Disinfecting Air with UV-C vs. Filtering Air with HEPA Filters

With the ongoing pandemic continuing to affect the world we live in, more people are trying to improve the indoor air quality of their homes and businesses. HEPA filters and ultraviolet light are two common methods of air purifying. While both of them have the same goal of improving indoor air quality, the technology behind them is quite different and the type of air pollutants they can remove differ. No air purifier is perfect and without flaws. Both HEPA filters and UV-C light air purifiers come with their own set of benefits and disadvantages.

A HEPA filter is a “high-efficiency particulate air” filter made up of strands of randomly aligned synthetic fibers or glass. HEPA filters have been used by hospitals and in research environments for a long time. They are designed to trap particles that can come from pollen, pet allergens, viruses, mold and bacteria. The standard for HEPA filters is based on the (MPPS) most penetrating particle size of 0.3 microns. In order for a filter to be designated as a HEPA filter, it must meet international standards (ISO) to remove 99.95% of particles. In the United States, the standard is removal of 99.97% of particles. One important thing to remember about HEPA filters is that particles like viruses and bacteria are only trapped by the filter. If you do not replace them, then the air cleaning effectiveness goes down, and unclean filters can become a hotspot for dangerous pathogens. For this reason, it is recommended that proper PPE be used when replacing the filters. 

Traditional sanitation procedures typically do not include Air Handling Units or their accompanying ductwork. Formaldehyde used to be the most prevalent decontamination method used to attain a 6-log sporicidal kill of HEPA housings. This method was effective, but the process typically took over 12 hours and held considerable safety concerns, as formaldehyde is a carcinogen known to leave residues. When decontaminating with chlorine dioxide gas, it is often times very easy to include the ductwork and air handling system (even HEPA housings) in the scope of the project. CD gas penetrates through HEPA filters as if they are not there, and being a dry gas, it is able to navigate the bends of the ductwork system without condensing and getting "stuck."

Ultraviolet light air purifiers remove harmful pathogens from the air by actually destroying viruses and bacteria, not just capturing them. When a micro-organism is exposed to UV-C, the nuclei of the cells are altered due to photolytic processes. This process prevents further replication and causes cell death. The AirGlow is an in-duct ultraviolet light disinfection system that can be installed in any HVAC system. The AirGlow reduces and/or eliminates the growth of bacteria, mold and spores. It can also prevent the spread of airborne transmitted diseases including the flu and SARS-CoV-2 virus. As air passes by the quartz glass bulbs of the AirGlow, the travelling air is disinfected, and harmful organisms that may have been present are killed. To improve energy efficiency, the AirGlow can be positioned parallel to the cooling coils. When used on cooling coils, the Airglow is used to reduce biofilms that can accumulate on the coils. Clean coils can deliver a 30% increase in cooling capacity which in turn reduces energy consumption and costs.

HEPA filters clean the air with the use of filters located inside the air purifier. As polluted air passes through the device, HEPA filters capture many of these harmful pollutants and keep them trapped inside. HEPA housings should be decontaminated prior to filter changeout. Alternatively, ultraviolet light air purifiers use certain UV wavelengths to literally destroy airborne pathogens. Both of these devices ultimately share a common goal – clean indoor air – but one does not necessarily substitute the other.

Maintaining High Level Contamination Control with Passthrough Chambers

A clean room is only as clean as the items (and people) who enter it.  Autoclaves are utilized to sterilize some supplies and materials entering an aseptic area, but not all materials are compatible with a steam sterilization process.  Electronics and other materials that are incompatible with either high heat or moisture cannot be processed within an autoclave.  Those materials are typically wiped down with a liquid disinfectant, which ultimately offers a lower kill level and a potential for human error not wiping all surfaces properly.  The risk is greater for more complicated instruments where wiping hard-to-reach surfaces is impossible, such as the internals of a laptop computer.  Over the past 20 years, we’ve been working to identify and offer solutions to some of the gaps we find when working in barrier facilities.  Eliminating the risk of human error through the use of touchless pass-through chambers utilizing either chlorine dioxide gas or ultraviolet light is one such solution.

