The concept of cannabis consumption lounges is relatively new. One of the largest challenges facing consumption lounges is proper ventilation. While not all consumption lounges are strictly available for cannabis consumers to smoke in, most allow consumption via smoke and vape devices. This can create issues for those looking to enjoy cannabis through edibles or topicals. Proper consumption lounge ventilation is vital to creating a space that allows all cannabis consumption types to have an enjoyable and smoke-free experience.

Addressing State Regulations

Many states are adopting regulations that address indoor air quality within smoking portions of consumption lounges. Some of these include the following:

Smoking areas must be maintained negative to other spaces.
Removal of visible smoke existing in the building.
Elimination of Odor from exiting the building.
Require use of HEPA filters.
Minimum required air changes per hour (15-30ACH).

Many local jurisdictions are coming up with their own regulations instead of following already established methods of handling smoking in buildings. The American Society of Heating, Refrigerating, Air Conditioning Engineers (ASHRAE) has an established standard 62.1 - 2022 “Ventilation and Acceptable Indoor Air Quality” written by objective industry experts on how to provide for ventilation in buildings. This standard also addresses best practices for handling smoking spaces in buildings. This is more than adequate to give Engineers guidance on how to protect the health and welfare of the public in these spaces.

There are many ways to address the above parameters, the key will be utilizing the most efficient and maintenance friendly means to protect the public while keeping the cost as low as possible.

Maintaining Negative Spaces

Areas of the space that allow for smoking or vaping must have more exhaust than their surrounding spaces. Airflow must be in the direction from nonsmoking to smoking spaces. Refer to the following diagram:

Both HEPA and MERV13 filters will reduce if not eliminate visible smoke. However, both have implications that need to be taken into consideration.

MERV 13 Filter: A MERV 13 filter can remove at least 50% of particles that are 0.3–1.0 microns in size, at least 85% of particles that are 1.0–3.0 microns in size, and at least 90% of particles that are 3.0–10.0 microns in size. Smoke particle size is in the range of .01 - 2.5 microns. Since the human eye can only see individual particles that are around 40-50 microns, removing visible smoke particles should prove simple and efficient with a MERV 13 filter.

Removal of Visible Cannabis Smoke

MERV 13 Filter: A MERV 13 filter can remove at least 50% of particles that are 0.3–1.0 microns in size, at least 85% of particles that are 1.0–3.0 microns in size, and at least 90% of particles that are 3.0–10.0 microns in size. Smoke particle size is in the range of .01 - 2.5 microns. Since the human eye can only see individual particles that are around 40-50 microns, removing visible smoke particles should prove simple and efficient with a MERV 13 filter.

HEPA Filtration: Some local jurisdictions require HEPA filtration for consumption lounge ventilation, which removes particles 0.3 micron and larger in size. It is also 99.97% efficient and much more expensive than a MERV13 filter ($500/ea. Vs $20/ea.). HEPA filters move less air through them causing there to be more of them and have higher pressure drop, which will require larger fans and motors to move the same amount of air than a Merv13 filter. This will also increase the energy used to perform the filtration. HEPA filters will also get loaded up faster, requiring them to be replaced more often at 20 times the cost of a MERV13 filter.

Both HEPA and MERV13 filters are effective at removing visible smoke. However, the system will need 125% more HEPAs filters which will need to be replaced more often and cause more energy use as compared to MERV13.

SMOKE REMOVAL DEVICES

There are other ways to remove visible smoke besides filtration. The following is a list:

Electronic Smoke Removers: These use electrical charges, such as negative ionization, to remove odors, and some may produce ozone as a byproduct. Which has been shown to be unsafe for occupants at certain levels.

Electrostatic Systems: These use positively and negatively charged metal plates to collect smoke particles.

Ozone Generators: These pump out volumes of ozone to neutralize odors, but as mentioned previously, ozone at these levels could be dangerous to breathe.

