As fire professionals, it is important to understand the hazards associated with new and rapidly developing trends in building use and construction. The cannabis industry has rapidly increased in the United States with little change to building and life safety codes. On a political level, some states and national organizations have hesitated to develop code regulations for cannabis which are in direct conflict with the legality of cannabis, federally. This has created a void for enforcement officials, design professionals, and the cannabis industry to develop their own guidelines and measures for building and life safety.
I don’t know what I had expected, but it certainly wasn’t what I saw during my first visit to a cannabis cultivation facility. I looked over to my colleague, dressed in a hairnet, a white, disposable coverall, and blue shoe covers. We stood in an air chamber and let the nozzles blow any residual pollen off our clothes. As we stepped out of the chamber, I saw a grower walk by in a white lab coat. We passed a wheeled cart carrying computers and a number of measurement devices used to determine moisture content and nutrient levels in the soil. The air had a noticeable acrid smell, not as pungent as a skunk, but stronger than fresh hops. We walked into a flower room first. The red and blue LED lights made the plants appear purple. The room was filled with cannabis plants, standing 1.2m tall, densely packed together on sliding tables. Our guide, the owner of this facility, explained that with the increased density, the plants grew taller. This forced the trichomes (the sticky substance on the surface of the plant where the cannabinoids are found) to be more concentrated. He pulled out a loupe from his pocket and we took turns looking at the magnified leaves to see the trichomes. As he continued his explanation, my original preconceptions of cannabis cultivation were changed. I had expected a casual growing operation, or perhaps an indoor farm setting. This facility was best described as a laboratory. Every aspect of the growing operation was meticulously measured, evaluated and analyzed. This was truly “technical growing”. This was my first visit to a cannabis cultivation facility, but certainly not my last.
Cannabis has been used for medicinal and recreational purposes since 800 BC. The development of a cannabis plant is suspected to have originated in Central Asia. The hemp products and plant materials were used as strong fibers and the seeds and leaves were ingested during religious ceremonies. As the influence of cannabis spread across the world, the medicinal purposes of the plant were explored and applied as an anesthetic to mitigate pain. Evidence of cannabis application can be found in Indian, Middle Eastern, and European culture. Cannabis reached the height of its popularity in the late 19th century. The continued advancements in medicine and research into cannabis resulted in its appearance in common cures for headaches, minor pains, topical creams, and as a sleeping remedy. As countries developed strict narcotics regulations in the 1900s, medicinal cannabis usage was considered illegal and greatly reduced or eliminated. Cannabis has recently experienced a resurgence as the ban on specific narcotic elements has been reduced. As current technology is applied to cannabis research, more applications for cannabis have been discovered. It is expected that at the minimum, the medicinal application of cannabis will increase in the United States and worldwide.
As cannabis cultivation and use is decriminalized in more areas across the United States, it is important to provide a national standard for cannabis cultivation. This standard will ultimately set a life safety precedent through code regulations.
The National Fire Protection Association (NFPA) has gathered a technical committee and developed a standard for building and life safety through the newly introduced Chapter 38: Marijuana Growing, Processing, or Extraction Facilities in the 2018 edition of NFPA 1: Fire Code. However, to understand the implications of these newly developed regulations, it is first important to understand the growing cycle of cannabis and some context of cannabis processing.
Cannabis begins its life in the form of a seed. The seed sprouts into a seedling (in the 1-2 week germination phase) and is placed in a controlled setting and grow medium. The seedlings are typically subjected to alternating 12-hour to 16-hour cycles between white light and complete darkness. The wavelength of the white light aids in the cannabis plant’s initial development. Moisture and humidity control are crucial for providing the seedling with the proper atmosphere for growth. The seedling stage lasts for 2-3 weeks.
The vegetative stage lasts from 2 to 8 weeks as the seedlings develop into mature plants. The plants are subjected to high moisture and humidity levels to mirror an ideal tropical environment. Light cycles of 12 to 16 hours of white light are used to further increase photosynthesis and develop a controlled, uniform, growing environment.
The flowering stage follows the vegetative stage. The mature plants flower, creating buds. The concentration of the chemical cannabis element is highest at the buds and the immediately surrounding leaves. The flowering stage can last from 6 to 8 weeks and requires approximately 12-hour light cycles. Some growers may use light of different wavelengths to promote different proteins to emerge from the cannabis and enhance the end product.
The final stage of the growing process is the harvest. Harvest can either be cyclical or complete. Some growers will harvest the mature buds and leave the younger buds on the plant for development. In most medical marijuana cultivation facilities, the entire grow room is harvested to allow for cleaning and sanitation of the room in preparation of the next batch of plants. The harvested plants are trimmed, the buds collected, and the remaining leaves are gathered for processing.
The most recognizable hazard associated with cannabis cultivation facilities is not growing, but rather processing. The cannabinoids, the oil containing the active elements, is contained within the trichomes. Trichomes are miniscule growths which comprise the sticky substance on the surface of the leaves and buds. The buds can be sold as an end product without processing but the trichomes on the leaves and trimmings needs to be extracted. One of the most common methods of extraction is by using butane or propane (LPG).
There are many techniques available to process cannabis into an end product. Carbon dioxide can be used to produce an oil. Alcohol can be mixed with the leaves and evaporated, leaving a concentrated solution which can then be processed further into baked goods or cooking oils. The buds can be trimmed into various grades, ranging from a whole bud to a powdery substance. Most cultivation facilities incorporate a variety of processing techniques to provide a range of products for the consumer. LPG extraction is one of the most popular forms of processing, and also the most hazardous form commonly used.
Processes utilizing flammable gas are regulated in some form through the application of NFPA 58, Liquid Petroleum Gas Code, but the unique application of LPG for cannabis extraction is not specifically covered. The plant material comprising typically of trimmings, leaves, and substandard stock are packed into a cylinder. LPG, either butane, propane or a combination of the two, is piped from a tank, to the top of the cylinder. It is allowed to flow through the plant material. The trichomes dissolve in the LPG and exit the cylinder through a fine mesh, leaving the plant mash behind. The resulting substance drips into a secondary container. The LPG is mostly recaptured through the closed system by utilizing slight temperature changes. The change in temperature, in turn, alters the pressures within the closed system and forces the LPG to be collected in the desired container. Since LPG is a gas in standard temperature and pressure, it evaporates from both the end product and the mash, given sufficient time. When the process is completed, the end product is removed and the plant material is discarded. The most hazardous part of the process is when the containers are opened and a small amount of LPG vapor escapes into the atmosphere. There is a history of flash fires and explosions associated with LPG extraction due to the release of LPG vapor.
NFPA 1 Chapter 38, Marijuana Growing, Processing, or Extraction Facilities, has captured the majority of obvious fire service concerns regarding commercial LPG processing of cannabis. If adopted by a jurisdiction, the LPG processing space will be required to be located within a dedicated room. The extraction room must have classified electrical equipment, a ventilation system interlocked with the electrical equipment (including the extraction apparatus), and continuous gas detection. Additional requirements for an automatic fire suppression system, restrictions on storage of LPG tanks (not in use) and NFPA 704 hazard rating signage on the door provide additional measures of building and life safety.
The 2018 NFPA 1, Fire Code is currently published and can be used as a guideline for authorities having jurisdiction when assessing a cannabis cultivation facility planned in their area. As the cannabis industry continues to grow and new methods for processing are developed, we can expect the national standards to follow suit to continue to provide a guideline for building and life safety.
For more information, go to www.nfpa.org/1