Part Five of the Guide to Marijuana Facilities Design
Manufacture of Infused Product
After marijuana is harvested, it is processed for sale in another facility. While the sale of marijuana flowers still makes up a majority of the type of product sold, the sale of concentrates is gaining a larger percentage of the total sales every year. These products take many forms, from oils, to vapes, from shatter to edibles.
Concentrates are exactly what the name implies — a more concentrated form of tetrahydrocannabinol (THC), the principal psychoactive component of the marijuana plant. THC can be extracted in a highly-concentrated oil. Extraction using butane is the most cost effective, yet the most dangerous method used. For this reason, many Fire Codes prohibit open releases of butane to the atmosphere during the extraction.
Several manufacturers produce equipment that cycles butane around a closed loop system passing through the plant material. The butane under pressure in liquid form acts as a solvent and breaks the THC from the plant. The butane is then recollected, and oil can then be retrieved. Currently there is no listings [such as UL] for this equipment. Thus, Denver and other jurisdictions require an engineering analysis of the extraction process, signed and stamped by a professional engineer.
Businesses using this equipment are also required to have a hazardous exhaust system installed to capture any potential release of butane, and the Colorado state marijuana laws require that the operation be in a dedicated room. Additionally, a local hydrocarbon detector is required to alert the operator of butane leaks.
CO2 extraction is another method of producing marijuana oil. The equipment must follow the same approval and permitting process as the butane equipment. Although there is no explosion risk as there is with butane, the systems can run at pressures as high as 10,000 pounds per square inch (psi); consequently, the equipment must be reviewed to ensure it is constructed appropriately. Businesses using this equipment are required to perform the extraction in a dedicated room, and a local CO2 alarm is required to alert of CO2 leaks.
Another extraction method is an alcohol distillation or heated evaporation process. Although alcohol is common, any flammable liquid can be used. Marijuana is soaked in alcohol and then the liquid is boiled off, leaving the oil behind. Larger operations recapture the alcohol in a distillation process for reuse. This process can also be used as a refinement after a CO2 or butane extraction. A number of methods and types of equipment can be used for this extraction process. When employing this process, a hazardous exhaust hood is required over the extraction process to capture any flammable vapors released, and equipment must be rated for heating flammable liquids. The one exception is a piece of equipment called a “solvent distillation unit” that is regulated in International Fire Code 3405 and has a UL listing specifically for distilling solvents.
Process facilities also frequently contain other operations within the same facility which test and certify the safety and potency of the marijuana product.