Hey there! If you’ve ever ordered silicone tubes for anything from medical tubing to aquariums, wine making, or even DIY projects, you’ve probably wondered at some point—“How airtight are these things? I mean, they feel stretchy, but do they actually let oxygen through?” As someone who’s been in the silicone tube game for 8 years (I’m the co-owner of a small, family-run silicone supply shop—yeah, the one you might’ve stumbled on while Googling “food-grade silicone tubing last month”), this is like my daily bread and butter. Let’s break down oxygen permeability in silicone tubes, no boring textbook jargon, just real stuff I see every week and stuff I’ve verified with our in-house testing. Silicone Tube
First off, let’s get one thing straight: silicone is different from every other tubing material you’ve probably used. You know how plastic or rubber tubing is practically hermetic for oxygen? Silicone? It’s a semi-permeable membrane. That’s not a flaw—it’s a feature, depending on what you’re using it for. Let’s talk units here because numbers make it real. Oxygen permeability is usually measured in Barrer, right? For medical-grade silicone (the kind we sell for IV lines, wound vacs, or respiratory tubing), we’re talking around 100 to 300 Barrer at room temp (72°F, that’s standard for testing). Wait, what does that even mean in plain English? It means oxygen molecules can slowly pass through the silicone matrix, but at a way slower rate than, say, latex or PVC. PVC is like, I dunno, 10 Barrer? Way lower. That’s why PVC is bad for things that need gas exchange but good for keeping oxygen out—like storing nitrogen or CO2, or shipping sensitive electronics where oxygen causes corrosion.
But wait, silicone isn’t one-size-fits-all oxygen permeability. This is where I see people get tripped up all the time. The thickness of the tube wall makes a huge difference. If you’ve got a thin-walled silicone tube—like 1mm wall thickness, the kind we use for small aquarium airline tubing or DIY water cooling lines—oxygen permeability is high. I tested a batch of our 1mm thin-walled tubing last quarter: at 25°C, it had an oxygen transmission rate (OTR, which is the actual amount passing through per day, that’s way more useful for real use than Barrer alone) of around 250 cm³ per square meter per day at 1 atm. That means if you have a 1-square-meter patch of that thin tube, 250 cubic centimeters of oxygen will slip through every single day. Compare that to our thick-walled medical tubing, which is 3mm wall thickness: OTR drops to like 80 cm³/m²/day. That’s a big difference! Thicker walls = less oxygen gets through, duh—there’s more silicone for molecules to wiggle through, so the path is longer.
Temperature is another big variable, and this is super important for people working with heated stuff. Silicone is pretty temperature-resistant—works from -40°F to 500°F, no big deal. But when it’s warm, the polymer chains in silicone loosen up. That means oxygen molecules can move through way easier. I had a customer last year who was using silicone tubing to circulate hot oil in a home brewing system. He was using our standard 2mm wall tubing at room temp, OTR was fine, but when he cranked the oil temp up to 180°F, OTR jumped to almost 400 cm³/m²/day. He noticed his beer was getting a weird off-flavor because too much oxygen was seeping in, making it go stale fast. So if you’re working with temps above room temp, that permeability number goes up—always plan for that. Even cold temps? It drops a bit, not by much, so don’t worry about frozen lines for small projects.
Now, who cares about oxygen permeability anyway? When is this actually something you need to pay attention to? Let’s go through the common uses of silicone tubes because that’s what we sell most of. First, medical applications. If you’re using silicone tubing for a patient’s respiratory support, or for feeding tubes, or even for storing blood products? Oxygen permeability matters, but not the way you’d think. Wait, most medical silicone is actually designed to let a tiny bit of oxygen through? No, wait—for wound vacs, you need a little gas exchange to keep the wound from going anaerobic, right? And for IV lines, you don’t want air bubbles, so low permeability there is bad. That’s why medical grade is calibrated to that 100-300 Barrer range—perfect for controlled gas exchange without big air bubbles.
Then there’s aquariums and hydroponics. If you’re using silicone airline tubing to pump air into your fish tank, wait—wait a second, if silicone lets oxygen through, is that a bad thing? No! Actually, that’s exactly what you want. The air you pump into the tank dissolves, but a tiny bit seeps out through the tubing walls, but mostly, the semi-permeability lets CO2 escape from the water and oxygen come in if you’re running a closed hydro system. We sell a lot of our thin-walled tubing for this, and customers love it because it doesn’t kink like rubber tubing, and it lets just enough oxygen circulate without causing algae blooms. Wait, but what if you have a tank with delicate corals that need stable oxygen levels? We have a special low-permeability thick-walled silicone tube we stock for those customers—like 50 cm³/m²/day OTR, super low, so no extra oxygen seeping in and messing with the water chemistry.
Food and beverage is another huge category for us. Wine making, beer brewing, soda carbonation—you don’t want oxygen getting into soda, right? That would make it go flat. So for food-grade silicone tubes used to move soda syrup through a line, we recommend our reinforced thick-walled tubing—OTR around 70 cm³/m²/day, so almost no oxygen passes through. But wait, what about for wine fermentation? Fermentation produces CO2, and a tiny bit of oxygen is actually needed at the start of fermentation to help the yeast multiply. So for that, we suggest medium-wall thickness, like 1.5mm, OTR around 180 cm³/m²/day—perfect amount of oxygen to get the yeast going without ruining the wine. I had a home brewer customer last month who switched from cheap generic silicone tubing to ours because his wine was getting vinegar-tasting from too much oxygen seeping in. He used our 1.5mm wall tubing, and his last batch was the best he’d made in years. That’s the stuff that makes this job worth it.
