Mastering Quantitative Fit Testing

22nd Feb 2023

Your guide to Quantitative Fit Testing

quantitative fit testing

Quantitative fit testing (QNFT) is an advanced method of respiratory mask fit testing. This method helps to ensure your employees have a proper seal therefore providing the highest level of protection. QNFT uses a machine to measure the amount of leakage, which will determine if the employee needs a new or different sized mask. This method is more accurate than qualitative testing and can also be used for other types of respiratory protection, not just masks.

How does QNFT work?

The quantitative method utilises a porta count machine to record a numerical measurement of the amount of the particles inside the mask compared to the particles outside of the mask. The reading on the porta count machine will determine if the mask has an adequate seal with the wearer’s face.

The goal of this process is not only to determine whether or not your respirator fits well on your face, but also whether or not it filters out enough hazardous substances from the air around you.

The first step is determining your needs. If you’re an employer, a QNFT can verify if the respirators being used by your employees are properly fitted and provide adequate protection from harmful airborne particles. If you’re a respirator user, then you may have questions about the duration of the fit test and the cost.

What are the benefits?

  • Accurate fit testing
  • Increased productivity
  • Reduced training costs
  • Improved quality and compliance


Quantitative Fit Testing with Cavity

We will need the relevant information from you:

  • Name
  • Email
  • Telephone number
  • Number of people
  • Date
  • Location

We hold fit testing sessions in our Head Office in Winnersh, Wokingham or one of accredited fit testers can come to you as we cover nationwide. The cost of our fit testing in Head Office is £35 (inc VAT) per person. Prices start at £150 for us to come to you.

Once you have a date in the diary with one of our fit testers, we will send you a booking confirmation email.

This will include:

  • Date
  • Time
  • Location
  • Price
  • Pre fit test instructions.

With fit testing on the quantitative method, these instructions include:

  • Having some form of photographic ID
  • Clean shaven within the mask seal
  • No smoking or vaping 60 minutes before the test
  • No eating or drinking 15 minutes before the test
  • Remove any make up within the mask seal
  • Bring any head worn personal protective equipment and glasses with you.

It is the employer's responsibility in choosing the correct mask and filters for their employee.

On the day of the fit test, our fit tester will need to set up the machine and check the ambient particles in the fit testing room before commencing with the fit test.

Firstly, they will start with a pre fit testing questionnaire.

Secondly, the fit tester will inspect the mask provided. The employer will need to supply the mask and filters which are adequate and suitable for the wearer. Also, a particle filter needs to be supplied for the test. The fit tester will check the mask to see if it is intact and that there are no defects to the mask. The fit tester will then discuss any appropriate training and maintenance for the mask. The mask will be linked up to the machine ready for the fit test.

The fit tester will guide the wearer in how to inspect the mask before every use, put on the mask, how to do the fit check and also how to take the mask off after use.

Once the mask is on and the fit check has been completed, the fit tester will explain the seven exercises of the fit test.

The wearer will be instructed to step forwards and backwards on an aerobics step while completing the seven exercises which are:

  • Normal breathing
  • Deep breathing
  • Turning head from side to side
  • Moving head up and down
  • Counting out allowed backwards from 100
  • Bending at the waist (while standing still)
  • Normal breathing.

The fit test will approximately take about 10 minutes.

Once completed, the fit tester will discuss if the mask was tight fitting and if the seal of the mask prevented any leakages. Finally, the fit tester will issue the wearer with a fit testing certificate.

A fit test certificate is valid for 2 years, unless anything changes e.g.

  • The wearer has any weight loss or gains weight
  • Substantial dental work
  • Any facial changes (e.g., scars, moles, effects of ageing etc) around the face seal area
  • Any new facial piercings,
  • Any change in head-worn personal protective equipment (PPE).

QNFT is the most accurate way to ensure your employees have the correct protection.

The gold standard for respirator fit testing, QNFT is the most accurate way to ensure your employees have the correct protection. This advanced method of respiratory mask fit testing helps you ensure your employees have a proper seal by measuring how much air is leaking into or out of their masks during use. Therefore, it is the best way to ensure your employees can do their job safely.

At Cavity, we make fit testing simple! You can visit our website, email us on  or call us and speak to Lisa on 0118 4023795 or Sarah on 0118 9079875 who would gladly assist you.

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