Hey there, if you’ve ever been deep in the weeds of managing a cleanroom—whether that’s for pharmaceutical manufacturing, semiconductor fabs, medical device assembly, or even biotech research—you’ve probably stared at a structural sealant spec sheet and wondered, “Wait, can I actually use this stuff here?” Because let’s be real: cleanrooms are not your average construction site. One wrong sealant choice could mean particle contamination, outgassing ruining sensitive equipment, or worse, downtime that costs you a fortune. As a structural sealant supplier who’s been chatting with cleanroom managers, facility engineers, and QA folks for over a decade, this is one of the most common, and most important, questions we get. Today, I’m gonna break this down like we’re grabbing a coffee (no stuffy jargon, promise) and get to the real answer: yes, but only if you pick the right structural sealant—and use it the right way. Structural Sealant
First, let’s ground this in what a structural sealant actually does, because a lot of people mix them up with regular old caulk. Structural sealants are meant to bear load—think holding two building materials (metal framing, glass panels, composite panels) together so they don’t shift, crack, or come loose over time. Regular silicone caulk? It’s just for gaps, not for structural support. Now, cleanrooms have super strict rules about what materials can even live inside them. The main standards here are from organizations like ISO (ISO 14644, which classifies cleanroom particle levels), USP <795>/<797> for pharma, SEMI standards for semiconductors, and maybe ASTM E595 for outgassing. The big no-nos for cleanroom materials are: shedding particles, releasing volatile organic compounds (VOCs) or total volatile organic compounds (TVOCs) that contaminate products or equipment, and growing mold or mildew.
So let’s get to the core question: can structural sealants check all these boxes? The short answer is, the right ones absolutely can. But not every structural sealant is made for this. Most structural sealants used in construction (like for storefronts or curtain walls) are not designed for cleanrooms. They might offgas a ton when they cure, or shed tiny bits of silicone or polymer dust when they flex. But there’s a whole subset of structural sealants formulated specifically for controlled environments like cleanrooms. Let’s talk about what makes a structural sealant cleanroom-compatible.
First, outgassing testing is non-negotiable. The gold standard here is ASTM E595, which measures total mass loss (TML) and collected volatile condensable materials (CVCM). For cleanrooms, you want TML less than 1% and CVCM less than 0.1%—that means almost no stuff evaporates off the sealant, so it doesn’t leave a residue on wafers, drug vials, or microscope lenses. Some of our structural sealants for cleanrooms actually hit TML <0.5% and CVCM <0.05%, which is way below the threshold. That’s huge because even a tiny amount of condensate can ruin a $10k semiconductor wafer or a batch of cell therapy drugs.
Next, particle shedding. Cleanrooms are classified by how many particles (0.5 microns and larger) are in a cubic meter of air—Class 100 (ISO 5) is 100 particles max, down to Class 1 (ISO 1) for super sensitive spaces. Structural sealants that work here can’t shed particles when they’re cured, or when they expand/contract with temperature changes. We test our sealants for particle release using laser particle counters, the same tools cleanrooms use to monitor air quality. Our latest structural silicone for Class 100 cleanrooms doesn’t shed a single particle after full cure—we’ve run the tests ourselves, and that’s not something all structural sealants can claim. Also, we make sure they don’t have any fillers that could flake off—no chalky additives, just pure, uniform polymer.
Wait, but what about curing time? That’s a big pain point for cleanroom teams. If you have to stop production for a week while a sealant cures, that’s lost revenue. A lot of standard structural sealants take days to fully cure, and during that time, they might offgas more or shed particles. Our cleanroom structural sealants are formulated to cure fully in 24-48 hours, and we even have UV-cured options that set in minutes—game changer for small repairs or retrofits where you can’t be down long. I recently worked with a biotech company that had a leak in their Class 10k (ISO 7) cleanroom; their contractor tried a standard structural sealant, it offgassed for 5 days, made their cell culture media test positive for contamination, and shut them down for 2 weeks. Switched to our UV-cured structural sealant, cured in 15 minutes, no offgassing, no particle shedding, and they were back up and running that same day. That’s the difference between a sealant that’s just structural, and one that works for cleanrooms.
Another thing: compatibility with other materials in the cleanroom. Cleanrooms have all kinds of surfaces: stainless steel, aluminum, glass, epoxy flooring, even certain plastics. A structural sealant that works on glass might not stick to a composite panel, or might react with an epoxy floor and start offgassing. We test every one of our cleanroom structural sealants for compatibility with common cleanroom materials, and we provide a full compatibility guide so engineers don’t have to guess. That same biotech client I mentioned earlier also had epoxy flooring, and the standard structural sealant they tried started bubbling when it touched the floor epoxy—we checked, and it was a bad bond between the two, so we recommended a primer that works with both our sealant and their epoxy, and that fixed the issue.
