Microfibre Release over a Garment Life

The formula

This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.

How the result is derived

Step by step, from the values you type to the figure on screen.

1. The 6 inputs are read from the form on every keystroke: Garment Mass, First-Wash Shedding Rate, Decay per Wash, Washes in the Garment Life, Filtration Efficiency and Garments Produced per Year.
2. Each value is checked against the accepted range in the input table below. A value outside its range stops the calculation rather than producing a misleading figure — the results blank out and a message appears.
3. The validated values are substituted into the expression above, which resolves Lifetime Release per Garment together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — First Wash, Final Wash, Decline Across the Life, First Wash as a Share of the Life, Average per Wash, Share of Garment Mass Lost, Captured by Filtration, Reaching the Environment, Captured, Annual Production and Released, Annual Production — come from the same pass, so they always describe the same case as the headline figure.
5. Results are rounded for display only. The full-precision value is used throughout the chain, so reading a rounded intermediate figure back into the tool by hand can shift the last digit.

What each input means

Where to read each value on the floor, the unit it must be in, and the range the tool accepts.

What the tool returns

The headline figure and every supporting value it is built from.

Worked example

The tool loads with this case already solved — the Lifetime Release per Garment shown above is its answer. Change one value and the difference from this baseline is the sensitivity of the result to that variable.

How to use it

1. Work through the input groups in order — Garment & Shedding and Capture & Volume. The defaults are a realistic case, so you can change one value at a time and watch what moves.
2. There is no calculate button. Every figure recalculates as you type or drag, which is what makes this usable for a what-if sweep rather than a single answer.
3. Read Lifetime Release per Garment in the dark results panel — that is the headline figure, expressed in mg.
4. Check the supporting rows underneath (First Wash, Final Wash, Decline Across the Life, First Wash as a Share of the Life, Average per Wash, Share of Garment Mass Lost, Captured by Filtration, Reaching the Environment, Captured, Annual Production and Released, Annual Production) before acting on the headline — they are where an implausible input usually shows itself first.
5. Reset to defaults returns every field to the reference case, which is the quickest way to check whether a surprising result came from the tool or from an input you had changed earlier.

Where this is used

• Process planning — establishing Lifetime Release per Garment before a trial is booked, so machine time and material in Sustainability, ETP & Utilities are committed against a calculated figure rather than an estimate.
• Costing and quotation — Lifetime Release per Garment is an input to the cost sheet, and quoting from a worked number rather than a remembered one is what keeps a margin intact.
• Troubleshooting — when the floor result drifts from plan, entering the measured values (starting with Garment Mass) shows how much of the gap in Lifetime Release per Garment each variable explains.
• Teaching and study — the accepted ranges bracket normal Sustainability, ETP & Utilities practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Assumptions and limits

• Shedding rates in the literature vary by more than an order of magnitude for nominally similar fabrics, because the test conditions dominate: machine type, load ratio, water volume, temperature, detergent, mechanical action and the filtration used to recover the fibre all move the result, and results from different protocols should not be compared. Use a rate measured under the protocol the claim will be judged by. The geometric decay is a reasonable description of the depletion of loose surface fibre and does not describe the fragmentation of the fabric itself, which continues indefinitely and rises again late in life as the structure abrades and pills - so a very long garment life will shed more in its final washes than this model allows. Mass is the honest unit here; fibre COUNT is what much of the published work reports and the two are not interchangeable, since a fine microfibre fabric releases far more fragments per milligram than a coarse one. Filtration efficiency is quoted for the fibre the filter is rated on, and the fraction reaching the environment is what passes both the machine filter and the wastewater plant - a municipal works removes a large share of what arrives, and the residue leaves in the sewage sludge rather than in the effluent, which relocates the problem rather than ending it.
• Every input is bounded to the range normal practice occupies (Garment Mass 20 to 3000 g, First-Wash Shedding Rate 5 to 3000 mg/kg and Decay per Wash 0 to 30 %, and so on for the rest). Those bounds are guard rails against typing errors, not a claim that the formula fails one unit outside them.
• The calculation is deterministic: the same inputs always give the same result. It carries no allowance for machine condition, operator skill, ambient conditions or lot-to-lot material variation unless an input above explicitly represents one.
• Nothing is sent anywhere. The maths runs in your browser, so the numbers you type never leave the page.

Questions people ask