarm that will activate when a fault is detected, and they should also be protected against sudden high voltage and polarisation.
Any transmitter connected to the ECM that could influence the output and/or number of revolutions of the engine should have an identical spare transmitter to automatically function in case of malfunction of the primary transmitter/pickup.
Where a diesel engine is fitted with sequential cooling systems, these cooling systems should be able to handle the system’s maximum pump pressure. The method and requirements for maintaining these cooling systems should be described separately in the maintenance contract as well as the maintenance protocol.
The quality of the fuel of these diesel engines should meet the requirements of standard EN 590, “Automotive fuels: diesel requirements and test methods”.
About the author
Jeanne van Buren is senior specialist in industrial safety at the Centre for Industrial Safety for the Regional Rotterdam-Rijnmond Fire Services in the Netherlands. Jeanne started as a firefighter when she worked at Delft University and joined the onsite fire service. She became the first female HAZMAT officer of the Rotterdam-Rijnmond regional emergency response organisation. She successfully qualified for the Dutch equivalent of a BA in Process Engineering, Chemical Engineering, Applied Chemistry and Environmental Engineering and finished an MSc degree in Environmental Quality Management at De Montfort University and one in Risk Crisis and Disaster Management at Leicester University. Since then she has started the research into integrated fire safety during the whole life cycle at SEVESO sites for a PhD at Delft University.