But wait, let’s get real—there are caveats. Structural sealants aren’t a one-size-fits-all, and you can’t just use any structural sealant in a cleanroom without doing your homework. First, you have to make sure it’s actually certified for cleanroom use. A lot of sealant companies will say “it’s low-VOC” but that doesn’t mean it’s ASTM E595 certified, or that it passes particle shedding tests. We have our cleanroom structural sealants certified by SEMI for semiconductor use, and USP Class VI for pharma, so clients can trust that they meet the strictest standards. Second, application matters a lot. If you apply a structural sealant in a non-cleanroom space, and then bring it into the cleanroom before it’s fully cured, you’re bringing all the dust and particles from your shop into the controlled environment. We always recommend applying the sealant in a cleanroom annex, or prepping the surfaces inside the cleanroom, then bringing only the cured (or mostly cured) sealant in. Also, you have to follow the cure time—don’t rush it, because even a cleanroom-formulated structural sealant might offgas a bit if it’s not fully cured.
Another caveat: if your cleanroom is for something extra sensitive, like space components (ASTM E595 is required for NASA, right?) or high-volume semiconductor manufacturing, you might need to go with a specific type of structural sealant. We have a structural polyurea sealant that’s perfect for that—more flexible than silicone, so it can handle the temperature swings in semiconductor fab bays, and it’s even lower in outgassing than our standard silicone. A semiconductor fab in Arizona was dealing with structural movement in their cleanroom wall panels; they used a regular structural silicone that would crack every 6 months because of the extreme temp changes. Switched to our structural polyurea, and it’s been holding strong for 3 years, no cracks, no particle shedding, no contamination issues. That’s the kind of solution you can only get if you pick a structural sealant tailored to your cleanroom’s specific needs.
Let’s also talk about maintenance. Cleanrooms need regular inspections to make sure all seals are intact, because a broken seal can let in particles or contamination. Structural sealants for cleanrooms are designed to be easy to clean—they don’t harbor bacteria, mold, or dust, and you can wipe them down with the same cleaning solutions you use for the rest of the cleanroom. We have clients that use our structural sealants in their cleanroom ceiling and wall panels, and they just wipe them down during their regular cleaning cycles, no special treatment needed. Compare that to some generic structural sealants that get porous over time, trap dirt, and can’t be properly cleaned—big no-no for cleanrooms.
I know a lot of cleanroom managers are wary of switching from their current sealants, especially if they’ve had bad experiences in the past. But let’s put it this way: using the wrong sealant in a cleanroom is way more expensive than using the right one. The cost of downtime, product loss, revalidating your cleanroom, or even ruining a batch of drugs or semiconductor wafers is astronomical. We’ve had clients tell us that using our cleanroom structural sealants saved them over $100k in one year alone, just from avoiding contamination-related downtime and product loss. That’s why so many of the big pharma companies and top semiconductor fabs in the US and Europe use our structural sealants for their cleanroom projects.
So, to circle back to the original question: yes, structural sealants can absolutely be used in cleanroom environments. But the key is choosing the right structural sealant—one that’s tested for low outgassing, low particle shedding, compatible with your cleanroom’s materials and certification standards, and formulated to handle the structural loads your application needs. It’s not just about “is it structural” or “is it cleanroom-friendly”—it’s about the overlap between the two. A lot of suppliers cut corners on cleanroom-specific testing to make a “structural” claim, but we don’t do that. Every one of our cleanroom structural sealants goes through third-party testing to make sure it meets ISO, SEMI, USP, and ASTM standards, so our clients don’t have to do the legwork.
If you’re dealing with a cleanroom project, or you’re having issues with seals failing, contamination, or downtime related to your current sealants, don’t guess. Structural sealants for cleanrooms are a specific product category, and getting the right one can make or break your operation. We work with facility teams, engineers, and QA specialists to find the perfect sealant for their specific cleanroom class, application, and industry. Whether you’re building a new cleanroom, retrofitting an existing one, or just need to fix a seal that’s causing contamination issues, we can help.
Don’t waste another day with sealants that don’t belong in your controlled environment. Reach out to our team to talk through your cleanroom needs, get product specs, or even arrange for testing on your specific application. We’re here to help you keep your cleanroom running smoothly, without the contamination headaches.
Stainless Steel Sealant References:
ISO 14644-1, Cleanrooms and associated controlled environments — Part 1: Classification of air cleanliness by particle concentration
ASTM E595, Standard Test Method for Total Mass Loss and Collected Volatile Condensable Materials from Outgassing in Space Environments
SEMI F1, Specification for Materials for Semiconductor Processing Equipment
USP <797>, Pharmaceutical Compounding—Sterile Preparations
Taizhou Qingkai Adhesive Co., Ltd.
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