Smokeeter Systems: These systems use a motor/blower assembly to draw air through an aluminum mesh filter, then use an ionizer to give particles a positive charge, which are then collected on cell plates.

Odor Control

Cannabis odor is a compilation of terpenes that are released. Terpenes exist naturally, they are the smell associated with roses, hops and other flowering plants. More than 200 distinct terpenes have been identified in different strains of cannabis. The actual smell depends on the quality and combination of the terpenes found in the flower or concentrate. There are many different methods to reduce and or eliminate cannabis odor.

Carbon Filters: Cannabis gases (AKA terpenes) are very small molecules that easily pass through standard filter media. One cost effective means to address cannabis odor in your cannabis lounge ventilation system is to use activated carbon filters to remove odor. Carbon filters absorb impurities also referred to as VOCs (volatile organic compounds). Carbon in these filters are porous. As the gas molecules (odor) move through the carbon filter, the odor molecules stick to the carbon surface. The more porous the carbon the better it will work. At some point the carbon will absorb its maximum capacity of carbon and will need to be replaced or re-generated.

Depending on the carbon filters manufacturer, it may be possible to regenerate carbon for reuse by washing and heating it in an oven. Under controlled temperature and time, the carbon can be regenerated for reuse.

Electrical Charge Filters: There are other methods to remove odor besides carbon filters. The use of sophisticated electrical charged filters as well as, masking the smell with other smells has proven useful in reducing and eliminating cannabis odor. Some are more effective than others and have a cost and maintenance associated with them.

Recommended Air Delivery System for Consumption Lounge Ventilation

There are many HVAC systems to choose from. However, there are several criteria including but not limited to application, cost, maintenance, serviceability and energy use that should be taken into consideration. The HVAC system that Anvil Agrinomics recommends for cannabis consumption lounges that allow smoking is a constant air volume displacement ventilation (DV) system that utilizes natural convection heat transfer to condition the space. This coupled with advanced, maintenance friendly air cleaners and 100% outdoor air units, utilizing energy recovery should provide a much-improved indoor air quality and thermal comfort for the consumption lounges, especially those that allow smoking.

What is Displacement Ventilation?

To understand displacement ventilation (DV) it is first easier to describe a typical overhead mixing system because of its familiarity in the industry.

Overhead Mixing System

An overhead mixing system pushes large amounts of conditioned air into the existing occupied air space that is being heated by people, electronics, lights, exterior walls, etc. The job of a mixing system is to dilute the heat in the space with enough cooler air to maintain the desired space temperature. The space air also contains contaminants – volatile organic compounds (VOCs) from carpet, paint, adhesives, CO2, dust, dirt, pollen and, in the case of cannabis consumption lounges, smoke. The result of diluting the heat with 55°F is a resulting mixture of air that is the desired space temperature (74°F). The diagram below illustrates an overhead mixing system.

Figure 1. Typical Overhead Mixing System

Displacement Ventilation

Displacement ventilation relies on natural principles of air movement to condition the space (convection heat transfer). It is common knowledge that heat rises. The heat produced by people, computers, lights, and smoking etc. will rise in a plume if left undisturbed and not mixed into the space. DV delivers the air low in the occupied zone (where people reside) at a very low velocity (50 ft/min) and slightly warmer air temperature (60°F to 65°F). This air flows towards objects generating heat to replace the air that leaves in the heat plume. As heat rises off its source, due to buoyancy forces, the conditioned air is pulled up and around the object to replace the air in the heat plume. As the heat rises, it also carries with it air-borne contaminants such as VOCs, CO2 and smoke.

As the heat and contaminants rise, the cleaner, conditioned air is left in the occupied zone and the warmer, contaminated air is pushed to the unoccupied zone. This helps separate the contaminants (including smoke) from the air in the breathing zone. We can then treat the contaminated air or exhaust it from the space. Refer to the diagram below.

