The webinar featured CASPR Technologies, one of our partners in Colorado, and focused on explaining how CASPR systems work, how they differ from traditional indoor air quality (IAQ) solutions, and how they align with emerging industry standards, particularly ASHRAE 241.
CASPR is an acronym for Continuous Air and Surface Pathogen Reduction, and the core of the technology is designed to actively reduce airborne and surface-level pathogens in occupied indoor spaces. The CASPR device uses a proprietary light source similar to ultraviolet light, but operating at a unique wavelength. This light is housed within a four-sided honeycomb matrix that is coated with a proprietary catalyst. When the light interacts with this coating, it converts ambient oxygen and water vapor into gaseous hydrogen peroxide (H₂O₂).
The system generates hydrogen peroxide at concentrations between 0.01 and 0.04 parts per million, which is significantly below the OSHA exposure limit of 1 part per million. This concentration is described as only slightly higher than what naturally exists in outdoor environments. Hydrogen peroxide is characterized as nature’s disinfectant, and at these levels it is considered safe for continuous use around people, plants, and pets.
Because hydrogen peroxide is produced as a gas, it disperses throughout the entire volume of the space served by the HVAC system. When installed on the supply side of ductwork, the gas fills the occupied area, allowing CASPR to treat not only the air but also exposed surfaces such as desks, walls, doors, and equipment. This is presented as a key differentiator from traditional filtration and UV-based solutions, which are passive technologies that rely on pathogens physically passing through a filter or remaining in the line of sight of a UV lamp for sufficient dwell time.
CASPR is described as an active technology, meaning it continuously pushes oxidizers into the space rather than waiting for contaminants to reach the device. The system operates 24/7 and continues producing hydrogen peroxide even when the air handler is off. If airflow is stagnant, the hydrogen peroxide naturally reverts back into oxygen and water due to its instability, preventing buildup.
The presenter then reviewed CASPR’s commercial product offerings, including duct-mounted units available in 6-inch, 9-inch, and 14-inch sizes, as well as a ceiling-mounted “Blue Tile” unit designed to fit into standard ceiling grids. Duct-mounted units are sized based primarily on square footage, with occupancy type and airflow also playing important roles. For example, a 14-inch unit can cover approximately 5,000 square feet in a typical office environment, but only about 1,250 square feet in a hospital due to higher pathogen loads. The Blue Tile unit is intended for spaces without centralized ductwork or where visual reassurance is desired, such as reception areas, and covers approximately 2,500 square feet. Electrical input ranges from 120 to 277 volts, and power consumption is approximately 30 to 60 watts.
A major portion of the webinar focused on ASHRAE Standard 241. This standard was developed rapidly at the direction of the White House in response to pandemic conditions and is intended to provide guidance for infection risk management during elevated disease transmission events. ASHRAE 241 is notable for being the first ASHRAE standard to formally acknowledge pathogens as an indoor air quality concern, expanding beyond traditional metrics like VOCs and particulates addressed in ASHRAE 62.1.
ASHRAE 241 establishes standardized testing protocols for air-cleaning devices, requiring both safety and efficacy testing. Safety testing includes four pass/fail criteria: ozone generation (CASPR meets CARB and UL 2998 zero-ozone requirements), secondary chemical byproducts, particulate generation, and noise levels. Secondary byproduct testing evaluates whether the device creates harmful compounds when common chemicals such as amines are present, and noise is evaluated to ensure devices are not so loud that occupants disable them.
For efficacy testing, CASPR was evaluated using MS2 bacteriophage, a non-enveloped virus chosen because it is more difficult to inactivate than common viruses such as influenza or COVID-19. Testing was conducted in a 30 cubic meter chamber, exceeding the standard’s minimum requirement, at five air changes per hour, and was performed by an independent third-party laboratory. Results showed over 70% reduction of MS2 within four minutes and greater than 99% reduction within one hour, with testing initiated from a cold start. Additional surface testing demonstrated over 92% reduction of MRSA within 30 minutes.
Further testing showed CASPR’s effectiveness against a wide range of pathogens, including bacteria, fungi, and spores such as Clostridioides difficile (C. diff), with reported reductions exceeding 91%. Prions were noted as the only category not tested, as they cannot be inactivated by conventional disinfection methods.
The webinar also briefly addressed the ASHRAE 62.1 Indoor Air Quality Procedure, noting that CASPR can be included in calculations that allow reduced outdoor air ventilation while maintaining acceptable IAQ, potentially lowering energy consumption. Carbon dioxide remains a limiting factor in these calculations.
Finally, real-world applications and installations were discussed, spanning healthcare, education, athletics, government facilities, correctional institutions, and retail healthcare settings. A notable example highlighted was installation in all CVS Minute Clinics nationwide. A case study from a Georgia school district showed substantial reductions in student absenteeism following deployment of CASPR technology, reinforcing its potential operational and public health benefits.