Permeation Test From the EN ISO 6529 report

Normalised Breakthrough Time min

Time until the permeation rate reached 1.0 µg/cm²/min for the chemical in question. A database entry of "immediate" means under 10 minutes: enter 0.

Steady-State Permeation Rate µg/cm²/min

The plateau rate from the permeation curve in the full report. If only a breakthrough time is listed, enter 1.0 for the lowest the rate can be after breakthrough.

Report Uses the ASTM F739 Criterion 1 = yes

ASTM F739 records breakthrough at 0.1 µg/cm²/min, ten times lower than the EN criterion, so its times are not EN classes. Enter 1 and the class is withheld.

Wear The task

Planned Wear Time min

Area in Contact with the Chemical cm²

The splash zone, not the whole garment: a forearm and glove cuff is a few hundred square centimetres.

Acceptable Cumulative Dose mg

From the chemical's toxicology, set by the safety adviser. The tool has no figure of its own.

EN 14325 Permeation Class

— class

1 to 6; 0 = below Class 1, or an ASTM F739 result the scale does not apply to

Class & Wear

Minutes Short of the Next Class: — min
EN Class Scale Applies: — 1 = yes
Wear Time Runs Past Breakthrough: — 1 = yes
Minutes Worn After Breakthrough: — min
Estimated Mass Permeated over the Wear Time: — mg
Share of the Acceptable Dose: — %
Minutes until the Acceptable Dose: — min
Mass per Hour over the Contact Area: — mg/h

Classes per EN 14325 clause 4.11 as printed in Lakeland's chemical permeation database: a class is met when the normalised breakthrough time is more than 10, 30, 60, 120, 240 or 480 minutes for classes 1 to 6; under 10 minutes a database lists "immediate". Normalised breakthrough is the moment the permeation rate reaches 1.0 µg/cm²/min, not the first molecule through: the chemical has been permeating at a rising rate before it, which is why the database carries the standard's warning that it can be dangerous to base safe wear time on the breakthrough time alone. ASTM F739 records breakthrough at 0.1 µg/cm²/min; EN ISO 6529 offers both rates, and the 1.0 figure is the one used for EN classes, so an ASTM time cannot be classed here. The cumulative estimate applies the steady-state rate to every minute after breakthrough and ignores permeation before it; the real curve climbs to the plateau rather than jumping, so the figure is a planning estimate, high in the first minutes after breakthrough and low if the rate is still rising. **Class, dose limit and wear time are the safety adviser's decision; this is a reading aid for the test report.**

Chemical Protective Clothing Permeation Class (EN 14325) & Cumulative Permeation Estimate — free, with the formula and a worked example, at Textile School.