No escaping the smoking hot change to legislation
Reliably and effectively extracting smoke during a fire is a critical design element for commercial ventilation systems. However, there is often a conflict between the tolerances required in the manufacture of high temperature fans and complying with the ever-increasing levels of fan and motor efficiencies. Yan Evans, Vice President for Fläkt Woods UK and Ireland, discusses these issues.
The fan industry has been on a rapid conveyor belt of development over the last decade, ever since the European Council adopted highly ambitious energy and climate change objectives. The well-renowned ’20-20-20’ targets are having a profound effect on the commercial ventilation industry, and the business of moving air from A-B is now overflowing with tough targets for specific fan powers, motor efficiencies, watts per litre per second and fan motor efficiency grades.
The headline figures surrounding the changes have been a direct result of EU Legislation and, more specifically, Regulation (EC) No. 640/2009. This requires motors to not have efficiencies lower than IE2 level and, from January 2015, motors with a rated output of 7.5kW to 375kW will not be less efficient than the IE3 level, or must meet the IE2 level when used in conjunction with a VSD (variable speed drive). In addition, Regulation (EU) No. 327/2011 applies to any fan with input power between 125W to 500kW, regardless of whether it is integrated with other equipment. Subsequently, since January 2013, fans have been subject to minimum efficiency requirements and these levels are set to increase substantially from January 2015.
Smoke extract fans
A key feature of any fan in a high temperature application is higher running clearances. These are designed to allow for the different expansion rates of the blade and housing materials under the influences of heat. Of course, higher running clearances cause a dramatic reduction in efficiencies (often up to 20%) compared to standard units. Consequently, Regulation (EU) No. 327/2011 for fans states that dedicated smoke extract equipment is exempt from the efficiency requirements, as they are only designed to be used in emergency conditions or when the system is being tested.
However, in more recent years, the integration of dual purpose units has become more prevalent in the UK. These use variable speed drives for day-to-day running and air extraction, as well as being used for smoke extraction in the event of a fire. This dual purpose application has grown in popularity for a number of reasons, not least of all for the reduced installation and maintenance costs. But, unlike dedicated fire smoke extract fans, dual purpose units are not exempt from Regulation (EU) No. 327/2011 and, as a consequence, need to comply with far stricter efficiency targets – albeit at slightly reduced levels to allow for the higher running clearances.
Tightened 2015 Regulations
The need to comply with the EU Regulations is about to become an even tougher task for dual purpose units, with the second tier of improved fan efficiencies due to be introduced in January 2015. This will require dual purpose units to meet new reduced nominal fan efficiencies increased from 50% to 58%, as well as comply with a lowering of the allowance for fire/smoke applications from 10% to 5%.
In effect, this represents a 22% hike in efficiency levels, which is going to have a significant impact on the market, not least of all with the number of dual purpose fans available. So, for projects beyond January 2015, it leaves building services engineers with two options. Firstly, they can decide to design-in fans that are only used for fire smoke extract and comply with the regulations. This would allow the remaining units to be optimised for efficiencies for day-to-day use, and keep running costs to a minimum. Alternatively, it may still be possible to obtain a dual use fan, although the range available will be less extensive, acknowledging and accepting that their efficiencies will be reduced. Also, larger fans may have to be used due to the limited range.
Of course, there are ways to mitigate the reduced efficiencies from dual purpose units and some manufacturers, such as Fläkt Woods, are already ahead of the legislation, designing new fan equipment incorporating ever more efficient blades. Alternatively, manufacturers may choose to use premium efficiency motors, or possibly combine improved aerodynamic fan designs with enhanced motor performance.
Every so often, the EU Commission reviews the regulations to assess the relevance, effectiveness, efficiency and added-value of the current European Directives. This is a requirement under Article 21 of the Ecodesign Directive and, in its April 2012 report, it highlighted that market surveillance and enforcement was an area of concern. It stated that this area posed “a threat to the credibility of the legislative framework” and was “undermining the efforts of industry.” As a result, the building services industry can expect this to become more of a priority over the next few years, especially with a step change in efficiency targets due in 2015.
Smoke extract units are likely to be under the spotlight more than most, with their usage for day-to-day ventilation a significant area of concern, which will be subject to close, ongoing monitoring and scrutiny. Market surveillance in the UK is being implemented by the NMO (National Measurement Office). And, based on their activities in policing other ErPs (Energy Related Product Directives) with revised legislation, anyone supplying or putting into service non-compliant equipment will eventually be brought to account.
Without doubt, the targets presented to the commercial ventilation industry are helping to drive efficiencies and, in doing so, reducing the carbon emissions associated with equipment operation, while also challenging manufacturers to push the boundaries of product design. However, specifiers and installers of this type of equipment must not assume the installation complies with the new regulations. And, in some instances, it might be worthwhile rethinking the approach to a fire smoke extract system, especially if it means reverting to dedicated separate fans rather than dual purpose units. After all, incorporating dedicated units can provide the best long term approach to optimising energy efficiency, which is the whole ethos of legislative changes – and will remain so for some years to come.
For more information please visit www.flaktwoods.co.uk
Published August 2014