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Don'’t let diesel issues bug your critical power

Fri, 02/01/2013 - 17:36 -- Ruth Williams

For many years, the diesel back-up generator has been a symbol of reliability for data centres, providing the emergency power to keep servers online during utility power outages. Standard data centre design includes an uninterruptible power supply (UPS), which can keep systems running during a mains power cut.

However, equipment will only stay online for the life of the battery in the UPS. For back-up power during an extended outage, a standby generator is the only viable choice. The most important consideration for these environments is to ensure that back-up power is constantly available.

Many data centres invest in standby generators to ensure power, and therefore data, is not lost in the event of a power failure.  With any luck, these machines will last for months, years, or even decades without the need to be used - however, when and if the time comes, it is critical to ensure  they will be fit for purpose.

To ensure this does not happen, many data centre teams and managers will have robust testing and maintenance procedures in place to test the generators, but many neglect to consider a very vital component – the diesel fuel that powers these machines. The contamination of which, can cause generators to fail and millions of pounds of data to be compromised or lost.

With generators sitting stagnant for so long, there is a very real risk that the fuel they run off can become contaminated, so if the machine does ever have to be used in the event of a power failure, it may not do the job it is there to do.

Fuel contamination can come from a number of sources and can include water, acids, resins and gums – all capable of blocking filters. Even something as simple as rainwater getting in to a fuel tank can cause costly damage to equipment, a lengthy cleaning process, and, most worryingly, the failure of a generator that is meant to ensure data is kept secure.

Biodiesel legislation loosens protection

One of the biggest issues in this era of more environmentally friendly bio-diesel fuels is ‘diesel bug’ – a fungus that grows in diesel that can potentially be fatal to the working of generators.

Prior to 2011 legislation that changed the make-up of diesel fuel, high sulphur levels in diesel managed to kill off most of the fungus and bugs, that grow as a result of water contamination, but with the introduction of new legislation on reduced sulphur levels, this 'protection' is no longer there. The bio-diesel blends now widely used for generators are more hydroscopic than old petro-diesel products, meaning it naturally absorbs more water from the atmosphere.

This water contamination means that diesel bug is able to thrive – the use of plant and animal matter used to produce these fuels provides ideal nutrition to the microbes, which can all lead to fuel becoming compromised.


The presence of diesel bug in fuel can lead to failures as the biomass they produce can cause blockages of engine filters. This is due to the advent of improved technology, meaning that diesel engine fuel systems now have tighter tolerances and are therefore susceptible to abrasions and blockages, which cause generators to fail.

If diesel bug is detected in fuel, it can be eradicated with the use of a broad spectrum biocide, which acts as an effective antibacterial and antifungal agent to kill the microbes present. However, this will not prevent one of the worst case scenarios from the arrival of diesel bug, commonly known as ‘bio-film’ – a layer of microbes that spreads across the inside of the fuel tank itself as a result of spores released from the fungus in the fuel.

These bio-films then release acid which can corrode fuel tanks, engines and pipes, causing irreparable damage. Even if bio-film is caught before this point, treatment can involve a tank cleaning process, although this can be achieved without removal of the fuel from the tank.

Prevention is better than cure

However, there are a number of ways to overcome these issues, and, as with many problems, prevention is better than cure. The key to maintaining fuel quality and preventing fuel contamination problems, therefore avoiding expensive engine damage, equipment downtime and data loss, is adopting a holistic approach to fuel management and taking care of generator diesel fuel.

The first step towards this is to establish a regular fuel maintenance programme, managed by the generator user with help from companies such as ours, to ensure water and dirt are removed from storage tanks. This will greatly reduce the risk of diesel bug and other detritus that causes breakdowns.

This should include a comprehensive a fuel monitoring programme whereby samples are taken at regular intervals to monitor the condition of fuel - these can then be tested for any impairments or issues, which can then be tackled accordingly before any serious problems are caused. If the beginnings of any issues are identified at this point, simply using fuel additives can be enough to nip the problem in the bud.

However, one of the most important investments you can make to truly ensure that you will have back-up power when you need it most are fuel polishing products. Designed to preserve the quality of stored diesel fuel, they constantly re-circulate fuel through a series of filtration stages removing water and solid particle contamination.


Fuel polishing system from IPU

To ensure ease of use for users, these can be made to function automatically, although they should be checked at regular intervals. What this fuel polishing product therefore does is ensure that fuel is kept primed for use when you may need it, reducing the risk of unpredictable failure of critical diesel driven equipment.

With a worldwide shift towards the use of more sustainable or ‘greener’ fuels such as biodiesel, there arrives a raft of new issues for those reliant on generators to keep their intellectual property safe. The serious compromise of fuel can not only cause engine failure, but it can also lead to the need to dispose of contaminated fuel, which defeats the object of switching to greener practices.

Simple tasks undertaken to protect the diesel in generators can not only avoid this, but will also protect the data that you have been entrusted to manage. As a bare minimum we recommend the use of fuel polishing and additives for stored fuel, backed up by the introduction of robust fuel management and testing procedures.

While often overlooked, these small procedures, which are surprisingly time and cost effective, can mean the difference between keeping a data centre safe and a potentially catastrophic loss of power.