CD Gas Passthrough Chambers

As an EPA registered sterilant, chlorine dioxide gas can be used to ensure that items entering your facility are completely free of pathogens and unwanted organisms. Chlorine dioxide gas passthrough chambers can be utilized to decontaminate (or sterilize) items entering a barrier.  We’ve worked with Rack Washer manufacturers within the Life Science industry for over 15 years collaborating on Chlorine Dioxide Gas Decontamination Chambers as well as custom sized CD Gas Passthrough Chambers.  Both chambers are designed for the quick and easy decontamination of items within any governmental, pharmaceutical, laboratory, research or surgical setting. Passthrough chambers can be easily integrated into a new cleanroom design or installed into an existing cleanroom. It is used in conjunction with a chlorine dioxide gas generator to provide a rapid, fully automated, and highly effective method to sterilize computers, electronics, medical devices, sterile products, instruments, and components at ambient temperatures.  It also provides a cost-effective method to decontaminate components, parts, supplies, and equipment entering a “sterile” or “clean” facility at room temperatures and without the need for an expensive, space consuming, energy consuming sterilizer.  Passthrough chambers can also be used when removing items from a dirty or BSL level area to a clean area without the concern for cross contaminations.

The chlorine dioxide gas generator combined with a passthrough chamber features a sophisticated sterilant concentration monitoring system to ensure a tightly controlled sterilization process. All instrumentation, including the photometer for concentration monitoring, is easily calibrated to traceable standards. The process is easy to validate due to the repeatable cycle, tight process control, and highly accurate sterilant monitoring system.  A run record is produced that contains: date, cycle time, as well as relative humidity, temperature, pressure, and chlorine dioxide concentration. The equipment is available in a variety of sizes to meet your processing needs and can be manufactured with either a single door or double door pass-through orientation. A door interlock system is also available.

UV-C Passthrough Chamber

There are also UV-C passthrough chambers to disinfect small electronics, tools, components, and other liquid sensitive items entering a barrier facility or clean room. The Flash-Thru Chamber allows for the quick disinfection of items entering a sterile area using ultraviolet light. This chemical and liquid free system allows for the quick disinfection of tools and equipment quickly and efficiently treated upon reception and brought into the barrier. The Flash-Thru utilizes standard 110-240V electricity and supplies a UV-C dosage sufficient for achieving a 99% reduction of most viruses and bacteria within one minute. High-output UV-C bulbs last up to 16,000 hours. Their placement throughout the chamber interior, along with quartz glass shelving, ensures proper coverage of all items passing through to be fully disinfected.

Bringing equipment, tools, and supplies into a barrier facility is a potential pathway for pathogens to enter clean rooms. To learn more about pass-through chambers which can help eliminate dangerous organisms and preserve the sterility of your facility, visit our Products page and contact us to determine which option is best suited for your needs.

Decontamination of HEPA Housings

HEPA housings can undergo a decontamination process for multiple reasons.  Most frequently, HEPA housings are decontaminated prior to filter changeout. They can also be decontaminated as part of a yearly routine or during construction/renovation.  HEPA housings can be on the supply or exhaust side of an HVAC system for a facility. On the supply side, they are purifying the incoming air to maintain sterility for a clean facility. On the exhaust side, they are purifying the air exhausting a facility that works with biologically hazardous organisms to prevent their escape.  

Formaldehyde used to be the most prevalent decontamination method used to attain a 6-log sporicidal kill. This method was effective, but the process typically took over 12 hours and held considerable safety concerns. Formaldehyde is a carcinogen known to leave residues behind.  Both of these attributes are concerning, especially if a HEPA housing is on the supply side of the room.

Hydrogen peroxide vapor is another decontamination method utilized for HEPA housing decontamination.  Due to adsorption issues into the HEPA filter itself, aerating HEPA housings can take considerably longer and typically lasts overnight.  Adsorption into the filter material can cause uneven concentration amounts on either side of the filter too, potentially limiting the success of the decontamination.

