Cartridge Service Life Calculator

Work out cartridge service life instantly with clear inputs, formula shown and shareable results.

About Cartridge Service Life Calculator

Cartridge life is sorbent capacity divided by the rate at which contaminant is drawn in. Converting ppm to mg/m³ uses the molar volume of 24.45 litres at 25 °C and one atmosphere, and multiplying by breathing rate gives grams per hour. A change schedule at ninety percent of calculated life provides margin for humidity and concentration variation.

Formulas

Mass concentration

mg/m³ = ppm x molecular weight / 24.45

Service life

Hours = sorbent capacity g / (mg/m³ x m³ per hour / 1000)

Worked example

With the default values below, Cartridge Service Life Calculator returns Estimated service life of 44.29. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cartridge sorbent capacityminimum 0.1 g: 30 g
Contaminant concentrationminimum 0.1 ppm: 100 ppm
Molecular weightminimum 1 g/mol: 92 g/mol
Breathing rateminimum 1 L/min: 30 L/min

Results

Estimated service life: 44.29 h
Change schedule with safety margin: 39.86 h
Contaminant uptake rate: 0.6773 g/h
Mass concentration: 376.3 mg/m³

Step by step

1Values used
2Mass concentration
3Service life
4Estimated service life= 44.29 h
5Change schedule with safety margin= 39.86 h
6Contaminant uptake rate= 0.6773 g/h
7Mass concentration= 376.3 mg/m³

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Preliminary estimate only. Cartridge change schedules must be established using the manufacturer's breakthrough data or a validated model as part of a written respiratory protection programme.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Preliminary estimate only. Cartridge change schedules must be established using the manufacturer's breakthrough data or a validated model as part of a written respiratory protection programme.

Frequently Asked Questions

How is the Cartridge Service Life figure worked out?

mg/m³ = ppm x molecular weight / 24.45. Cartridge life is sorbent capacity divided by the rate at which contaminant is drawn in.

Why does humidity shorten cartridge life?

Water vapour competes for adsorption sites on the activated carbon. Above about sixty-five percent relative humidity, breakthrough time can fall by half.

What values do I need to enter?

This calculator takes 4 inputs: Cartridge sorbent capacity, Contaminant concentration, Molecular weight, Breathing rate. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.