Breakthrough time is the moment a chemical crosses a glove film and is detected inside it, and for trichloroethylene a nitrile exam glove is often the wrong barrier. Testers report it as a detection time measured under a fixed contact, temperature and collection protocol rather than a rating printed on the box. Exam-grade nitrile is thin, single-use, and tested against micro-organisms, not against solvents.
What does a chemical breakthrough time actually measure?
In a permeation cell, the challenge chemical sits against the outside of the glove film while a collection medium on the inside is sampled at intervals. Breakthrough time is the elapsed time from first contact to the first detection of the chemical inside the glove. Four related terms get used loosely.
| Term | What it describes | What it changes in purchasing |
|---|---|---|
| Breakthrough time | Time until the chemical is detected inside the film | Compare it with task length; longer is not automatically safe |
| Permeation rate | How fast the chemical crosses once inside | One breakthrough time does not predict total exposure |
| Degradation | Swelling, softening or colour shift in the film itself | Explains gloves that tear mid-task with no breakthrough |
| Dexterity and fit | How much feel and grip force the glove takes away | Drives tear rate and change-out cost |
A glove can pass a permeation test and still degrade, and one that looks untouched after ten minutes may be permeating the whole time.
How do trichloroethylene and nitrile interact?
Nitrile butadiene rubber holds up well against many oils, greases and alcohols, which is why it dominates clinic exam and cleanup supply. Chlorinated solvents sit in a harder category. TCE is a chlorinated solvent, so it falls where nitrile resistance is usually described as limited rather than good, with permeation and degradation both in play.
For sustained contact, the materials commonly specified are laminated film, butyl rubber or fluoroelastomer, verified against the maker's chemical resistance data. A disposable nitrile exam glove is not a chemical-protective glove. Nitrile examination gloves sold in North America are specified against ASTM D6319, covering dimensions, strength and powder residue for patient care, and nothing about solvent permeation.
Which standard sets permeation testing for gloves?
ASTM F739 is the standard test method for permeation of liquids and gases through protective clothing materials under continuous contact. EN ISO 374, which replaced EN 374, is the glove-specific standard for protective gloves against dangerous chemicals; it assigns performance levels from breakthrough times measured on the finished glove. Compare supplier data only when the chemical, temperature and thickness match, and treat a missing chart entry as unsuitable.
| Claim | Standard behind it | What it does and does not establish |
|---|---|---|
| Examination grade nitrile | ASTM D6319 | Dimensions, strength and powder limits. Silent on solvents |
| Chemical protective glove with a performance marking | EN ISO 374 | Measured breakthrough performance for the chemicals in the maker's chart |
| Permeation data | ASTM F739 | Behaviour under the conditions tested |
Gloves imported for resale in Canada also carry supplier obligations, which our note on what an MDL means for nitrile gloves sold in Canada explains.
Do thicker gloves always last proportionally longer?
No, and the arithmetic is not linear. Permeation is a diffusion process, so thickness influences breakthrough time through a squared relationship rather than a proportional one, and the chemical, the temperature and small film defects all shift the result. One mil is 0.0254 mm, so a 6 mil glove runs about 0.15 mm of film, and that extra film shows up as grip fatigue on a long cleanup shift. Our guide to nitrile glove thickness in mils walks through the conversions.
How should a clinic choose gloves for solvent tasks?
Start with the chemical, not the glove. A safety data sheet identifies the substance and its exposure controls, and in Ontario WHMIS 2015 requires a supplier label and a safety data sheet in the workplace for hazardous products.
- Name the chemical from the SDS and note the task temperature.
- Check the maker's chart for that chemical, model and thickness. No entry means unsuitable.
- Compare breakthrough time with contact duration and keep a margin.
- Step up the material class for chlorinated solvents and ketones.
- Match the glove to the wearer. Our breakdown of type I and type IV glove reactions covers the skin side.
Most clinics end up holding two nitrile lines: a lighter exam glove for patient care, and a heavier film glove for cleanup work. A 6 mil heavy-duty black nitrile glove covers the cleanup side, and a wholesale case of touch-flex nitrile gloves keeps the exam side stocked at case pricing. Sites that also run sterilizers often review monitoring volume in the same pass, and the five-pack biological indicator trial at $12.99 with shipping included is a practical way to check that cadence. The CliniEco learning hub collects the explainers behind these decisions.
Ordering for a clinic, lab or care home? Wholesale and multi-site ordering covers case pricing and account setup, and the B2B wholesale collection lists the lines stocked for institutional buyers.
Related reading
- Nitrile glove thickness in mils
- What an MDL means for nitrile gloves sold in Canada
- CliniEco learning hub
Frequently Asked Questions
Can I use exam-grade nitrile gloves for trichloroethylene?
Not for sustained contact. Exam-grade nitrile is specified against ASTM D6319, which covers dimensions, strength and powder residue rather than solvent permeation. For trichloroethylene, use a chemical-protective glove whose maker publishes permeation data for that solvent.
Does a higher mil thickness mean a longer breakthrough time?
Not proportionally. Thickness affects breakthrough time through a non-linear diffusion relationship, and the chemical, the temperature and film defects all move the result.
Is EN 374 the same as EN ISO 374?
EN ISO 374 is the current designation; EN 374 was the earlier European number, and the glove standard now carries the ISO prefix.
Where do I find chemical resistance data for a specific glove?
From the glove maker, not the box. Request the permeation chart for the exact model and thickness, then match it to the substance on the safety data sheet.
CliniEco Medical is a licensed medical device establishment (MDEL #35334).
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