Pressurized Indoor Grow Rooms
Harmful contaminants such as bacteria, viruses, fungi, yeasts, molds, pollen, gases, VOC (volatile organic compounds) could wreak havoc in an indoor grow operation if they spread from one room to another. Airflow inside grows rooms should be designed to either keep these harmful pathogens out during regular operation or, unfortunately, if an infection does happen. They should contain them within the room until the cleaning crews can get to it. Positively pressurized rooms are used to keep the contaminants out, whereas Negatively pressurized rooms help to keep the contaminants from spreading out of the room. By controlling the amount of inlet supply air over the outlet exhaust air from a room, the room can switch from positive to negative pressurized depending on the operating condition. Typically a pressure differential between the inlet and outlet of no less than 2.5 Pascal (Pa), or ideally 8 Pa differential, is needed to maintain a positive or negatively pressurized room as per ASHRAE/ASHE Standard 170–2017.
A smoke test is a traditional way to verify if a room is under positive or negative pressure. However, this can get messy, interfering with the daily operation, or worse, the chemicals used to generate the smoke can be detrimental to plants. Edyza, with its high-density wireless sensor network, can monitor continuously changing barometric pressure in a grow room. Additionally, our wireless sensor network can detect leaks inside the rooms using their high precision barometric pressure sensor, which is better than 1.6 Pa.
Above is a plot of barometric pressure values in hectopascals (hPa) from 63 wireless sensors inside an indoor grow room. The blue region on the plot represents a low-pressure zone through which air is leaking out while the red zone represents air inlet. The above room has an internal pressure differential of 4.0 Pa, which puts within ASHRAE specification for a pressurized room for contamination isolation.
Our wireless sensors collect a barometric pressure sample every 30 seconds from a sensor. This results in over 8400 pressure values per hour from a room, which is then used to mathematically model air mixing within this closed space. Our air mixing visualization can identify in real-time, stagnant locations inside a grow room that may cause humidity pooling or identify a location on the boundary walls through which pressure leakage and possible contamination can spread between rooms.
All of the above data granularity is possible because of our high-density wireless sensor network. Instead of just having a single sensor capture a room's data point, we typically deploy more than 60 to 70 units per 2000 sq.ft grow rooms. The image below is an example of an Edyza wireless sensor deployment. The image was captured before the plants are moved into this room. Our wireless sensors are deployed on a vertical rod in this grow room that is placed approximately 6 ft apart. There are 48 sensors on the benches and 15 sensors on the surrounding walls.
