Vihelm is FDA-certified and meets the ISO 13485:2016 Standard of Quality Management for Medical Devices. Vihelm is also certified by Vietnam’s Ministry of Health.
Vihelm’s products were independently tested by the Key Laboratory of Advanced Material for Green Growth, Vietnam National University. Vihelm has 100% PM2.5 filtration efficiency. CO2 buildup in the breathing zone is 2,471 ppm (0.2471%) while the temperature and humidity inside only see a slight increase.
Particulate Matter and Particle Size Testing
The efficiency of PM2.5 dust purifying in a situation went up to 100,00% in 40 continuous tests. The test has shown that when the PM2.5 concentration outside is 145,296 particles/m3, the level inside Vihelm is 0.
|No.||Measurement||Unit||Average value (No. of tests = 40)|
|1||PM0.3 concentration inside the helmet||particles/m3||24,638,386|
|2||PM0.3 concentration outside the helmet||particles/m3||178,223,945|
|3||PM1 concentration inside the helmet||particles/m3||9,183|
|4||PM1 concentration outside the helmet||particles/m3||946,583|
|5||PM2.5 concentration inside the helmet||particles/m3||0|
|6||PM2.5 concentration outside the helmet||particles/m3||145,296|
Low CO2 build-up
The concentration of CO2 was only 2471 ppm (0.2471%), much lower than 6 others respirators published in another research on CDC website in the US.
The respirators in the research have the CO2 concentration from 5,500ppm to 11,700 ppm, over than the permitted level of the US National Institute for Occupational Safety and Health (NIOSH), however, the CO2 concentration of these respirators is still much better than the CO2 in medical masks. In a recent published research, the CO2 concentration in medical masks goes up to 14162 ppm
Thanks to Vihelm’s powerful blower which continuously pumps 27.86 cubic feet of fresh air per minute into the breathing zone, the CO2 build-up inside Vihelm headgear is kept at 2,471 ppm (part per million).
|No.||Measurement||Unit||OSHA ’s Permissible Exposure Limit over an 8-hour work day||Average value|
(No. of tests = 40)
|1||CO2 concentration inside the helmet||ppm||5,000||2,471|
|2||CO2 concentration outside the helmet||ppm||413|
Temperature and Humidity
With Vihelm, thanks to our 9-CFM blower, the air in the headgear constantly moves and provides a feeling of coolness. When test participants put on Vihelm and walk around indoors, the difference in temperature and humidity inside and outside the helmet is virtually unnoticeable: an increase of 0.3°C (0.54°F) in temperature and 6% in humidity. With N95 respirators, the temperature rises by 4.5°C (8.1°F)
|No.||Measurement||Unit||ASHRAE’s limit SS 2010||Allowed limit TCVN 5508:2009||Accuracy||Average value ± standard deviation(No. of tests = 40)|
|1||Temperature inside the helmet||°C|
20 – 26
18 – 32
|± 0.6°C||25.5 ± 0.6|
|2||Temperature outside the helmet||°C||± 0.6°C||25.8 ± 0.6|
|3||Humidity inside the helmet||%|
30 – 65
40 – 80
|± 3%||55.0 ± 3.8|
|4||Humidity outside the helmet||%||± 3%||48.5 ± 4.1|