Heating and Ventilating


A step change in kitchen fans

For professional kitchens energy efficient ventilation is essential to both maintain good indoor air quality and comfort for staff as well as keeping fuel costs down. However, David Cook of Vent Axia says changes to Building Regulations are set to affect fan specification in kitchens
WITH 2013 seeing the amendments to Part L of the Building Regulations, many in the HVAC sector were wondering how the changes would affect ventilation. After a long wait for the regulations to be published many were underwhelmed by the final document.

However, the new Part L does include an uplift in efficiency standards of nine per cent for non-domestic buildings, putting energy efficiency firmly on the agenda. For the catering industry this is significant since estimates indicate it is one of the largest energy consumers in the commercial market, using approximately two and a half times more energy per square metre of floor area than the average commercial building. Add to this energy prices which are continually escalating and for kitchen operators it makes good sense to save energy through investing in energy efficient equipment.

Upgrading old inefficient ventilation can offer a simple and cost effective way to help kitchen operators save energy and money as well as lowering carbon emissions. Although when it comes to specifying new kitchen fans the hospitality industry may not be aware there are changes ahead coming into effect in April 2014.

The Non-Domestic Building Services Compliance Guide, published in November to accompany Part L, looks set to shake up kitchen fan specification. Within the Guide a maximum Specific Fan Power (SFP) in air distribution systems in new and existing buildings for kitchen extract (fan remote from zone with grease filter) is listed as 1.0W/l/s. This marks a significant step change for kitchen extract fans which often need to accommodate high air changes, elevated temperatures and significant levels of grease, the latter that often requires filters to protect the fans.

Most extract fans, of this type, currently installed in commercial kitchens would not meet this specific fan power. This means that upgrading to new energy efficient kitchen fans not only requires an investment in a new fan but a new fan technology. But with budgets tight, investing in equipment might appear a tall order for stretched businesses especially if new state-of-the art technology is needed to meet the compliance document.

Luckily, ventilation manufacturers have been working hard to improve commercial kitchen fan efficiency and there is already new technology on the market ready to meet the needs of the Building Services Compliance Guide. For instance, Vent-Axia's EKF Kitchen Box Fan Range comfortably meets the 1.0W/l/s SFP set out in the Guide and is fully compliant with ERP2015.

Not only that, but as well as a low SFP, this type of fan also features energy efficient EC motors. This marks a significant development for kitchen fan evolution since typically kitchen fans use AC motors to cope with the elevated temperatures experienced in commercial kitchens.

However, the design of this new breed of kitchen fan features an external rotor motor with a shaft out design to drive the impeller. This means that the motor is positioned outside the grease laden airstream which keeps it cooler and cleaner allowing the hospitality sector to benefit from the energy efficiency of an EC motor in a hot kitchen environment.

This new kitchen fan can operate reliably in aggressive kitchen environments up to 120°C. An extra safety feature of the fan also ensures that in elevated temperatures beyond the design maximum if the fan's motor becomes hot it will slow down to prevent damage to the electronics. Meanwhile, the high efficiency EC motor design results in less stress on the motor and lower wear, thus extending the life for the motor when compared to AC alternatives.

To further improve efficiency these kitchen fans also feature backward curved impellers and an integral potentiometer that provides full manual speed control ensuring that the system is not over ventilated resulting in wasted energy. In conjunction with the EC motors these features reduce the Kitchen Box Fan's energy and running costs up to 44 per cent when compared to AC motor fans with a transformer speed control. Kitchen operators can experience a return on the extra investment required to capitalise on this new technology, in as little as 12 months.

Today the requirements placed on kitchen ventilation systems are tighter than ever before with catering businesses demanding higher filtration levels to cope with the grease laden environment and longer duct runs to aid installation. With restricted space kitchen installations can often prove tricky. With this in mind manufacturers have ensured these new kitchen fans are flexible to install as well as offering reduced running costs, and high energy efficiency. For example, Vent-Axia's EKF Range is designed for internal or external mounting as standard, duct connections can be made in any direction, blowing straight through, or turning through 90°C with the ducts positioned either vertically, horizontally or both. This means one unit can be used for almost any duct installation arrangement, internal or external.

This is all good news for commercial kitchens, however to ensure the best performance from a kitchen fan it is essential kitchen operators put in place a planned maintenance regime to deal with the grease laden environment. It is estimated that more than 80 per cent of kitchen extract ducts are never cleaned. This can have an adverse effect on fan efficiency. It can also affect kitchen insurance. Kitchen operators have a legal duty under health & safety regulations to assess fire risk in the ventilation system, in particular those created by excessive build-up of cooking oil deposits. If sufficient duty of care is not taken charges of corporate liability or manslaughter could be brought against the kitchen operator if a fire breaks out.

To help with this the latest kitchen fans include multiple access panels and an easily removable motor and impeller which facilitates easy cleaning of the system. Meanwhile, since the motor is positioned out of the airstream this minimises its exposure to dirt and grease, removing the need to steam clean the motor.

With this new breed of kitchen fan it is now possible to replace old fans easily and economically, while meeting both the Compliance Guide and ERP15. Operators can not only save money on energy bills but also provide better comfort for staff and use it as a chance to put in place a fan and ductwork maintenance regime that could both save money and ensure a healthy working environment.

//The author is the commercial and industrial product marketing manager at Vent-Axia//
1 December 2013


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