Understanding ASTM F739: Permeation Testing for Protective Clothing Materials

09 Sep 2026

A Closer Look at one of the Most Widely Used Standards for PPE

Anyone who buys, specifies, or tests protective clothing for chemical exposure eventually runs into ASTM F739. It is one of the most widely referenced standards in the personal protective equipment (PPE) world, and it answers a simple but critical question: how long can a glove, suit, or barrier fabric hold back a hazardous chemical before that chemical moves through the material at the molecular level?

This is different from a liquid simply soaking through a seam or a pinhole. Permeation is a slower, less visible process, and it is often the more dangerous one because a garment can look completely intact while chemical is passing through it.

What ASTM F739 Actually Tests

ASTM F739, titled Standard Test Method for Permeation of Liquids and Gases Through Protective Clothing Materials Under Conditions of Continuous Contact, evaluates flat specimens from finished protective clothing items or from candidate materials. That includes gloves, sleeves, aprons, suits, coveralls, hoods, and boots. The method also allows testing of seams, since seams are frequently the weak point in an otherwise resistant material.

In the test, a specimen is mounted between two chambers in a permeation cell. One side is exposed to the challenge chemical (the continuous contact condition referenced in the title). The other side is monitored, usually with a collection medium such as air or water, for the presence of the chemical as it passes through the material over time.

The Key Measurements

The standard defines several values that describe how a material performs:

• Breakthrough detection time is the point at which the chemical is first detected on the far side of the material, based on the sensitivity of the analytical method used.
• Standardized breakthrough time is the point at which the permeation rate reaches 0.1 micrograms per square centimeter per minute, which is the threshold specified in the current version of the method (F739-20).
• Normalized breakthrough time is an optional, higher threshold of 1.0 micrograms per square centimeter per minute. The standard allows reporting this figure as well, which is useful because ISO 6529, the international counterpart to F739, uses this higher threshold by convention in parts of Europe. Reporting both numbers helps when comparing US and international data.
• Permeation rate and cumulative permeation describe how much chemical moves through the material once breakthrough occurs, and whether that rate levels off at a steady state.

Longer breakthrough times, lower permeation rates, and lower cumulative permeation all indicate better barrier performance. Short breakthrough times or high permeation rates indicate the material is a poor match for that specific chemical.

Why the Distinction Between Penetration and Permeation Matters

It is worth separating F739 from a standard like ASTM F903, which tests penetration, meaning visible liquid leakage through a material, seam, or closure. Permeation is a diffusion process at the molecular level and can occur even through materials that show no visible sign of failure. A glove can pass a penetration test and still fail a permeation test against a specific solvent. This is why chemical resistance data sheets for gloves and suits typically list breakthrough times against a panel of specific chemicals rather than a single pass or fail result.

A Result is Chemical Specific

One of the most important practical points about F739 data is that it only applies to the exact chemical, concentration, and temperature tested. A glove with an excellent breakthrough time against acetone may perform poorly against a chlorinated solvent. There is no such thing as a universal chemical resistant material, which is why selection guides built from F739 data are organized by chemical, not by product line.

The standard itself also notes an important limitation: because only limited quantitative information exists about safe dermal exposure levels for most chemicals, F739 results describe barrier performance and cannot be used on their own to infer a safe duration of contact for a worker.

Where this Standard is Used

F739 testing supports product development, quality control, and compliance documentation across industries where workers handle hazardous chemicals directly or in close proximity, including chemical manufacturing, laboratories, hazmat response, agriculture, and industrial cleaning. Reporting of results is typically done in accordance with ASTM Guide F1194, which standardizes how the breakthrough time, permeation rate, and other figures are presented so that data from different laboratories can be compared on the same basis.

The Bottom Line

ASTM F739 exists because chemical exposure hazards are not always visible, and a material that looks intact can still be letting a hazardous substance through at the molecular level. For manufacturers, understanding how their material performs against the specific chemicals their end users will encounter is not a formality. It is the basis for an honest safety claim. For buyers and safety managers, the standard provides a consistent, chemical specific way to compare materials before they end up on someone's hands in the field.