EN 149 ndi muyezo waku Europe woyesa ndikuyika chizindikiro pakusefa theka la masks. Masks oterowo amaphimba mphuno, pakamwa ndi pachibwano ndipo amatha kukhala ndi ma valve opumira kapena / kapena mpweya. EN 149 imatanthawuza magulu atatu a masks omwe ali ndi theka, otchedwa FFP1, FFP2 ndi FFP3, (komwe FFP imayimira kusefa nkhope) malinga ndi kusefa kwawo. Imayikanso masks kukhala 'ntchito imodzi yokha' (yosagwiritsidwanso ntchito, yolembedwa kuti NR) kapena 'yotha kugwiritsidwanso ntchito (yopitilira kusuntha kumodzi)' (yomwe ili ndi R), komanso chilembo chowonjezera cha D chikuwonetsa kuti chigoba chapambana mayeso otseka pogwiritsa ntchito fumbi la dolomite. Zopumira zamakina zotere zimateteza ku mpweya wa tinthu tating'ono monga fumbi, madontho, ndi ma aerosols.
