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High-temp fan-drives will make buildings safer during fires
Published:  21 October, 2019

The fan-maker Fläkt Woods has collaborated with Danfoss to develop and certify a range of high-temperature fan/VSD packages that comply with the EN12101-3:2015 standard, making it easier to provide efficient, reliable smoke control in buildings during fires. The certified fan/VSD packages are the first of their type to reach the market.

The EN12101-3:2015 standard, which came into effect in 2017, offers three options for controlling fans that must continue to operate during fires. These are:

♦  to bypass the VSD controlling the fan motor during fires;

♦  to derate the fan motor by 20% and fit a voltage waveform filter; or

♦  to use a tested and certified high-temperature fan/VSD package.

Fläkt Woods believes that, for most applications, the third option offers significant benefits in terms of increasing the safety of building occupants.

The combined axial fans and VSDs have been tested and certified for their ability to continue operating during fires

“Bypassing the VSD during a fire event means that the fan must run at full speed, which makes it difficult for designers to implement their required smoke control and extraction strategies,” explains Fläkt Woods’ axial fans product manager, Andy Cardy. “And using a non-certified fan/VSD package means fitting an oversized motor and an expensive filter that may well cost more than the VSD. With all of this in mind, we decided to go ahead with developing a tested and certified fan/VSD solution.”

Engineers from Fläkt Woods and Danfoss spent more than two years investigating the possible options for controlling fans during fires. The package they eventually developed uses Danfoss VSDs with operating parameters specifically selected for the application. The finalised products were subjected to rigorous third-party testing at BSRIA – as required by EN12101-3:2015 – which they passed.

“We see this as an important breakthrough in building safety because knowing that they will retain full control over fans during a fire event gives designers many more options for efficient and effective smoke control,” says Cardy.