Camfil launches CamCarb VG engineered molecular filtration solution
STOCKHOLM, Sweden, 12 May 2021: Camfil launched the CamCarb VG engineered molecular filtration solution, which the company described as a robust solution suited for make-up air and recirculation air systems. The primary use of the technology, Camfil said, is the control of acidic gases that are responsible for the corrosion of electronics and electrical equipment in heavy process industries, such as pulp and paper mills; petrochemical refineries; mining and metal refining operations; and wastewater treatment plants. They are also suitable for lighter applications, such as the removal of noxious and odorous fumes generated outside airports, hospital helipads, cultural heritage buildings, and commercial offices located in city centres, Camfil added. The modules can be filled with different types of Camfil molecular filtration media to suit the specific customer application, the company said. There are two standard configurations of CamCarb VG: VG300 and VG440, it said, adding that the VG300 format is best suited for moderate duty (normally make-up air) applications, and the VG440 is best suited for light-duty (recirculation air) applications.
According to Camfil, CamCarb VG filters can be installed in specially designed housings, with options for front-loading, side-loading, or positive-seal side access (PSSA). They can also be used as replacements in housings and track systems produced by other manufacturers, the company said.
The modules are fully welded and constructed without adhesive to eliminate the possibility of off-gassing, Camfil said. They include a unique moulded mesh to allow the use of a full range of loose-fill media without shedding, it said. Many applications will require multiple molecular media to address a range of contaminants. The different media should be deployed in a series of layered modules. This layered approach will provide the highest removal efficiency, the longest life, and the lowest total cost of ownership (TCO), as each media can be changed when it reaches the end of its useful life, it said, adding that a blended-media, on the other hand, requires all the media to be replaced when just a single component has failed.
ASHRAE Epidemic Task Force releases updated Building Readiness Guide
ATLANTA, Georgia, 02 February 2021: With the performance of many HVAC systems in buildings still being evaluated, the ASHRAE Epidemic Task Force has updated its reopening guidance for HVAC systems to help mitigate the transmission of SARS-CoV-2, ASHRAE said through a Press release.
“The Building Readiness Guide includes additional information and clarifications to assist designers and commissioning providers in performing pre- or post-occupancy flush calculations to reduce the time and energy to clear spaces of contaminants between occupancy periods,” said Wade Conlan, Lead, ASHRAE Epidemic Task Force Building Readiness team. “New information includes the theory behind the use of equivalent outdoor air supply, method for calculating the performance of filters and air cleaners in series, and filter droplet nuclei efficiency that help evaluate the systems’ ability to flush the building.”
According to ASHRAE, major updates to the building readiness guidance include the following:
- Pre- or post-flushing strategy methodology: The strategy has been updated to include the use of filter droplet nuclei efficiency, which is the overall efficiency of filter, based on viable virus particle sizes in the air, to assist in determining the impact of the filter on the recirculated air on the equivalent outdoor air. This allows the filter efficiency as a function of particle size, using ASHRAE Standard 52.2 test results, to be estimated based on the expected size distribution of virus-containing particles in the air. This calculation is currently based on Influenza A data and will be updated as peer-reviewed research becomes available for the distribution of particle sizes that contain a viable SARS-CoV-2 virus. Additionally, a chart has been added to help determine the time to achieve 90%, 95% or 99% contaminant reduction, if the equivalent outdoor air changes per hour is known.
- Flushing time calculator: There is now a link to a view-only Google Sheet that can be downloaded for use, to help determine the available equivalent outdoor air changes and time to perform the flush. This sheet is based on a typical mixed AHU with filters, cooling coil, with potential for in-AHU air cleaner (UVC is noted in the example), and in-room air cleaning devices. Provided efficiencies of MERV-rated filters are based on the performance of over 200 actual filters from MERV 4 through 16, but the tool also allows users to enter custom characteristics for specific filters.
- The sheet also calculates the filter droplet nuclei efficiency, based on the cited research but allows a user to adjust the anticipated distribution of virus, as desired. It also allows specification of the zone (room) air distribution effectiveness from ASHRAE Standard 62.1 to account for the impact of the HVAC system air delivery method on the degree of mixing. Default calculations assume perfect mixing. Finally, the tool allows for the target air changes to be adjusted if an owner wants to achieve a different per cent removal in lieu of the recommended 95%.
- Heating season guidance: The guide now includes data to consider for heating of outdoor air and the potential impact on pre-heat coils in systems.
- Adjustments to align with Core Recommendations: The Core Recommendations were released in January 2021, and this guidance document needed to be updated to ensure that the information provided aligned with the intent of those recommendations. This included minimum outdoor air supply and filter efficiency requirements and their role in an equivalent outdoor air supply-based risk mitigation strategy.
According to ASHRAE, the guidance still addresses the tactical commissioning and systems analysis needed to develop a Building Readiness Plan, increased filtration, air cleaning strategies, domestic and plumbing water systems, and overall improvements to a system’s ability to mitigate virus transmission.