SANYO’s Electrolyzed Water Technology Effectiveness Verified

From Joint Research with Tsinghua University
Effectiveness measured for the removal of “Formaldehyde”, achieving indoor air purification

Tokyo.– SANYO Electric Co., Ltd. (SANYO) announces that SANYO and the Department of Environmental Science and Engineering in Tsinghua University (Beijing, China) have completed joint research demonstrating SANYO’s electrolyzed water technology regarding indoor air purification technology and its effectiveness in reliably removing airborne “formaldehyde” for long periods of time, through a specially developed environmental testing lab designed to house low concentration chemical materials to test indoor air purification technology.

“Formaldehyde” is a typical airborne agent and one of thirteen volatile organic compounds for which indoor air quality guidelines are in place due to the effects of the substance on the human body, designated by an investigative committee as a possible cause of “Sick House Syndrome (indoor air contamination as part of a variety of issues that can affect health)”, a problem case established and investigated by the Ministry of Health, Labour, and Welfare (Japan). Since the Building Standards Law was revised in 2003, it is estimated that more recently built homes, offices and other structures are constructed with a lower number of materials containing formaldehyde. However, building materials are not the only items that contain the compound, as furniture and other fixtures such as office equipment, etc. serve as diffusion sources. In order to achieve indoor air quality guideline mandates, it has become even more important to devise and implement testing measures to combat the airborne conditions identical to those of the actual site.
The recent performance test for air purification/cleaning systems for the continuous removal of potentially harmful airborne substances was conducted using the “continuous gas flow mode”, a test method where a variety of airborne compounds and substances are continuously supplied while the conventional test method includes evaluating the attenuation of the virulent substance concentration comparing with its initial concentration typically conducted in hermetically sealed small spaces. The new continuous test method is more suitable for evaluating the performance for removing substances continuously emitted from wallpaper, building materials, and furniture, etc. Specifically, the test is conducted in a large-capacity stainless-steel chamber specially designed to keep constant temperature and humidity while low-concentrations of formaldehyde gas were continuously supplied. The performance of the air purification systems was evaluated for sustained removal of the airborne chemical by measuring the systems’ exhaust concentration.
The results demonstrated that the formaldehyde gas removal method using active carbon filtration as typically found in a common, general air cleaner worked for a short period of time, although the stable air would become contaminated again soon. However, the air purification element mounted on SANYO’s “VW-VF10B” commercial use air purification system was shown in the test to not only remove formaldehyde from the air, but that it was also able to keep the air cleaner and safer for a longer period of time.

The recent study results were presented at the Chinese Society For Environmental Sciences Symposium held on December 2 in Shenzhen, China by Tsinghua University under the title of “Evaluation of VW [virus washer] air cleaner to remove formaldehyde by continuous mode”.
Outline of the environmental lab used for low concentration chemical material testing

This environmental test lab was specially designed by Tsinghua University. In a large-capacity stainless steel chamber having an overall effective volume of 4.0 m3 with a floor area of 1.96 m2 (1.4 m x 1.4 m) and a height of 2.0 m, gaseous chemical substances and compounds can be reliably and continuously supplied.
As the inner surface of the container is mirror-finished and free of irregularities, suppressing adsorption and desorption of the airborne chemical substances, allowing highly reliable test results to be obtained.

Performance test details for removing “formaldehyde” using air purifiers and cleaners

The conventional method for determining the effectiveness in removing airborne formaldehyde was to fill a chamber with high concentrations of the compound (3mg/m3) and determine how long it took to obtain concentration levels within the prescribed guidelines. It is extremely rare, however, to detect more than a 1 mg/m3 concentration level of airborne formaldehyde in actual building environments, and is necessary to point out that the “formaldehyde” diffusion mechanism is also assumed to be continuous. Consequently, SANYO and Tsinghua University concluded that the durability of formaldehyde removing performance reaching a value closer to the guideline concentration was an important indicator for measures to prevent sick house syndrome.
The tests showed that the air purification/cleaning done by the active carbon filtration, a typical formaldehyde removal method, rapidly deteriorated over 20 hours after the system had been in operation, and after 25 hours, the air had completely returned to beyond pre-filtration concentration levels. In comparison, SANYO’s “air purification element” found in its commercial-use air purification system, the “VW-VF10B”, was found to reliably remove formaldehyde from the air over long periods of time.

Test method:
Air with formaldehyde concentrations of 0.5mg/m3 is inserted into the environmental testing room equipped with the air purification system to be tested via a special air intake until it reaches 10m3/hr. Once the air has been processed by the air purification system, the processed exhaust air is then tested and measured to find the concentration of the airborne formaldehyde gas.
Comparative test:
Active carbon container (active carbon mass: 775 g) + air pump