Key Takeaway
Breakthrough time is only one part of chemical suit performance. Real protection depends on understanding the full permeation process, including steady-state flow and cumulative exposure, under real-world conditions, not just lab tests.
What does breakthrough time actually measure in a chemical suit?
Breakthrough time is the moment a lab test detects a chemical starting to move through the suit material at a defined rate. But that doesn’t mean the material was airtight until that point. In fact, low-level chemical permeation can begin well before the breakthrough clock starts ticking.
Most safety professionals see breakthrough time on a datasheet and assume it’s the full story. But that number reflects just one phase of a longer process. To really understand what breakthrough time misses, let’s look at how chemical permeation actually happens inside a suit.
What are the three stages of chemical permeation through PPE?
- Initial Penetration: Molecules start moving through the fabric before breakthrough is detected, but at levels below the 0.1 µg/cm²/min threshold.
- Breakthrough and Steady-State: Once breakthrough is recorded, the chemical begins to flow through the fabric at a relatively stable rate. This is the number you see on PPE spec sheets.
- Saturation: Over time, more of the chemical accumulates inside the suit. The longer the exposure, the more permeation builds up, especially in warm or humid conditions.
Kyle Kerbow, a chemical PPE specialist at Lakeland, explains it clearly: “There is actually chemical breakthrough before the ASTM F739 test records a breakthrough. You’re getting some permeant in there before it actually tells you that you’re getting permeation.”
NIOSH agrees. Their guide states that “all chemicals will eventually permeate protective clothing,” and that both material thickness and temperature play a major role in how quickly that happens. These stages don’t just happen in theory, they happen faster and more aggressively in the kinds of conditions workers actually face.
Why does lab-tested breakthrough time fail in real-world conditions?
ASTM F739 permeation tests happen in a lab at 23 to 27 °C and 40% humidity. But that doesn’t reflect real work conditions. Field workers face far more extreme environments.
“In Houston, we’ve got end users working inside railcars,” says Kyle Kerbow. “It can hit 130 degrees Fahrenheit in there. Chemicals permeate quicker at higher temperatures.”
OSHA backs that up, noting that “an increase in temperature generally increases the permeation rate of contaminants.” Research supports this too, showing that a 10 to 20 °C rise in temperature can cut chemical breakthrough time in half or more.
And heat isn’t the only factor. Real-world movement, like kneeling or leaning, plus contact with high-concentration liquids or pressurized spray, can also accelerate permeation. When real-world risks push beyond the limits of lab tests, safety pros need better tools to make accurate decisions.
What is safe use time, and why is it better than breakthrough time?
Breakthrough time only tells part of the story. To better predict how long a suit actually protects a worker, safety pros need more realistic data. That’s where safe use time come in. It’s a key indicator recognized by NIOSH and offers a more accurate view of a garment’s real-world limits.
Kyle Kerbow points to Lakeland’s PermaSURE Modeler as a practical solution to find those limits:
“You can put in your exact work temperature and it tells you how long you can wear that suit safely before it becomes dangerous.”
Unlike static lab charts, Permasure adapts to real-world variables like temperature and chemical volatility. It gives safety managers a dynamic estimate of safe wear time before workers even suit up. However, even with the right safety model, design flaws can still expose workers, so let’s take a closer look at suit construction.
How do design features impact chemical suit performance in the field?
Even suits made with similar chemical barrier films can behave very differently on the job. Small design choices can have a big impact when heat, pressure, and real-world hazards come into play.
Details like hood construction, zipper design, and glove or boot interfaces can make or break the suit’s
performance. For example:
- A poorly designed hood may not seal to a respirator, leaving the neck exposed.
- A zipper without a storm flap can become a direct entry point for chemicals.
- An open boot style can act like a funnel, letting liquid pool inside unless it’s properly sealed.
That’s why garment design matters just as much as material selection. Lakeland’s ChemMax line addresses these issues head-on, offering features like push-fit glove interfaces and flap-over boot covers. These aren’t extras, they’re essentials when workers face real chemical exposure, not just a controlled lab test.
With so many variables in play, asking smarter questions up front can help safety managers avoid costly assumptions down the line.
What questions should safety managers ask before selecting a suit?
Don’t shop based only on breakthrough time. Ask:
- What’s the temperature of your worksite?
- How long is the contact exposure?
- Is movement or pressure increasing the risk?
- Can you model safe wear time instead of guessing?
Also look at suit features:
- Hood style (standard vs respirator-fit)
- Zipper protection (flaps vs exposed)
- Glove interface (taped vs sealed system)
- Boot design (sock or boot cover?)
Kerbow puts it simply:
“They need to look at fit and function, not just the numbers. Because those numbers don’t always hold up when you’re in the field.”
Now that you know what to ask, let’s talk about a company that’s already building suits, and tools, around those exact questions.
How is Lakeland’s ChemMax line different from other chemical suits?
Breakthrough time looks good on a datasheet, but chemicals don’t care about lab conditions. In the field, heat, pressure, movement, and exposure time all speed up permeation. That means the suit that passed in a lab at 25 °C might not hold up in a railcar at 130 °F.
And if you’re making safety decisions based only on that lab number, you’re flying blind.
That’s where Lakeland stands apart. The ChemMax line gives you the protection you expect, and PermaSURE gives you the clarity you need. It calculates how long your suit will really last, based on the actual chemical, temperature, and exposure time you’re working with.
If you’re serious about safety, stop guessing. Start knowing. Explore ChemMax today.
FAQ
How does Permasure calculate safe wear time for chemical suits?
Permasure uses the chemical type, fabric, ambient temperature, and exposure duration to estimate how long a suit remains protective in real-world conditions.
Why is ASTM F739 not enough to choose chemical PPE?
ASTM F739 only measures breakthrough under fixed lab conditions. It doesn’t account for real-world work conditions that can shorten safe use time in the field.
What risks are missed by relying only on breakthrough time?
Breakthrough time ignores early-stage permeation and cumulative chemical exposure. It can give a false sense of security if used alone to select PPE.
Do all barrier films perform the same in extreme heat?
No. Even similar materials can react differently when exposed to high temperatures. Small differences in suit design and film combinations affect real-world holdout.
What should safety managers consider beyond data sheets?
They should assess actual working conditions, suit design features, and use modeling tools like Permasure to predict performance under field-specific risks.
