Effective ventilation is now essential for maintaining indoor air quality and comfort for staff in commercial kitchens, and efficient fans are a must for meeting these regulations and keeping fuel costs down. David Cook, Product Marketing Manager – Non-Residential at Vent-Axia, explains how all this is affecting fan specification:
What’s cooking? Amendments to Part L of the Building Regulations, which came into effect last year, have had a significant effect on the catering industry. With an uplift in efficiency standards of 9% for non-domestic buildings, this has meant big changes for commercial kitchens. They are estimated to be 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. Energy efficiency is firmly on the agenda.
Add to this uncertain energy prices, which are continually fluctuating, and for kitchen operators it makes good sense to save energy by upgrading old inefficient ventilation. This offers a simple and cost effective way to help kitchen operators save energy and money as well as lowering carbon emissions.
A shake-up…
The Non-Domestic Building Services Compliance Guide, published in November 2013 to accompany Part L, has shaken up kitchen fan specification. Within the Guide, the maximum Specific Fan Power (SFP) in new and existing buildings for kitchen extract systems (fan remote from zone with grease filter) is listed as 1.0W/l/s.
This marked a significant step change for kitchen extract fans which previously, because of the higher pressures involved with kitchen extract, were often ignored within the Building Regulations - being perceived as a process rather than ventilation.
Most extract fans of this type struggle to meet this specific fan power requirement, meaning that upgrading to new energy efficient kitchen fans not only requires an investment in a new fan but a new fan technology.
Luckily ventilation manufacturers have been working hard to improve commercial kitchen fan efficiency and there is now technology on the market ready to meet the needs of the Building Services Compliance Guide. For instance, Vent-Axia’s innovative EKF Kitchen Box Fan range comfortably meets the 1.0W/l/s SFP set out in the Guide and is fully compliant with ERP2015.
External rotor motors run cooler and cleaner
To achieve a low SFP, this type of fan 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 clever 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; up to 120°C continuous in duct temperature.
Additional safety features ensure that if the temperature goes beyond this maximum and the fan’s motor becomes hot, it will slow down to prevent damage to the electronics. EC motors also have the advantage of a longer life than the AC equivalent as their high efficiency means less stress and wear.
Advanced aerodynamics and control
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 ventilating resulting in wasted energy.
In conjunction with the EC motors these features reduce the Kitchen Box Fan’s energy and running costs by up to 44% when compared to AC motor fans with a transformer speed control. This means kitchen operators can expect a return on the extra investment required to capitalise on this new technology in as little as 12 months.
Plus installation flexibility
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 kitchens fans are flexible to install as well as offering reduced running costs and high energy efficiency.
For example, the 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 with no loss of performance. This means that one unit can be used for almost any duct installation arrangement, internal or external.
Avoid fire risk - clean it as planned
This is all good news for commercial kitchens. However, to ensure the best performance from a kitchen fan, it is essential that kitchen operators put in place a planned maintenance regime.
It is estimated that more than 80% of kitchen extract ducts are never cleaned. This can have an adverse effect on fan efficiency; it can also affect kitchen insurance. Kitchen operators now have a legal duty under Health and 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 and the potential damage that this can cause to the motor.
In the current financial climate, updating a kitchen fan might not be the first thing a kitchen operator thinks of. However, with this new breed of energy efficient kitchen fan on the market it is now possible to replace old fans easily and economically, while meeting both the Compliance Guide and ERP15.
By upgrading kitchen ventilation, 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 more importantly ensure a healthy working environment.