Looking After Your PortaCount When Fit Testing

Looking after your PortaCount when Fit Testing

Your PortaCount is an expensive piece of equipment, and it is vital to meeting your fit testing needs. As such, it is important to look after your PortaCount to ensure it can continue to function appropriately and minimise disruptions to your business.

This blog post should assist in providing a basic guide to looking after your PortaCount. This post is general advice only, if in doubt or wish to seek additional information, see your PortaCount Operation/User manual for specific guidance.

A well maintained PortaCount will ensure your fit testing is compliant, reliable and accurate.

Maintenance and Calibration

TSI recommends annual recalibration and cleaning by the manufacturer. Be aware that all repairs on your instrument must be conducted by a qualified factory-authorised technician. In Australia we would recommend Kenelec Scientific for all servicing and calibration.

Calibration may seem expensive but it is a worthwhile investment to make sure that your unit is running correctly.

Preventative Maintenance

High Particle Concentrations:

The “High concentration message” refers to exposure to ambient concentration levels higher than recommended, which may degrade the performance of the instrument over time. If this occurs, minimise and reduce ambient particle concentration by turning off/ turning down nearby particle generators, ensuring they are the appropriate distance away (1.8m), increasing room ventilation, or conducting fit testing in a different location.

Ideally when fit testing N95 respirators we aim for between 100-800 particles, and for Non N95 testing we aim between 2000-8000 particles. We find fit testing in smaller rooms/in our fit test vans easier to control the ambient count, than a larger room or hallway.

Alcohol cartridge:

To avoid damage to the instrument or unreliable results, ensure the alcohol used on the wicks is 99.5% pure or greater purity reagent grade isopropyl alcohol, such as that sold by the manufacturer. We would only ever recommend using TSI alcohol.

The wicks should be changed if it is contaminated or if moisture accumulates in it. See the relevant user manual for instructions on replacing your alcohol wick.
We have a set frequency for changing wicks and find this has worked well over the years.

Alcohol cartridge cavity:

To avoid plugging the small internal nozzle and potentially preventing operation of the instrument, keep dirt and lint out of cartridge cavity, and cover the cavity with the storage cap when not using or transporting the instrument.

Usually if testing in a clean environment this should not be an issue, but we have heard that for fit testers testing outside on a construction site (incorrectly), this can be an issue.

Looking after your PortaCount when Fit Testing

Connection ports:

Always be gentle when plugging in or removing anything from the connection ports and be careful that nothing is ripped/pulled as this could be costly and result in downtime.

Taping Down Twin Tubes:

When fit testing, it is not uncommon for the worker being fit tested to move away from the PortaCount and pull the twin tubes. We would always recommend taping down the PortaCount twin tubes to the table, this acts as a safeguard and prevents your PortaCount being pulled off the table.

Looking after your PortaCount Fit Testing

Blocked tubes:

If the twin tube assembly is kinked or pinched, this may restrict airflow into the instrument. Blockage can occur with adaptors so always double check that the blockage is not within the adapter. If a blockage does occur you will hear a groaning/labouring sound- this is a good indicator to stop the test and remove the twin tube from the adaptor and find the blockage.

Usually during annual calibration the twin tubes are replaced, this should minimise this issue but always make sure that the twin tubes are in good condition and not twisted/blocked prior to using.

End of Twin tubes Stretching:

After fit testing for a while the ends of twin tubes can become stretched and slip off the probe during testing, this can easily be rectified by using a pair of scissors to cut 5mm from the end of the tube.


Take care when handling- your PortaCount may weigh up to 3.1kg. It is important that you take care when handling the instrument to avoid dropping or otherwise bumping it and causing damage.


Nozzle Cleaning:

A clogged internal nozzle may cause a low ambient count and failed tests. This can be resolved by two procedures, both performed with the instrument turned off. You may use clean compressed gas with a long nozzle to apply short bursts of gas to the nozzle, or drip small amounts of alcohol to the nozzle through the cartridge cavity. See User Manual for details of these procedures before performing. 

Twin Tube Cleaning:

Moisture from a subject’s breath may create condensation on the inside of the tube. To remove this and avoid moisture entering the instrument, an operator may turn off the instrument, detach the clear sample tube from the corresponding inlet fitting and HEPA filter, and use clean compressed gas blowing away from the instrument to expel any built up moisture into a disposable paper towel, before reattaching the sample tube to the HEPA filter and inlet fitting.

Looking after your PortaCount when Fit Testing

Storage and Unsafe Environments

Operate in a clean area:

Operate and store your PortaCount in a clean area, away from corrosive or acidic contaminants. Operating in close proximity to sources of dust/smoke may affect the unit.

Operating your PortaCount in high humidity environments may cause the “Low Alcohol” message to appear sooner than normal and the wick may need to be replaced or dried as per the user manual.

Operating or storing your PortaCount in non-ideal temperatures may cause damage to the instrument. See your User Manual for the specific temperature range for your instrument.

Electrical protection

Use only the AC adapter provided with your PortaCount and always ensure the power supply/electrical cables are tested and tagged. For us in Brisbane, QLD we usually have all equipment tested every 6 months.


Never ship with alcohol cartridge inserted, which may flood the optics. We would recommend shipping the unit in a hard black box, and ensuring that it is bubble wrapped and secure. You may also want to add n air tag/smart tag so you can track the unit.

Useful Links

There is a huge amount of information out there to help you look after your PortaCount, some including:


We have been completing fit testing in Brisbane since 2015 and have only ever used the PortaCount 8038 or 8048. We have found these units extremely high quality, highly reliable and accurate.

For all maintenance/cleaning/storage and use, the best source of information is the Manufacturers Specifications.

We can assist with all your fit testing and RESP-FIT training needs. Get in contact with us by either calling 1300 336 003 or via our contact page.