© Janosch Abel

Happy hemp thanks to perfect venti­la­tion

Since cannabis with THC content under one percent was legal­ized in Switzer­land, the sector has been booming. BioCan AG got in on the ground floor of hemp culti­va­tion. Thanks to good venti­la­tion, its harvest is better than that of its competi­tors.


Philipp Schen­nach and Jorma Lori look proudly over the fruits of their labor: several thou­sand hemp plants swaying back and forth in the arti­fi­cial wind and illu­mi­nated by 170 lamps simu­lating the sun. In about three weeks, the harvest can begin. And none too soon; demand for the plant is huge. Hemp truly has many func­tions. Its fibers can be used in textiles and even in the auto­mo­bile industry, and the compounds in its flowers relieve pain, relax muscles and stim­u­late the appetite, so the plant is gaining accep­tance in the medical commu­nity. And the oil from its seeds can even be used as fuel.

But the consump­tion of hemp is off limits in almost all coun­tries. However, in Switzer­land a deci­sion by the Federal Office of Public Health (FOPH) in 2016 really stirred up the market. The sale of hemp is now legal as long as the concen­tra­tion of the psychoac­tive substance tetrahy­dro­cannabinol, better known by its initials as THC, is under one percent. In this case, hemp counts as a tobacco substi­tute. Schen­nach and Lori have had lots to do since then. They work at BioCan AG, the first Swiss company permitted to produce and sell cannabis legally as a tobacco substi­tute.

BioCan AG

The founder of the company, which is head­quar­tered in Thayngen, Switzer­land, is Markus Walther, a pioneer in hemp produc­tion who was advo­cating its legal­iza­tion for sale as long ago as the 1990s. Through numerous hybridiza­tions, he was able to breed a hemp plant with a THC concen­tra­tion below one percent. When the Federal Office of Public Health gave its approval in 2016, he and his company got to work. In addi­tion to hemp for smoking, BioCan AG also supplies hemp oil and tablets.

The deci­sion by the FOPH was a huge oppor­tu­nity for Schen­nach and Lori. Lori, actu­ally a carpenter by trade, is one of the founders of BioCan AG. He is the facility manager for culti­va­tion at its site in Bassers­dorf. Schen­nach heard from an acquain­tance that the company was looking for investors. Since he had some savings to spare, he invested. “But soon I wanted to be involved in hemp culti­va­tion myself, so I got involved in the oper­a­tional side of the busi­ness.”

Schen­nach is actu­ally a trained brewer. “There is common ground with beer, because hops are also a member of the hemp family.” At BioCan AG, he took the posi­tion of tech­nical director for indoor produc­tion, one of three produc­tion methods along with green­houses and fields. “That way we spread the risks. Out in the fields, crop fail­ures can happen frequently. Indoors we’re inde­pen­dent of the seasons.”

Hemp likes it windy

Schen­nach and Lori approached their new task with enthu­siasm. In the indus­trial park in Bassers­dorf, a small commu­nity near Zurich, they rented two floors in an office building, a total of 3,000 square meters. Then they were able to begin designing their facility. A crucial compo­nent of their plan­ning was the venti­la­tion. “Good venti­la­tion is very impor­tant for the plants,” says Schen­nach. Hemp plants are actu­ally very unde­manding.

“Good venti­la­tion is very impor­tant for the plants.”

Philipp Schen­nach, BioCan AG

The valu­able part is the buds on the female plants; the bigger they are the better. But the stems have to be strong enough to bear the weight of the buds. In the wild, the wind strengthens the plants. “We try to simu­late nature as well as we can indoors, so there should always be a light breeze there. To do that, we need good tech­nology,” explains Lori.

Hemp back­ground

Cannabis is the scien­tific name for hemp. The valu­able part is the buds on the female plant, which are host to over 80 cannabi­noids and over 400 active substances. The most impor­tant cannabi­noids are the intox­i­cating tetrahy­dro­cannabinol (THC) and the non-intox­i­cating cannabidiol (CBD). Hemp with a THC content of less than one percent is also called CBD hemp. Medi­c­inal effects are attrib­uted to CBD. It’s impor­tant to keep the blos­soms from being fertil­ized by pollen, which would make them worth­less.

A constant breeze also inhibits the growth of mold and mildew in the humidity arising from the plants’ tran­spi­ra­tion. “We don’t need any pesti­cides at all.” One advan­tage of indoor produc­tion is that the growth period can be controlled. “Hemp is actu­ally an annual plant. In spring and summer, it puts all of its energy into growth. When the days get shorter in the fall, the plant knows it’s time to repro­duce and it forms flowers.

By control­ling the lighting, we can shorten this process and get up to six crops per year instead of just one.” But the lamps with 600 or 1000 watts each generate a lot of heat, so cooling is another impor­tant func­tion of the venti­la­tion system.

Plan­ning for the facility

With these ideas in mind, Schen­nach and Lori got to work on the design and began drawing up plans. They thought about how the fans had to be posi­tioned for optimum air flow and calcu­lated pres­sure losses and the required air perfor­mance. They did research in the Internet to find suit­able fans for their require­ments. When they saw the product video for the RadiPac centrifugal fan on the ebm-papst website, they knew: “That’s the one!” So Schen­nach got in touch with ebm-papst.

It was a some­what unusual inquiry for Daniel Schefer at ebm-papst in Switzer­land. “It’s not every day that our prod­ucts are used for hemp produc­tion.” During an on-site visit, Schen­nach explained to him that he was still looking for a solu­tion to generate air flow over the entire 30-meter length of the room. For that, he needed fans with high air throw.

“We have a facility that’s supe­rior to many others, simply because we have good fans.”

Jorma Lori, BioCan AG

Right away, Schefer thought of the AxiCool axial fans, which are normally used in cold stores but were a perfect fit for the require­ments. “They were much more compact than the fans I’d seen else­where, and easier to install,” says Schen­nach. That was impor­tant, because the two did every­thing them­selves. They installed a total of 20 units on the ceiling, and two Radi­Pacs each for intake and exhaust.

Schen­nach and Lori are very satis­fied with the results. “We have a facility that’s supe­rior to many others, simply because we have good fans,” says Lori. And the next ordered fans are already waiting to be put to work on the remaining floor space. Of the 3,000 square meters in Bassers­dorf, BioCan is only using about 1,000, and the demand for legal hemp – not only from private consumers but also from whole­salers – isn’t slowing down.

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