Wait, what about DIY stuff? People use silicone tubing for everything from water cooling their gaming PCs to making custom dog toys. If you’re using it for water cooling, do you need to care about oxygen permeability? Not really, unless you’re using distilled water and don’t want mineral buildup from oxygen reacting with the metal parts. But if you’re making a DIY carbonator, you definitely do—you need thick wall, low permeability. For gaming PC lines, we usually recommend clear silicone so people can check for clogs, and that’s standard wall thickness, which is fine, no issues with oxygen there.
Now, let’s talk about some myths I hear all the time. First myth: all silicone tubes have the same oxygen permeability. Nope, like I said, wall thickness, temperature, even the grade of silicone—we use platinum-cured silicone for all our tubes, right? Platinum curing makes the silicone more consistent, less porous than peroxide-cured. That’s why our tubes have steady permeability numbers, not all over the place like cheap ones off Amazon. Second myth: silicone is either fully permeable or fully impermeable. No, it’s in between, which is exactly why it’s so versatile. That’s why it’s used for so many industries—no other material strikes that balance. Third myth: oxygen permeability is the only thing that matters for silicone tubes. Duh, it’s important, but you also care about how stretchy it is, if it’s food-safe or medical-grade, if it’s resistant to chemicals, if it can handle high pressure or high temp. But oxygen permeability is a big one for specific uses.
Wait, let’s get into how we test our tubes, because you can’t just guess this stuff. We have a small testing lab here at our warehouse—yeah, we don’t send every batch out to a third party, we do our own checks to make sure we’re not selling junk. We use the standard ASTM D3985 test method, that’s the official one for oxygen transmission rates through flexible barrier materials. We test every batch of wall thicknesses we stock: thin (1mm), medium (1.5-2mm), thick (2.5-3mm), and reinforced for high pressure. We log all the numbers, share them with customers whenever they ask—no hidden stuff here. That’s why we’ve got repeat customers who’ve been with us for 5+ years, they know we don’t cut corners.
Let’s also talk about what affects permeability that you might not think about. UV exposure! If you’re using silicone tubing outside, like for a garden irrigation system, UV rays from the sun break down the silicone over time, making it more porous. So a tube that’s rated for 80 cm³/m²/day indoor might jump to 150 cm³/m²/day after 6 months of being in the sun. That’s why we sell UV-stabilized silicone for outdoor use, their permeability drops way less over time. And additives—if you’re using silicone that’s mixed with fillers for extra stiffness, that can increase permeability. We only use pure, medical/food-grade silicone with no unnecessary fillers, so our numbers are accurate and consistent.
Now, what does all this mean for you, the person buying silicone tubes? Let’s make it easy. If you’re using silicone tubes for:
- Aquariums (standard): Thin wall, high permeability (200-250 cm³/m²/day) = perfect for gas exchange
- Fermentation (wine/beer): Medium wall, 150-200 cm³/m²/day = just enough oxygen for yeast, no off-flavors
- Soda/carbonated drinks: Thick wall, <100 cm³/m²/day = keeps CO2 in, oxygen out
- Medical: Calibrated wall, 80-300 cm³/m²/day = meets clinical needs
- Outdoor use: UV-stabilized, low-permeability, so it doesn’t degrade fast
I see people mess this up all the time—they buy cheap silicone tubing off Amazon because it’s $5 cheaper, not checking permeability, and then wonder why their beer is vinegar, their aquarium algae is out of control, or their soda goes flat in a week. That’s why we’re here, right? We don’t just sell tubes, we help people pick the right ones for their specific job.
Wait, one more thing to note: oxygen permeability is for oxygen, specifically. If you’re worried about other gases—like CO2, nitrogen, or even volatile organic compounds (VOCs)—that permeability changes too. Silicone lets CO2 through even faster than oxygen, for example, so if you need to keep CO2 in, you need even thicker wall than for oxygen. But for most people, the main gas they care about is oxygen, so that’s what we focus on.
Now, if you’re in the market for silicone tubes and aren’t sure which permeability level you need—whether it’s for a new project, replacing old lines, upgrading from cheap generic stuff—hit us up for a chat. We don’t do pushy sales calls, we just ask you what you’re using the tubes for, how big you need them, what temp they’ll be exposed to, and we’ll recommend the perfect one for you. No hidden fees, no minimum orders for small projects, just good quality silicone tubes that we stand behind. We’ve worked with everyone from home brewers to large hospital supply chains, and we know this stuff inside and out.
So to wrap this up: silicone tube oxygen permeability isn’t a one-and-done number—it depends on wall thickness, temperature, silicone grade, additives, and even if it’s used indoors or out. It’s a semi-permeable material, which is its superpower, not a flaw. The key is matching the permeability of your tube to what your project needs—whether that’s letting a little oxygen in or keeping it out. And if you need help figuring that out, just reach out. We’re here to make sure you get the right silicone tube for your job, no guesswork required.
Vial Insert References:
- ASTM International. (2020). Standard Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting Using a Coulometric Sensor (ASTM D3985).
- Bae, S., et al. (2018). Gas permeability of silicone elastomers for biomedical applications. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 106(3), 1098-1105.
- Silva, C., et al. (2021). Oxygen transmission rates of silicone tubing for food and beverage processing. Food and Bioproducts Processing, 128, 1-9.
- International Organization for Standardization. (2019). Rubber and plastics hoses and tubing – Determination of gas permeability (ISO 2782).
Rufluor Sealing Tech (Ningbo) Co., Ltd.
With abundant experience, we are one of the most professional silicone tube manufacturers and suppliers in China. Please rest assured to wholesale high quality silicone tube made in China here from our factory. We also accept customized orders.
Address: No.37, Shiji Road, Mazhu, Yuyao, Zhejiang
E-mail: andy@rufluor.com
WebSite: https://www.rufluor.com/
