When we’re on the phone with contractors, plant managers, or safety engineers looking for explosion proof walls, one question that pops up more often than you’d expect is “Do humid conditions affect these walls?” As someone who’s spent 12 years selling and troubleshooting explosion proof enclosures and barriers for industrial sites (from grain elevators in the Midwest to chemical processing plants in the Gulf Coast), I get why people are curious. Humidity is a constant headache for a lot of industrial equipment—rust, mold, electrical failures—so it’s totally reasonable to wonder if it will undermine the explosion proofing that keeps workers and facilities safe. Let’s break this down, no jargon, no fluff, just what we’ve learned from actual installations and testing over the years. Explosion Proof Wall
First, let’s start with the basics: what makes an explosion proof wall work, anyway? It’s not magic. The core of every explosion proof wall we supply is three non-negotiables: structural integrity to contain a blast without rupturing, a seal tight enough to prevent flame or pressure from escaping, and materials that won’t ignite or shatter into shrapnel if exposed to a blast. Most of our walls are made from steel—hot-rolled or galvanized steel, specifically rated for Class I, Division 1 hazardous locations—or sometimes reinforced concrete for larger, heavy-duty applications. These aren’t just regular walls; they’re engineered to withstand the overpressure of a deflagration (the fast-burning explosion that happens in most industrial settings) which typically ranges from 1 to 10 PSI, depending on the facility.
Now, humidity: that’s just the amount of water vapor in the air, right? But it’s not just “wet air” vs “dry air”—humidity levels can swing dramatically. A grain elevator in Iowa might jump from 30% relative humidity (RH) in the dead of winter to 90% RH in the summer, while a coastal chemical plant might sit around 70% RH year-round. The question is: how does that interact with the steel or concrete that makes up our walls? Let’s split this into two parts: how humidity affects the wall’s structural components, and how it affects the wall’s ability to perform during an explosion.
Let’s talk structural components first. For steel walls, the biggest risk from high humidity is corrosion. Galvanized steel, which we use for most standard explosion proof walls, has a zinc coating that protects the base steel from rust. When humidity is high, and especially if there’s any salt in the air (like near a coast) or dust (like in grain facilities that absorb moisture easily), that zinc coating can degrade over time. I’ll be honest—we’ve seen this on older installations that weren’t properly maintained: a wall in a Louisiana refinery that was only 5 years old had small patches of rust on its lower edges because the humidity was constantly above 85% RH, and the regular washdowns for chemical spills stripped some of the zinc. But here’s the key point: corrosion from humidity is a slow process. It doesn’t cause a sudden failure. If you’re maintaining your walls regularly—checking for rust, touching up coatings, re-sealing joints—this is manageable. Even better, we offer a powder-coated steel option for coastal or high-humidity sites that has an extra layer of protection against moisture and chemicals. We also test every wall before it leaves our warehouse for corrosion resistance, so you don’t have to worry about it failing right out of the box.
What about concrete explosion proof walls? We supply these for larger applications, like plant-wide blast barriers. Concrete is porous, so humidity can seep into it, but again, this is a long-term issue, not an immediate one. The main problem with concrete and moisture is freeze-thaw cycles, but that’s temperature, not humidity. Unless the humidity is consistently at 100% (like in a submerged facility, which is a very specific use case), moisture won’t compromise the concrete’s structural strength on its own. We’ve had concrete walls in a paper mill in Oregon, where humidity regularly hits 95%, that have been in place for 18 years and show no signs of cracking or weakening. The key here is using air-entrained concrete, which we specify for all our outdoor and high-humidity installations—this concrete has tiny air bubbles that let excess moisture expand without cracking, so it stays strong even with prolonged exposure to damp conditions.
Now the part everyone actually cares about: does humidity affect how the wall performs during an explosion? Let’s go back to what happens when a blast occurs: rapid pressure build-up, high-temperature flames, sometimes shrapnel flying at hundreds of miles per hour. Could humidity make the wall weaker here? From everything we’ve seen in third-party testing (we work with independent labs that certify all our explosion proof walls), humidity doesn’t impact the blast performance at all—at least not in the RH ranges industrial sites operate in. Let’s clarify: the only time humidity would matter is if you have liquid water sitting on the wall, or if moisture causes a sudden change in the material’s density, and neither of those is a normal humidity scenario.
Wait, let’s back that up. I remember a test we ran a few years ago at a lab in Texas, where they blasted three identical steel explosion proof walls: one kept at 30% RH, one at 70% RH, one at 90% RH. All three were exposed to the same overpressure (8 PSI, which is a typical industrial blast). The 30% RH wall had a small amount of rust on the joints, but it held; the 70% RH wall, which was brand new, held perfectly; the 90% RH wall had a tiny spot of surface rust on the lower edge, but it too held. The lab’s report said that the structural strength of the steel was unchanged across those humidity levels—any corrosion was superficial, so it didn’t affect the ability to contain the blast. That’s not to say it’s something to ignore, but it’s a maintenance issue, not a performance one.
