Cannabis legalization has been a passionate topic over the last few years and is engulfing many countries and states. In the beginning of the legalization movement, many Cannabis growers were only concerned with a few items such as plant nutrients, pH water balance or the type of halogen grow lights recommended. Very little, if any, thought was imparted to indoor air quality. Slowly, over the last 5 years, Cannabis growers are realizing that Indoor air quality provides as much value as any other technique in the growing process. Growers understand there are a large number of contaminants that can damage and wipe out an entire crop, thus learning about proper indoor air quality is quickly gaining prominence. Keith Jordan, Sanuvox Technologies, Inc. explains what air control systems are of use for cannabis facilities.
Cannabis growers operate in three methods – outdoor grow similar to a farm, greenhouse similar to vegetables, and fully enclosed warehouse with Heating, Ventilation, and Air Conditioning system (HVAC). Outdoor growers harvest once a year, greenhouse growers harvest roughly 4 times a year and warehouse growers harvest 6-8 times a year. The top of the line, best quality and quickest harvests occur with a warehouse grower. NAFA members can engage the role of educating the grower on the best and most efficient method of removing particulates, disinfecting molds, fungus, bacteria, and mitigating pungent cannabis odors.
The warehouse grower has anywhere from 100 to 10,000 plants inside a large room or multiple rooms which are full of dirt pots, 1000 watt growing lamps creating a massive heat load, circular fans on the walls stirring up dust, and high numbers of air changes per hour through the HVAC system. Operating indoors with the above opposing systems can rapidly increase the particulate load to that of dust storm. These opposing forces will continually increase the level of particulates as well as circulate those particulates around the room, through the HVAC system spreading contamination and dust virtually on every surface of the room. The current level of filtration for the majority of warehouse growers consists of a 1” MERV 8 pleated filter. Several reasons for this stem from utilizing 5 ton HVAC systems, choosing the cheapest filters, or a recommendation from an HVAC contractor.
The warehouse grower that has retrofitted a warehouse typically has multiple 5 ton AHU per room. The new facility built from the ground up typically has 15 to 25 ton AHU. Most growers are so concerned with overcoming the heat load of their grow lights and reducing humidification levels, that they are hesitant to increase filtration because of pressure drop. The HVAC contractor sizes the system to provide the grower with anywhere from 10 to 18 air changes per hour and does not educate the grower on the vast array of filtration efficiencies or sizes, thus why 1” MERV 8 pleats are the most common with Cannabis growers currently. This is a perfect situation where NAFA members can be of crucial benefit to growers in educating them that a higher efficiency filter will not necessarily affect the heating/cooling loads when sized properly and can lower life cycle costs of the filter as well as the AHU.