SidePak AM520

Real Time Changes What the Measurement Is For

Traditional respirable dust measurement clips a filter to a worker, runs it for a shift, and sends it away for gravimetric analysis. The result arrives days later as one number for the whole shift.

That number tells you whether the shift averaged above the limit. It tells you nothing about what caused it. By then, the task has been repeated, and any control decision is based on a guess about which part of the day produced the exposure.

The SidePak AM520 measures continuously and displays as it goes, so the record is a trace rather than an average. It shows which task, which part of the shift and which location produced the dust, which is the information a control decision actually needs.

It also warns the person wearing it. A 95 dBA audible alarm, a blinking red LED and a flashing red display mean an exposure can be acted on during the shift, rather than reported after it. Alarms can be set as general or STEL alarms, with levels from 0.001 to 999 mg/m³.

Calibrating for the Dust You’re Measuring

The AM520 is a photometer. It works out mass from scattered light, and the relationship between the two depends on the particle size, shape and density of the dust being measured.

It’s factory calibrated against the respirable fraction of ISO 12103-1 A1 test dust. For accurate readings on a particular site’s dust, TSI’s manual sets out how to develop a photometric calibration factor: run the AM520 side by side with a gravimetric sampler, compare the results, and enter the new factor into the instrument. TSI provides application notes for doing this for respirable silica and for diesel particulate matter.

Up to five user defined calibration factors can be stored, with labels, so the instrument can be switched between materials and sites. That’s the point worth understanding rather than glossing over: the AM520 is accurate when the calibration factor is right for the dust, and misleading when it isn’t.

Inlet Conditioners Set What You’re Measuring

The size fraction the AM520 reports is set by the inlet fitted, not by the electronics.

Changing the inlet changes the instrument’s job. One unit can cover respirable dust monitoring one day and diesel particulate in a workshop the next.

The flow rate is user adjustable up to 1.8 L/min, and the cyclones need it set to 1.7 L/min to give the correct cut point.

How It Measures

A 650 nm laser diode is directed at the aerosol stream drawn through the instrument. Light scattered by the particles is collected at 90 degrees to the beam, and the intensity of that scattered light is a function of the particle concentration.

That gives a range from 0.001 to 100 mg/m³, across particle sizes from 0.1 to 10 microns, with a minimum resolution of 0.0001 mg/m³.

Personal Monitoring, Not Area Monitoring

The AM520 is designed to be worn on a person for a shift. It’s rated IP54, protected from limited dust and water spray, and works from 0 to +50°C.

For continuous unattended monitoring at a boundary or fence line, area monitoring is the better fit, and AQMesh is one option. Used together, they answer different halves of the same question: personal monitoring shows what one worker breathed, and area monitoring shows what the space contained and where it came from.

Data and Software

The AM520 logs about 80,000 data points (55 days at one reading a minute), with logging intervals from 1 second to 30 minutes. It’s operated by push buttons, or programmed through TSI’s TrakPro v5 software over USB.

Where It’s Used

Mining. Foundries. Construction sites. Chemical plants. Refineries and petrochemical plant. Power and utilities. Transportation. Aerospace. Maritime. Confined space work where dust is the hazard. General industry and occupational hygiene surveys.