There continues to be a dispute about whether a face shield (sometimes called a “visor”) is as effective or more effective than a face mask. Frankly, I do not understand why. Face shields will not protect someone from airborne Covid-19 – period. A face mask must always be worn with a face shield. This is … More
Articles
Using Filtration, Ventilation and Differential Pressure to Slow the Spread of Covid-19
By Jim Rosenthal, CAFS As of today, August 8th, US health officials have reported nearly 5,000,000 cases of Covid-19 (officially SARS-Cov-2). Deaths are over 161,000. This is not just the flu. One of the reasons the disease has spread so fast and so widely is within-household transmission. It is estimated that one in five people … More
How a MERV 13 Air Filter and a Box Fan Can Help Fight Covid-19
By Jim Rosenthal, CAFS A MERV 13 filter and a box fan? It is definitely not a new idea. It has been floating around for years. However, in the era of Covid-19, it is time to take all of the tools out of the toolbox. This simple, inexpensive air cleaning device can remove substantial amounts … More
The Adventures of “Hairy Manne” or Why you should always wear a face mask with a face shield – Continued
(Caution: Wearing a face shield without a mask could be hazardous to your health) By Jim Rosenthal July 14, 2020 – Canton of Graubunden, Switzerland Local health officials spoke out against face shields. In a recent Covid-19 outbreak at a local hotel all of the employees who were infected had been wearing face shields without … More
Understanding How HEPA Air Filters Remove Covid-19 From the Air
By Jim Rosenthal, CAFS “HEPA filters remove particles down to 0.3 microns. COVID-19 viruses are 0.125 microns so a HEPA filter cannot remove them from the air.” The above statement is often found in news articles about COVID-19. It is WRONG! HEPA filters remove over 99% of 0.125 micron sized particles! Even in well researched … More
Does Reducing PM2.5 in Air Pollution Lead to Better Health Outcomes?
Higher levels of PM2.5 have been shown to cause negative cardiovascular and respiratory health effects. Consequently, commercial and residential standards are being set to reduce PM2.5 exposures with the intent of improving health outcomes. This may or may not be a valid approach. Here’s why: All PM2.5 is not the same. The negative health effects … More
AHRI Recommends Not to Withdraw ASHRAE 52.2 in Favor of ISO 16890
In a letter to the ASHRAE 52.2 Standard Setting Project Committee, the Air Conditioning, Heating and Refrigeration Institute (AHRI) has recommended not to adopt ISO 16890 as the air filter test standard for the United States. AHRI is a trade organization whose members produce over 90% of the residential and commercial heating, cooling, water heating, … More
Efforts to Include International Standards in ASHRAE 62.1 Illustrate Problems of ISO16890
ASHRAE has been involved in a concerted effort to include references to international standards in ASHRAE Standards. The purpose is to provide consistency across borders and simplify international construction and building operations. A case in point is the proposed addition of provisions of ISO 16890 into ASHRAE 62.1-2016. Unfortunately this can lead to problems. Of … More
Analysis Shows ISO 16890 Uses Outdated and Inaccurate Particle Distribution Data
In a recent paper entitled “Evaluating the Sensitivity of the Mass-Particle Removal Calculations for HVAC Filters in ISO 16890 to Assumptions for Aerosol Distributions” the author, Dr. Brent Stephens of the Illinois Institute of Technology, found that the particle distribution data used in ISO 16890 was outdated and inaccurate. The paper was published in the … More
ASHRAE 62.2 and ISO 16890 – Not a Good Fit
A recent development affecting the air filter industry is the addition of Addendum k to Standard ASHRAE 62.2-2016 (Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings) to include air filter classifications from International Standard ISO 16890. The purpose is to add “an alternative method providing PM2.5 efficiency data” to the ASHRAE 52.2 MERV … More