Design germicidal products for healthcare, air filtration

Article By : Jeff Davis, Intertek

Light source, safety, and ozone emissions are major factors that engineers designing germicidal products must consider.

Germicidal electrical equipment typically incorporates light to inactivate germs and viruses. It’s accomplished by producing light output in a range that may render microbes non-infectious at a molecular level. They are used in healthcare facilities and air filtration systems, and the technology is now being increasingly integrated into products used in homes, schools, offices, and other public spaces.

Germicidal products are not necessarily lighting products. Sometimes they are straightforward lighting products, an ultraviolet (UV) lamp, for example. Other times, they serve another purpose and integrate light output to target bacteria and viruses. Appliances like dishwashers have integrated the technology to kill bacteria.

Some products’ sole purpose is sanitizing places and devices like cell phones, keyboards, and clothing, using light to accomplish this goal. As such, these products are quite complex, often serving multiple purposes and having several considerations for their design and manufacture. Keeping some of these in mind may help ensure a successful product launch.

Light source selection

Germicidal products typically rely on UV light sources such as mercury lamps, light-emitting diodes (LEDs), excimer, and high-intensity discharge (HID) technology. The lighting source is defined as a specific nanometer region to inactivate harmful organisms like germs and bacteria.

photo of a row of UVC germicidal lamps

When selecting a lighting source, it is important to consider the product’s end-user, environment, size, and design specifications. When it comes to lighting, manufacturers should consider the type of radiation emitted; for example, if the product uses the UV light or it’s UVA, UVB, or UVC light. Moreover, it’s important to consider whether the radiation presents a health hazard that either needs to be mitigated or addressed through labeling, marking, and instructions.

Another crucial factor is light distribution. It’s important to ensure that the proper area receives the light, the light is of correct intensity, and that it’s not focused elsewhere in a way that might harm people. These concerns can be addressed during product design to ensure optimal use of the light. They can be evaluated to acceptable industry standards for safety, performance, and manufacturers’ specifications and design goals.

How to ensure safety

All electrical products need to be designed and produced with safety in mind. Ensuring the safety of electrical products is important to meet regulatory requirements and standards. It also helps build a reputation and ensure customer satisfaction and product success. As with any electrical or lighting product, germicidal products require testing and certification to ensure they comply with industry standards, can be legally sold and utilized, and are safe for use in the public domain.

Germicidal products need to be designed and tested to ensure that there are no risks of electric shock, fire, mechanical hazards, and optical radiation. Other considerations include compliance with electromagnetic interference (EMI) requirements.

Given the complexities of these products, there are several organizations overseeing safety guidance, and it is important to know and understand the requirements that each one of them has in place, as some of them will focus on workplace or user safety. In contrast, others will refer to healthcare considerations. These include health organizations like the U.S. Food and Drug Administration (FDA), Centers for Disease Control (CDC), and Health Canada. The Occupational Safety and Health Administration (OSHA) in the United States also has safety requirements, and the Federal Communications Commission (FCC) has requirements for electromagnetic compatibility (EMC).

However, there is no one standard specific to all germicidal products. As the industry evolves, various standards development organizations (SDOs) actively establish standards to address safety and performance requirements for this technology.

Currently, germicidal products can be certified using the best applicable global standards, based on the specific application and installation method. That includes:

  • UL 1598/CSA C22.2 No. 250.0 for fixed luminaires
  • UL 153/CSA C22.2 No. 250.4 for portable luminaires
  • UL 507/CSA 113 for fans and air cleaners
  • UL 867/CSA 187 for electrostatic air cleaners
  • UL 61010-1/ CSA C22.2 61010-1 for laboratory equipment
  • UL 1993/CSA C22.2 No. 1993 for self-ballasted lamps

For each of the standards identified above, it is necessary to perform a photobiological test according to the IEC 62471 and IES RP-27 standards to identify the applicable UV risk group.

These standards and their requirements should be on top of engineers’ minds during the design phase to ensure that the products comply and won’t have to be redesigned or remade. It can save both time and money during the development process and get products to market quickly and efficiently.

Because there is no one standard specific to these products, manufacturers will need to work with their internal and third-party testing teams to put together a testing plan to assess safety for these products. A well-rounded program should include:

  • Preliminary design review and risk assessment to determine if the design of the product addresses potential UV radiation risk. This step will also consider any safety parameter—occupancy, motion, or similar sensors—used and the certification of such devices.
  • Photobiological testing that determines UV irradiance levels and applicable UV risk hazards.
  • Safety testing, including typical product safety assessments, which can vary by product type. Testing is based on both normal and single-fault conditions.
  • Reports and factory surveillance, which includes on-going factory inspections, must verify that products are made as the original sample tested.

Performance considerations

Performance considerations of germicidal products are also critical. First and foremost, manufacturers need to ensure that they can support product claims. In this case, throughout the design process, it is vital to ensure that the product does, in fact, target and kill the organisms. It might mean producing and assessing a product to industry specifications, or creating your own criteria and requirement to apply to your product.

Furthermore, it’s important to consider other performance factors sought after by end-users, such as energy efficiency, usability, durability, environmental sustainability, material use, and usability. Once you have decided which factors are important to you, your customer and your end product, you will need to identify the best way to ensure your products meet them. It could mean using specifications and requirements set by SDOs or creating your own benchmarks to meet.

Once manufacturers identify what they want their products to do and what criteria they want them to fit into when it comes to performance, they need to use them to develop the product. As with safety, these factors should be used from the start of a product’s development and baked into the design, production, and certification processes.

Ozone emissions

Some germicidal products create ozone; one of their traditional uses is to generate ozone for water disinfection. However, while their intended use is for air purification or surface disinfection, ozone creation can still be undesirable and problematic and strict regulations are in place related to ozone emissions.

While ozone is a naturally occurring substance, if inhaled beyond acceptable limits, ozone can be detrimental to a person’s health. Ozone exposure most severely impacts people with respiratory conditions such as asthma. However, healthy individuals may also have effects such as shortness of breath, irritated lungs, and chest pains. In recent years, the California Air Resources Board (CARB), Environmental Protection Agency (EPA), CDC, FDA, OSHA, and more organizations have announced restrictions for ozone.

Given the concerns and regulations surrounding ozone emissions, manufacturers must design their products to meet these requirements. First and foremost, understand that products should abide by the UL 867 concentration limit of 0.05 parts per million or less. As a product is developed, assess it regularly to ensure it complies with ozone requirements and includes mitigation measures to reduce ozone output. Have your products tested and consider certification illustrating low ozone emission, which signals to the industry and customers that the mitigation measures are in place for the product.

For all of these considerations, a design evaluation can help determine the performance and safety criteria that may apply to your specific product. A testing plan is also an essential asset, as it will help identify which tests to run, the requirements for compliance, how they will be completed, and which, if any, certifications a product will need.

Test plans depend on the fixture type, intended use, and specific performance expectations. Work with your testing partner to fully assess the product, intended use, environment, and market to build a solid test plan. Additionally, an engineering review should be formulated for each product to determine testing and data collection.

As the world continues to look for new ways to sanitize, disinfect, and fight illnesses like COVID-19 and other infectious diseases, germicidal products play an essential role and offer great potential to any manufacturer willing and able to navigate the design, testing, and certification needs for these products.

It’s important to educate the industry about these products’ needs and align with an expert who understands the space and requirements. Keeping these factors in mind from the start will help ensure a smooth process bringing products to market from concept to market launch and beyond.

This article was originally published on EDN.

Jeff Davis is technical lead for lighting performance at Intertek.

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