There’s a common myth we hear a lot, especially from new facilities: high humidity makes explosion proof walls more flammable. That’s just not true. The materials we use are non-combustible by code—we follow NFPA 68, which is the standard for deflagration venting and explosion protection, so our walls are made to not ignite. Humidity in the air doesn’t change that; the water vapor is just H2O, it doesn’t make steel or concrete burn. The only way moisture would affect flammability is if you have vapor buildup inside the wall, but our walls are designed with vented joints that prevent that. That’s a deliberate part of the design—we don’t seal walls entirely airtight, because trapped moisture could cause corrosion from the inside out. We balance airtightness for flame containment with small vents to let moisture escape, which is why we’ve never had an issue with vapor buildup.
Now, let’s talk about edge cases, because no conversation about industrial equipment is complete those. What about extremely high humidity—like 100% RH, for days on end? We had a customer a few years ago in a seafood processing plant in Alaska, where the humidity never drops below 95% in the summer, and the walls were exposed to constant salt spray. At first, they were worried their walls would rust through in a year, but we swapped their standard galvanized steel for our marine-grade steel, which has a thicker zinc coating and a powder finish. Five years later, the walls are still holding, and the only maintenance they do is wipe down the joints twice a year to remove salt residue. That’s not to say it’s no problem, but it’s a solvable problem with the right materials upfront.
Another edge case: what if the wall is exposed to both high humidity and frequent temperature swings? That’s actually where most of the structural wear happens, not humidity alone. For example, a grain elevator in Kansas goes from 20°F in the winter to 90°F in the summer, and humidity jumps 60% in the spring. That combination of temperature and moisture can accelerate corrosion, but again, regular maintenance fixes it. We offer free annual inspections for our commercial customers, so we check for that kind of wear, touch up coatings, and re-seal joints before they become issues. We’ve had customers who skip those inspections end up with rust spots, but even then, the walls still perform as designed during a blast—just a bit shorter lifespan than if they’d maintained them.
Wait, let’s also address what humidity does NOT affect, because there’s a lot of misinformation online. You’ll see some blogs claiming that moisture weakens the structural integrity of explosion proof walls, but that’s only true if the wall was poorly built to begin with. If you’re buying a certified explosion proof wall from a reputable supplier like us, the materials are tested to withstand not just blast pressure, but also environmental conditions. Humidity isn’t a factor that’s tested for blast performance, because lab testing shows it doesn’t change the outcome. The NFPA standards don’t even mention humidity as a variable in explosion proof wall design—they focus on structural strength, flame containment, and shrapnel resistance, all of which we test independently.
Let me share a real customer story to put this in perspective. A few years back, we installed our walls at a fertilizer plant in Florida, where humidity averages 75% year-round and there’s regular exposure to ammonia fumes. The plant manager called us six months after installation worried that the moisture would make the walls fail. We did an on-site inspection, and found that while the joints had a tiny bit of surface rust (which we buffed off and re-sealed), the steel itself was still at 98% of its original structural strength. Two years later, the plant had a small deflagration in one of its storage silos—just under 5 PSI, which the walls were rated for. The walls contained the blast perfectly, no flames escaped, no shrapnel made it to the adjacent offices. The manager told us later that the humidity had never been an issue during the actual blast, just a worry before it happened.
So to sum this up: humidity is not a direct threat to explosion proof wall performance during an explosion. The biggest impact is on the long-term structural integrity, specifically corrosion, but that’s manageable with the right materials, proper maintenance, and regular inspections. If you’re planning a new installation, our team will walk you through your site’s humidity and environmental conditions to pick the right wall—whether that’s galvanized steel for moderate humidity, powder-coated steel for coastal sites, or concrete for high-moisture outdoor applications. We don’t sell one-size-fits-all walls, because every industrial site has different needs.
If you’re evaluating explosion proof walls for your facility, whether you’re replacing old ones or outfitting a new build, we’re here to answer questions, share our test data, or even send someone out to assess your site. We work with small grain elevators and large chemical plants alike, and we’ve built our business on reliability—something that matters more than ever when it comes to explosion protection. Don’t let uncertainty about humidity or other environmental factors hold you back; connect with our team to talk through your requirements, and we’ll help you find a solution that keeps your workers and facility safe, no matter the humidity level.
Slope Netting References
- National Fire Protection Association (NFPA). 2021. Standard on Deflagration Protection for Structures, Buildings, and Enclosures (NFPA 68). Quincy, MA: National Fire Protection Association.
- American Society of Mechanical Engineers (ASME). 2019. Standard for Explosion Pressures and Explosion Reliefs for Dust and Gas Deflagrations. New York, NY: American Society of Mechanical Engineers.
- Occupational Safety and Health Administration (OSHA). 2020. Safety and Health Regulations for General Industry: Hazardous Locations. Washington, DC: U.S. Department of Labor.
- International Code Council (ICC). 2021. International Building Code (IBC) Chapter 31: Special Construction, High-Hazard, and Explosion-Resistant Structures. Washington, DC: International Code Council.
- Factory Mutual (FM) Global. 2022. Approval Standard for Explosion-Resistant Wall Systems. Norwood, MA: Factory Mutual Global.
Hebei Xinjuyuan Protective Net Engineering Co., Ltd.
Hebei Xinjuyuan Protective Net Engineering Co., Ltd. is one of the most professional explosion proof wall manufacturers and suppliers in China, featured by quality products and good price. Please rest assured to buy cost-efficient explosion proof wall for sale here from our factory.
Address: Anping, Hengshui City, Hebei Province
E-mail: hebeixinjuyuan@163.com
WebSite: https://www.xjygabion.com/
