Mercerisation Baume, NaOH Concentration & Barium Activity Number

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: Liquor Strength, Fabric Through the Range, Wet Pickup, Blank Titre, Unmercerised Control Titre and Mercerised Sample Titre.
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 Sodium Hydroxide together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Specific Gravity, Sodium Hydroxide, Caustic Carried on the Goods, Barium Activity Number, Barium Uptake vs Unmercerised and Strength vs Full-Mercerising Threshold — 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

Substituting

The 128 kg of caustic riding out of the mangle on half a tonne of cloth is the number that pays for a caustic recovery plant. It is not consumed by the reaction - almost all of it is recoverable by evaporation, and it is the single largest chemical stream in a mercerising range.

How to use it

1. Work through the input groups in order — Liquor Strength and Barium Activity (AATCC 89). 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 Sodium Hydroxide in the dark results panel — that is the headline figure, expressed in % w/w.
4. Check the supporting rows underneath (Specific Gravity, Sodium Hydroxide, Caustic Carried on the Goods, Barium Activity Number, Barium Uptake vs Unmercerised and Strength vs Full-Mercerising Threshold) 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 Sodium Hydroxide before a trial is booked, so machine time and material in Wet Processing (Dyeing & Printing) are committed against a calculated figure rather than an estimate.
• Costing and quotation — Sodium Hydroxide 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 Liquor Strength) shows how much of the gap in Sodium Hydroxide each variable explains.
• Teaching and study — the accepted ranges bracket normal Wet Processing (Dyeing & Printing) practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Reading the result

Typical bands and what each one is telling you.

Assumptions and limits

• The per cent NaOH fit is valid from 8 to 32% w/w, which is roughly 11 to 36 degrees Baume, and covers slack through full mercerising; do not extrapolate it to caustic recovery liquors or to the dilute alkali of a scouring bath. Baume readings must be temperature-corrected to the scale reference before conversion - the scale is defined at 60 F and a tank run at 20 C or higher reads low, which understates the true concentration. The barium activity number is a relative measure that depends on the unmercerised control being genuinely comparable cotton; a control of different origin, maturity or preparation history moves the denominator and with it the reported result. Barium activity also cannot distinguish tension-mercerised from slack-mercerised goods, because both convert the lattice - lustre has to be assessed separately.
• Every input is bounded to the range normal practice occupies (Liquor Strength 8 to 40 deg Be, Fabric Through the Range 1 to 20000 kg and Wet Pickup 30 to 200 %, 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.

Standards and further reading

• AATCC Test Method 89 - Mercerization in Cotton, which defines the barium activity number and the titration this tool computes it from.
• ASTM D629 - Quantitative Analysis of Textiles, for the associated compositional work.
• ISO 105-A01 - preparation of specimens, used when the mercerised goods go on to fastness testing.
• Baume scale, heavy form: SG = 145 / (145 - deg Be), the National Bureau of Standards convention at 60 F.

Questions people ask