Chlorine dioxide has become a more optimal decontamination method, especially when considering HEPA housings.  Chlorine dioxide gas works faster, with overall cycle times between 1.5-3 hours.  Part of this is because chlorine dioxide does not leave a residue and the aeration time is shorter.  For exhaust HEPA housings, aeration is accomplished by simply turning on the exhaust blower and opening the “infeed” and “exhaust” dampers on a HEPA housing. This method aerates a HEPA housing in under a minute. For supply HEPA housings, this is accomplished by using a carbon scrubber to break down the CD gas. This method aerates a HEPA housing in under an hour.

To read more about decontaminating HEPA housings, please click here.

The Importance of Clean Breaks in Production

Scheduled production downtime is often perceived as a loss of profit. In actuality, fewer machine breakdowns mean a more efficient operation, and scheduled downtime for sanitation provides a “clean break.” By definition, a clean break is a production break that involves a documented, verified, and validated cleaning and sanitation process to ensure sterility upon completion. In practice, a clean break is a damage limiting event that defines the maximum quantity that could be recalled in case of a contamination. It assures microbial contamination cannot overlap from one production run to another. Financially, a clean break is like an insurance policy, money spent on something you hope gives you no return on investment. Emotionally, a clean break is peace-of-mind.

Clean breaks are an important component of an effective traceability program. If a recall were to occur, it will include all product that was packed from the last full cleaning and sanitizing event forward. The product that is processed between clean breaks is called a lot. The more frequently clean breaks are established, the smaller the lot. If a facility’s clean break cannot be defended during a recall, then as far as an investigator is concerned, that company did not have one. When that happens, the recall will only grow. In October 2018, McCain Foods recalled 63 different products back to a shipped date of January 1, 2016 because they did not have a more recent clean break.

If contamination is detected, the question of how far back to recall can be painstaking, especially if the decontamination process utilized is not 100% effective. Typical cleaning and sanitization methods can have difficulty guaranteeing that all organisms have been contacted or contacted with the proper effective dosage. Therefore, these techniques may not eliminate all of the organisms, leaving some to reproduce. Modern fumigation methods, such as use of gaseous chlorine dioxide, can completely eliminate all of the organisms and thereby “reset” a facility. Chlorine dioxide gas is able to achieve a complete 6-log sporicidal decontamination of all surfaces within a space, including hard-to-reach areas such as cracks and crevices, because it is a true gas above -40 degrees and its molecule size is smaller than the smallest virus. Once the gas has been removed, the area is safe and does not require additional cleanup. 

Similar to a firebreak in a forest, a clean break provides companies with that line of safety. The strategic use of preventive scheduled downtime leads to a safer, more reliable, more efficient operation. By using chlorine dioxide gas routinely for decontaminating a facility before an issue arises, the chance of a contamination and/or a recall declines drastically, potentially saving money, disruptions to business, and perhaps lives. ClorDiSys’ decontamination method and approach to process control has enabled us to be trusted to keep critical environments safe, including most major pharmaceutical companies and 31 of the Top 100 food manufacturers. If you would like to learn more about clean breaks, how to establish the scope of a project, or our decontamination services in general, please contact us at sales@clordisys.com or complete this form.

From Seed to Storage: Sources of Contamination in Cannabis

Unless cannabis is grown in a clean room with appropriate air filtration and other good laboratory practices, it is inevitable that contaminants will be found on cannabis flowers and products made with them. Many cultivators are discovering that contamination is a huge risk no matter how careful they are. The most common types of contamination are microbial but also include pesticides, heavy metals, and residual solvents. Contamination can happen during the cultivation, harvesting, drying and curing, or extraction processes. Cannabis plants and products can pick up molds or bacteria while growing (particularly if grown outdoors or in an unsanitary indoor environment) or during subsequent handling and processing. Cannabis is often exposed to contaminants when held in long-term storage. There are multiple ways cannabis can become contaminated from employees to supplies to environmental factors that are outside of your control. The best way to avoid an issue is by being aware of how cannabis can be contaminated in the first place.

