Iso & Lab Certified – Vihelm

Iso & Lab Certified

Vihelm meets ISO 13485:2016 Standard of Quality Management for Medical Devices.

Lab – Certified

Vihelm was already proved its effectiveness in the independently lab of Vietnam National University with percentage of PM2.5 dust purification is 100,00% in its best condition, and the concentration of CO2 is 2,471 ppm (0.2471%), much better than other respirators. The detailed information is as follows: the efficiency of purifying small-sized dust, the concentration of CO2, temperature and humidity.

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. MeasurementUnitAverage value (No. of tests = 40)
1PM0.3 concentration inside the helmet particles/m324,638,386
2PM0.3 concentration outside the helmetparticles/m3178,223,945
3PM1 concentration inside the helmet particles/m39,183
4PM1 concentration outside the helmetparticles/m3946,583
5PM2.5 concentration inside the helmet particles/m30
6PM2.5 concentration outside the helmetparticles/m3145,296

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. MeasurementUnitOSHA ’s Permissible Exposure Limit over an 8-hour work day Average value
(No. of tests = 40)
1CO2 concentration inside the helmet ppm5,0002,471 
2CO2 concentration outside the helmet ppm413 

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 (32.5°F) in temperature and 6% in humidity. With N95 respirators, the temperature rises by 4.5°C (40.1°F)

No.MeasurementUnitASHRAE’s limit SS 2010Allowed limit TCVN 5508:2009Accuracy Average value ± standard deviation(No. of tests = 40)
1Temperature inside the helmet °C 

20 – 26

18 – 32
± 0.6°C25.5 ± 0.6
2Temperature outside the helmet°C ± 0.6°C25.8 ± 0.6
3Humidity inside the helmet%

30 – 65

40 – 80
± 3%55.0 ± 3.8
4Humidity outside the helmet %± 3%48.5 ± 4.1
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