Police tactical units rarely have a chemist on the procurement team, yet glove certification documents are full of chemistry and test jargon. This guide explains what the numbers actually mean, so buyers can separate tested protection from polished paperwork.
Who Writes the Rules
Several bodies publish documents that matter for CBRN gloves. ISO and CEN are the main sources: EN ISO 374-1 defines protective performance against chemicals and assigns Type A, B or C ratings based on how many test chemicals achieve a 30-minute breakthrough level. EN ISO 374-5 covers bacteria, fungi and viruses. The underlying test methods are ISO 6529 and its US counterpart ASTM F739, which measure chemical permeation, and ISO 13982 / ASTM F903 for penetration against dry particles and liquid splash. In the United States, NFPA 1991 and NFPA 1994 wrap these material tests into a full equipment standard. For general glove requirements such as sizing and dexterity, EN ISO 21420 applies. A supplier should be able to name, for every claim, the document number, its edition year, and the laboratory that ran the test.
Permeation, Penetration and Breakthrough in Practice
These three words describe different failure routes. Permeation is chemistry at molecular level: chemical molecules dissolve into the glove material, travel through it, and emerge on the skin side, even when the surface looks intact. Penetration is a physical leak: chemical flows through pinholes, seams, or a badly welded cuff. Breakthrough time is the stopwatch reading on permeation tests - the time until the chemical is detected on the far side at a defined detection limit.
The practical takeaway: two gloves rated for the same chemical are not equivalent if one was tested at 0.3 mm thickness and the other at 0.9 mm. Barrier performance scales with thickness and with material formulation, so the certificate must state the exact thickness tested and match the product being offered.
How to Read a Test Report
A credible report lists the chemical, the standard and its version, the sample thickness, the test temperature (typically 23 °C), and the measured breakthrough time plus the permeation rate. Watch for two traps. First, a result written as "greater than 480 minutes" is a censored observation: the test simply ended before breakthrough happened. It does not mean the glove lasts days. Second, tests are run on flat swatches cut from the palm or finger. Seams, the finger crotch area, and welded joints are usually the weakest points, so a whole-glove leak test is a meaningful supplement, not a redundancy.
Gaps in Imported Products and How to Verify
Common weaknesses in imported gloves include: claims of "meets EN 374" without the Type letter or chemical codes; test reports that name a different thickness or material batch than the delivered goods; missing bacteriophage data when EN ISO 374-5 is claimed; and no Declaration of Conformity tying the shipment to a certificate. For gloves sold as Category III PPE in the EU, the certificate must come from a Notified Body with a four-digit number.
Before signing, ask for: the Declaration of Conformity with certificate number; the full permeation report for each chemical you named in your threat assessment; written confirmation that report thickness equals delivered thickness; and batch traceability. Then check the certificate number against the Notified Body's public database. Ten minutes of document verification is the cheapest protective equipment a tactical unit will ever buy.