TÜV NORD CERT is a notified body for the certification of particle filtering half masks (CE 0044). In its laboratory for mask testing of DMT (TÜV NORD subsidiary), it has carried out comparative measurements with regard to the penetration test according to EN 149 (respectively EN 13274-7) in cooperation with Palas®, a manufacturer in test stand and measuring equipment.
The aim: to ensure that the measurement results of the PMFT 1000 M test stand (Palas®) are comparable to those of a notified body (EN 149 compliant test). The PMFT 1000 is used by mask producers for quality assurance.
Test stand PMFT 1000 M from Palas®
What was tested
Three different, randomly selected masks from various manufacturers were tested on the two test systems in the TÜV Nord laboratory. According to the manufacturer, all masks had an FFP2 or KN95 classification. Testing was performed for each mask using both salt and paraffin oil as the test aerosol. Several specimens of each batch were measured to determine the mask’s spread. Each mask was used only once in order to exclude the influence of loading effects on the penetration value.
These are the results
Figure below shows the results of the measurements with NaCl as test aerosol. The medium penetration of all tested specimens and the respective standard deviation are shown. Measurements that fall outside the standard deviation are shown as error bars and indicate the minimum or maximum penetration measured.
Results of the comparative measurements with NaCl as test aerosol. The mean value and the standard deviation per mask for the measurement on the PMFT 1000 M and TÜV NORD’s own test rig are plotted. Measurement results outside the standard deviation are shown via error bars.
Figure below shows the results of the measurements with oil as test aerosol. An evaluation adapted to TÜV NORD’s laboratory measurement procedure (DMT) was used to calculate the penetration from the PMFT measurement data.
Results of the comparative measurements with oil as test aerosol. The mean value and the standard deviation per mask for the measurement on the PMFT 1000 M and TÜV NORD’s own test rig are plotted. Measurement results outside the standard deviation are shown via error bars.
In summary, the comparative measurements have shown that the measured penetrations on the PMFT 1000 M agree very well with the results of the TÜV NORD respirator testing laboratory (DMT).
Palas® PMFT System for Respiratory Mask Testing
Advantages:
· Test rig working principle meets EN 149/NIOSH/GB 2626/ASTM F2299-3/ASTM F3502-2021/CWA 17553
· Testing of fractional efficiency, e.g., efficiency in the whole size range of 100 nm up to 40 µm
· we have 32 size channels to do accurate analysis of filter and filter mask efficiency for Corona Virus (size approx. 120 nm up to 160 nm) in the size range between 100 nm and 3 µm
· Future proof: Works with any kind of aerosol without adjustments
· Further measurement of differential pressure, e.g., as well within different face velocities
· Face velocity adjustable between 1.5 – 50 cm/s
· The product capable of fast quality assurance and continuous optimization in R&D (display of size distribution)
Applications:
· Test of respiratory masks
· Exact analysis of filter mask efficiency for e.g., COVID
· Filter testing for HEPA quality
Palas® China will participate in the Asia Nonwovens Exhibition and Conference combined with the 19th Shanghai International Nonwovens Exhibition at the Shanghai World Expo Exhibition and Convention Center from July 22nd to 24th, 2021. Palas® will bring a variety of instruments to the exhibition, including the respiratory mask filter test rig PMFT 1000 series which are capable of accurately analysis of filter mask efficiency, the MFP series of filter material testing solutions for automotive air filters, air conditioning filters and filters for general ventilation equipment, as well as the aerosol spectrometer system Promo® series for continuous measurement of particle size analysis and concentration determination. Please visit Palas® at booth 1J10.