1. EMPLOYEES Handling cannabis improperly is one of the most common ways to contaminate it. Handwashing is the most basic and effective strategy to prevent cross contamination at your farm or facility. Employees should wear clean scrubs and face masks when handing the flower, especially during post-harvest processing. Gloves should also be worn and changed every time they come into contact with something other than the plant. Ensure your staff stays informed and follows best practices is ultimately the best line of defense.
   
   
2. EQUIPMENT AND SUPPLIES There are a lot of tools that are used to grow and process cannabis, such as buckets, scales, and scissors. Make sure that there are supplies for each room and that these supplies aren’t being transferred from one area to another, which can increase the possibility of cross-contamination. Unsanitized equipment and supplies can easily cause contaminants in the form of mold, bacteria and even heavy metals from old equipment. If your machinery is contaminated with spores, you can easily cross contaminate your crop during any phase of the harvest process. This can either destroy your crop or become a major health threat if your final product is compromised. Establish equipment, surfaces and storage cleaning protocols using effective methods to eliminate pathogens.
   
   
3. HARVEST AND POST-HARVEST A large percentage of mold begins after harvest as a result of poor air quality and high moisture levels. This situation becomes a prime time for the plant to become contaminated with mold. Mold can grow on almost any substance where moisture is present, and it reproduces by spores that can easily travel through the air with the right gust of wind and attach to your skin or plants. Extra care must be taken to ensure that–during drying and curing–temperature, humidity, and air circulation are being controlled. Later after the drying phase, you will also want to confirm that your final product is safe by testing for mold, mildew and other microbial pathogens.
   
   
4. ENVIRONMENTAL A lot of cultivation facilities are in areas that do not have the best environments for growing cannabis. Between indoor and outdoor, each type of grow has its pros and cons. Indoor cannabis growers can potentially control the room's temperature, humidity, light intensity, and CO2 levels to achieve idyllic growth rates and conditions. The right combination of moisture, temperature, humidity, and light can help accelerate the growth of both cannabis and its pests. If contaminants or toxins enter one of your grow rooms, it may be difficult to detect and eliminate. Because fungal spores are extremely small, they can eventually get into a facility through the HVAC system. If growing indoors, you must completely sanitize your space to kill all microbes before you start. While this will prevent most issues, unfortunately traditional cleaning methods may not prevent all airborne spores that exist in small cracks, for example. You must also make sure there is always proper ventilation.
   
   Growing cannabis outdoors is the most natural and least expensive way. Plants grown outdoors with natural sunlight will grow to their full genetic potential and will have a full and natural terpene profile. Much less energy is required (no lights, no cooling/heating) and nutrients can be regenerated and recycled. However, plants grown outdoors are exposed to all of the elements, all the time. This includes the environment, weather, pests and animals, which can have a very big effect on the final product. For growing outdoors, it is common for cannabis producers to use pesticides and insecticides on their plants. Unfortunately, these pesticides can go on to create issues themselves if they are not thoroughly removed from the plant matter during processing as many fungicides and insecticides can be harmful to human health. Although pesticides are one way to control contamination, they’re not a perfect solution, and every state treats them differently.

As the legalization and medicinal utilization of cannabis increases around the world, so does the potential threat of contaminants making their way to consumers. Policing the quality and safety of cannabis products is far from straightforward. At the federal level in the United States, cannabis is still considered an illegal drug, so states have to determine on their own how to protect millions of cannabis users. The result is an uncertain and occasionally incoherent regulatory landscape with no consensus. Cannabis cultivators are familiar with the challenges faced as contaminants pose a potential threat to their consumers. By learning about the sources of contamination as well as prevention and remediation options, growers can more confidently face testing and consistently provide a safe product.

For further reading on this topic and references, read the Common Sources of Contamination in Cannabis Application Note. Visit the Cannabis Applications page to learn more about the benefits of utilizing chlorine dioxide gas and ultraviolet light for microbial decontamination and mold remediation.