A surgical mask is mainly intended to stop the spread of the user’s respiratory secretions, such as droplets. Respirators, such as filtering half masks (FFP) are intended to prevent air impurities from entering the respiration of the user. They also protect from fine airborne aerosols.


The filtration capacity test for FFP respirators is much more demanding than the Bacterial Filtration Efficiency test conducted for surgical masks. The difference in the tests is due to particle size and the flow rate of the test aerosol. The only comparison that can be made between these test results is stating that the even the lightest class of respirators, the FFP1, is required to have a better filtration capacity than any type of surgical mask. An FFP standard respirator is also expected to fully seal against the face. FFP respirators protect from airborne aerosols. Studies show that surgical masks do not protect from aerosols.

Requirements the standard EN 14683 sets on surgical masks


Type I

Type II

Type IIR

Bacterial Filtration Efficiency, BFE, %*




Pressure drop or breathing resistance, Pa/cm2




Splash resistance, kPa

Not required

Not required


Microbial cleanliness, cfu/g

≤ 30

≤ 30

≤ 30

Biocompatibility EN ISO 10993-1**

Required of all types.

* Flow rate of aerosol is 28.3 l/min. Size distribution average is 3.0 mm.

** The product undergoes standardized allergy and toxicity related tests.

Requirements set in the standard EN 149:2001+A1:2009 for filtering half masks or FFP standard respirators





Internal leak rate when worn, must be fulfilled in 46 of 50 individual results, %




Average internal leak rate, must be met by eight out of 10 individual users, %

≤ 22

≤ 8

≤ 2

Filtration capacity of the respirator,
sodium chloride and paraffin oil, %




Inhalation resistance at flow rate of 95 l/min, mbar

≤ 2.1

≤ 2.4

≤ 3.0

Exhalation resistance at flow rate of 160 l/min, mbar




Carbon dioxide content of exhalation, %


≤ 1.0


≤ 1.0

≤ 1.0


The internal leak rate is established using sodium chloride aerosol on test subjects walking at 6 km/h in a test chamber. The internal leak rate expresses the number of particles that enter the mask either through the filter of from its sides, when the user is wearing the mask. The particle size distribution in the test is 0.02–2mm with an average of 0.6mm.

In the filtration capacity test the aerosol flow rate is 95 l/min. The particle size distribution average is 0.6 mm in the sodium chloride test and 0.4 mm in the paraffin oil test.

There are additional requirements for FFP respirators regarding flammability, durability, innocuousness, use instructions, labels and continuous manufacturing oversight.

See also

Respiratory protective equipment (Tukes)

Lisätietoa  viestinta@ttl.fi  

Työterveyslaitoksen ohjeet on tehty yhteistyössä sosiaali- ja terveysministeriön (STM) ja Terveyden ja hyvinvoinnin laitoksen (THL) kanssa. Seuraamme myös Maailman terveysjärjestön (WHO) ja Euroopan tautiviraston (ECDC) julkaisuja.

Euroopan tautiviraston COVID-19-sivut

Maailman terveysjärjestön (WHO) koronavirussivut