Environmental monitoring

We carry out environmental surveys in both outdoor and indoor environments, including sampling, analysis, and consultancy. We are accredited for measurements of emissions to air, and determination of a variety of emission parameters and components. We also perform environmental surveys of buildings, indoor climate and occupational hygiene.

Air tightness testing of respiratory face masks

Nemko Norlab offers air tightness testing of respiratory face masks for health professionals and industrial workers who needto be protected against exposure to for example Covid-19, dust, quartz, organic solvents, or welding fumes.

We follow the protocol for air tightness tests of masks developed by HSE in UK (Health and Safety Executive). We have proven routines for conducting such air tightness tests in a situation with Covid-19.


Is your mask adapted to your face?

Air tightness testing of respiratory face masks is a method for checking that a mask is adapted to the shape of the user’s face, and that good air tightness is ensured. For such mask to function, both good fit and correct usage are required.

Solveig Føreland (UNN – Arbeidsmedisinsk avd. Universitetssykehuset Tromsø), Marit-Kristine Tangvik (Nemko Norlab, measurement technician) og Lilian Karlsen (Nemko Norlab, occupational hygienist). Nemko Norlab may conduct the test at client site, in an appropriate office.

An airtightness test will measure and detect possible leakage between face and mask

Facial shape, hair / facial hair, scars, and fat may impact the fit between face and mask.

Examples of facial shape:

[Z Zhuang and B Bradtmiller] http://www.cdc.gov/niosh/npptl/topics/respirators/headforms/ ISO 16976-2 Respiratory Protective Devices — Human Factors — Part 2: Anthropometrics

During such test, the user will also be given guidance regarding usage of such protective masks (including putting on and taking off such mask). One will also discuss the consequences of using a mask with poor fit. 

About the test

The test is conducted with a particle counter that counts particles inside and outside the mask. Then number of particles inside the mask is compared with the number of particles outside the mask, and an airtightness factor is calculated. The test person conducts standardized movements during the test. If it is not possible to obtain a good fit between the mask and the face, other masks (manufacturer, size) should be considered. If still not possible to obtain good fit, other types of respiratory protection should be considered. An airtightness test will typically take 30-60 minutes, depending of on the number of masks tested.

Masks must be tested for airtightness

  • Some masks fit many face shapes.
  • Some masks fit many face shapes.
  • Everybody using a mask should do airtightness testing to ensure good fit between mask and face.

Source: Føreland et al., 2019


To protect health professionals, testing of airtightness of protective masks should be part of the routines of health service organizations.

The employer is responsible for providing appropriate protective masks for its employees, depending on the nature of the work to be conducted, type of pollution, and level of exposure.  Protective masks shall be adjusted to the individual employee.

Do not hesitate to contact us for questions or clarifications.


Lilian Karlsen

Lilian Karlsen

Occupational Hygienist

Work environment, indoor climate

 +47 984 21 192

Tove Ravnåmo

Tove Ravnåmo

Senior Advisor / Occupational Hygienist

Work environment and indoor climate, noise measurements

 +47 990 36 032