Part Six of the Guide to Marijuana Facilities Design
A design professional providing services in the construction of a grow facility must be aware of a wide variety of risks not necessarily seen in typical construction. These include the following:
Threat of Explosion and Fire
Marijuana facilities face a significant risk of fire or explosion. In 2014, there were 32 reported butane hash-oil explosions in Colorado alone caused by using unapproved butane open-blast extraction. Breweries, too, face a surprising risk of explosion from grain dust.
Municipalities have imposed requirements on marijuana extraction facilities and grow facilities and breweries to reduce the risk of explosion. The special design required in butane-based extraction is illustrative of the concern municipalities have regarding the unavailability of manufactured equipment that will safely perform the desired process.
At marijuana grow facilities, workers are also subject to chemical exposure from fertilizers and pesticides, from sulfur dioxide as a result of fumigation, and from carbon dioxide asphyxiation.
Damage to Real Property
Because the business is illegal under Federal law but legal by state law, there is a concern that the federal government will intervene and prosecute owners of grow rooms. For this reason, the facilities that house these grow rooms are frequently leased in most cases. As leased spaces, they are not designed to be used for this purpose. The environment required for a grow room can wreak havoc on a structure built for other enterprises.
The conditions of these grow rooms are nearly identical to those of an indoor pool. Temperatures between 75º and 85°F and relative humidity [RH] values range between 60% and 65%. This elevated level of humidity comes from the natural transpiration of the plants themselves. The high levels of relative humidity can lead to condensation on building components. Many ‘big box’ buildings have not been designed to handle the resulting temperature gradient, moisture migration via air movement, and vapor diffusion from interior to exterior space. Elevated temperatures, together with the higher RH, are even more detrimental in cold climates where winter temperatures are cooler for longer periods of time. This causes the vapor drive to be directed from inside to outside, where it can be trapped within the wall/roof, or the wall/roof components can be exposed to this condition for a longer period of time before it can naturally dry out.[ii]
Elevated temperature and RH can also produce an ideal environment for the propagation of biological growth and an increased likelihood of building material deterioration. This can range from moldy drywall and insulation to deteriorated structural components. This can not only cause health issues from poor indoor air quality, and can make the structure susceptible to further damage from the elements.
Finally, with increased moisture also comes an accelerated rate of building material deterioration, including gypsum roofs, wood walls, and insulation.
Computerized control systems monitor the environment and operate the equipment to maintain optimum conditions to maximize the crop yield. Failure of the computer system or electoral system can result in compromise of the plants.
Means of Egress as required in IBC, Chapter 10 is an important consideration for the facility. Marijuana growers typically do not grow in a building with one large open room. They need to isolate the plants that are at different stages of growth. Large converted warehouses can be maze-like with multiple rooms. Care must be taken to ensure that egress paths are clear and do not become blocked by equipment or storage containers.
[ii] Smoot, Humidity ‘gets high’ on Medicinal Marijuana, Interface, October 2012..