IRSST - Institut de recherche Robert-Sauvé en santé et en sécurité du travail

CQ Fibres
Fiber Counting Quality Control

Since 1992, the IRSST has had a quality control program for fibre counting with samples originating from different Québec workplaces. According to the requirements of the official counting method, fibre counters must participate in an interlaboratory exchange program using samples that are representative of their industrial activities, thus allowing their efficiency to be verified. Every three months, the participating analysts receive four samples. After three successful consecutive exchanges, based on specific criteria, they receive a certificate confirming their efficiency. This remains in force as long as they participate in the program and meet these criteria. The list of recognized companies and counters available on the IRSST’s website is updated after each CQ Fibres’ round.

Program description

Fibre counting is carried out on mixed cellulose ester membranes mounted on slides in our laboratory and come from sampling done in various Quebec workplaces. The homogeneity and density of the slides have been verified before being used as inter-comparison samples in the program. Samples must be counted in accordance with the IRSST 243-1 method.

Each round will consist of a series of four test slides with densities generally ranging from 100 to 1300 fibres/mm², which are optimal densities based on the official counting method. However, since these samples come from different work environments, some might have a density of less than 100 fibres/mm². Each year, four rounds will be shipped to counters registered in the program to evaluate their performance and/or to obtain their recognition. Once recognized, the counter’s name will appear on the List of recognized counters and companies on the IRSST’s website, at IRSST website.

Performance results will be made available to participating counters by way of CQ Fibres, a secure website accessible to each participant and each company’s or branch’s contact person registered in the quality control program. To ensure the confidentiality of the results, they will not be made available to any other body except upon written request of the counter and/or company.

Each report will include the following data: the results obtained for the counter, the reference values, the lower and upper limits of acceptable performance, and the density ratios illustrated graphically. The performance and progress of the counter in the program will be known to him in this manner. As a reminder, an acceptable performance means success in at least three of the four samples. (see Classification criteria below).

Classification criteria

The reference value for these samples is established from the results of twelve experienced counters having already demonstrated their acceptable performances in various interlaboratory exchanges.

In order to be recognized, a counter must participate and succeed in 3 successive interlaboratory exchanges, in which his or her results must fall between 0,55 and 2,20 inclusively of the target value for at least three (3) samples out of four (4). His or her status is maintained as long as he satisfies these requirements in subsequent rounds.

If two (2) or more of the four (4) results are not acceptable for a round, the counter will have failed the exchange for a first time. Nonetheless, he or she will keep a recognized status but will be under surveillance. Once a participant has failed two out of three consecutive exchanges, he or she will lose their status as a recognized counter. This will put the counter into a transition period (awaiting status), and could regain his or her status after having successfully completed two successive interlaboratory exchanges.

Program registration

After receiving a possible participation confirmation email, the contact person for the company and / or branch has to complete one or the following form. One registration form per branch and per analyst needs to be completed.

Once registered, contact persons and new counters will receive a user name and password to log on to the “CQ Fibres IRSST” web application. New counters must then complete their personal information, specifically:

  • Submit the results of three slides of different known densities that they have counted ten times each, to determine their intracounter relative standard deviation,
  • Provide a description of the microscope and micrometric slide used,
  • Provide a detailed description of training received and the instructor’s name, title and experience (a certificate or attestation issued by a recognized organization will satisfy this criterion),
  • Provide the certificate or a photo of the HSE/NPL MARK III slide used.

After the file has been analyzed and validated by the IRSST, new participants will be notified by email that they are officially registered in the CQ Fibres Fiber Counting Quality Control program.

Any changes to the company or branch during the year (registration changes, counter additions or removals, change of address) must be sent as soon as possible by the contact person for the company or branch to the following email address: [email protected].


Initial registration $200
Initial registration $50
Participation fee
Annual company fee $200
Cost for each participating analyst $100 per round

PAYMENT: At the beginning of the year, an invoice will be issued for the annual fee and participation. A new application or modifications (addition or removal of an analyst) during the year will be subject of a different invoice.

Shipping the samples

We remind you that a round of four slides will be sent to each company (in the contact person’s name) four times a year. The shipment will include a letter with a list of participant counters and the round closing time e,g, the deadline for reporting the results directly in the “CQ Fibres IRSST” web application. The letter will also explain how to return the slides to the IRSST.

Important dates

For purposes of continuous improvement of our CQ Fibres Fiber Counting Quality Control program, the IRSST has organized the shipping of slides by dividing the participants into two groups. The groups have been randomly created to obtain a similar number of counters in each group. Since 2012, companies participate in CQ Fibres in a predetermined group. Note that a counter cannot participate in a round of the other group and that a company cannot change groups.

Here are the schedules for 2018:

Group A

Serial number 2018‑1 2018‑2 2018‑3 2018‑4
Deadline to add a new counter





Samples shipment





Deadline to submit results online





Reports available





Group B

Serial number 2018‑1 2018‑2 2018‑3 2018‑4
Deadline to add a new counter





Samples shipment





Deadline to submit results online





Reports available





Since 2016, any new requests to add a company, branch or counter must be received by the IRSST before the date of deadline to add a new counter at the beginning of the round. No additions may be made while a round is in progress.

If the samples have not been received by the date shown in the above timetable (Sample reception), contact the CQ Fibres team as soon as possible at [email protected]  or by fax at (514) 288-9632.

Proper care and returning the quality control slides

All slides should be kept out of direct sunlight.

The slides must be returned the IRSST no later than the week following the date shown on the second line of the above timetable.

To return the slides, the IRSST laboratories recommend the following procedure:

  • Appropriately seal the box containing the slide with adhesive tape, pack it with bubble wrap and put it in a bubble or padded envelope (using the packaging received originally), before placing it in the envelope provided by the shipper. This way, the slides will be returned to us in good condition.
  • The safe return of the slides is the responsibility of the participants.

The slides should be returned to:

The CQ Fibres Team
Direction des laboratoires (Laboratory Division)
505, de Maisonneuve blvd West,
12th floor Montréal (Quebec) H3A 3C2

Sending results

It is very important for each counter to submit the results before the date shown on of the above timetable (deadline to submit results) to guarantee that their performance will be evaluated. After that date, results that have not been submitted will be considered outliers and the analyst will have failed the round. However, it is possible to obtain an exemption for cause by emailing a written request to [email protected], before the closing date of the round. This exemption, which is valid for one round, cannot apply to two consecutive rounds.

Recognized counters and companies

The IRSST website lists laboratories with counters recognized by the IRSST program. The list of counters is updated at the conclusion of each round, allowing you and your clients to verify the status of fiber counting analysts.

Laboratories and counters list

CQ Fibre - Log in

CQ Fibres Registration

Companies or counters who want to register for Fibre Counting Quality Control must contact the IRSST at [email protected] before filling in and sending the registration form in order to ensure that a place is available.

Registration forms

For more information
  • Silvia Puscasu

    • M.Sc. Chemistry, Certificate in Analytical Chemistry, B.Sc. Chemistry
      Scientific professional
      Laboratory Division
      Phone: 514 288-1551 ext. 304
      Fax : 514 288-9632
      Email : [email protected]
  • Jacinthe Boisvert

  • Louise Racine