Figure 2. Displacement Ventilation Air Distribution

Considerations for Consumption Lounge Ventilation: Ceiling Height

It should be noted that spaces with lower ceilings will need to be evaluated to determine if displacement is a good fit. For instance, depending on the density of the load and a ceiling lower than 9 feet may require more supply and return air than typically used in a displacement system. Which is not a problem, it just needs to be evaluated and then appropriate solutions developed to handle the situation.

Displacement Ventilation Opportunities and Challenges

The following is a list of general opportunities and challenges for the displacement ventilation system that could likely be applied to cannabis consumption lounge ventilation (brief explanations for each of these items are included within this report):

Opportunities

Potential 20% reduction in cooling capacity
15% to 20% reduction in HVAC energy consumption
Indoor air quality improvement of 33% over traditional mixing systems
Better control of humidity, temperature and space contaminants

Challenges

Possible contractor unfamiliarity with system
Test and balancing for system unfamiliarity of contractors
The emphasis on integration of diffusers with architectural features
Emphasis on the unique selection of equipment
Increased commissioning requirements
Direct digital control sequence uniqueness

Although we have listed both opportunities and challenges, we believe that with the appropriate coordination between the Architectural and the MEP Engineer; and if appropriately addressed in the construction documents, pre-bid meetings etc. the negative aspects of the system can be overcome and the building owner will have a system that adds benefit and value.

Energy Savings Analysis

It is difficult to determine exactly how much energy can be saved using DV without a complete energy analysis for each project and location. However, we have seen energy savings between 15% and 20% over a typical air mixing system. Energy model simulations have also generated similar energy saving results.

Diffuser Location Coordination

The location of diffusers will require coordination since one of the principles of displacement is to deliver the air low in the occupied zone. The engineer must work with the architect to integrate the diffusers into architectural features so as not to negatively affect the aesthetics of the space. The manufacturer of these diffusers has flexibility in the size and shape that should help us in accomplishing a seamless integration. Our goal will be to integrate the diffusers to minimize their presence in the space while delivering air where appropriate.

Varying Construction Costs

DV systems have different costs as compared to a mixing system. There are trade-offs that we have found that show the DV systems lower in first cost, at best, and slightly higher, at worst, when compared to a traditional overhead mixing system.

There is an opportunity to reduce the overall tonnage of the HVAC system and the possible reduction in ductwork due to simpler duct routing and reduced number of diffuser locations. We can’t ignore the cost of humidity control and 100% outdoor air delivery plant because this would be necessary for both systems depending on location. There is an additional cost associated with controls as well as the cost of the diffusers themselves. These items should be offset by other reductions.

We have utilized displacement ventilation to solve a number of indoor air quality problems in the past. Anvil Agrinomics believes that this system will provide the best possible IAQ for cannabis consumption lounges that allow smoking, while minimizing the energy needed to do so. By delivering the outdoor air directly to the occupied zone at a low velocity and minimizing mixing, the heat and smoke will be pushed out of the occupied zone where it can more easily be removed from the space. This once-through air flow/ exchange principle can be used in conjunction with other air cleaning strategies as budget allows, to create a consumption lounge ventilation system that provides a much improved environment for patrons and employees.

Summary

The combination of filtration and odor control along with smart efficient air delivery systems will be very effective at meeting local jurisdiction requirements for consumption lounges. As new states allow for cannabis consumption lounges, we highly recommend encouraging legislatures to adopt applicable standards from professional organizations that remain objective and are created from experts in their respective industries.

Why Partner With Anvil Agrinomics?

Anvil Agrinomics, LLC (AnvilAg) is a leading MEP (Mechanical, Electrical, and Plumbing) engineering design firm centrally located in the United States. While we serve a diverse range of industries, our specialty lies in designing controlled environments for indoor agriculture and facilities dedicated to the manufacturing of infused products. Our expertise helps businesses optimize their operations and achieve regulatory compliance while creating efficient and sustainable environments.

Ventilation in Cannabis Consumption Lounges