If you've spent any time looking at commercial door hardware lately, you've probably run across the von duprin 3347 more than a few times. It's one of those industry staples that shows up in schools, hospitals, and office buildings because, quite frankly, it just works. While a lot of people might see a "panic bar" and think they're all the same, anyone who has to install or maintain them knows that the details matter a lot.
The 3347 isn't just your run-of-the-mill exit device. It's specifically designed for narrow stile doors—those doors with the thin frames often made of aluminum and glass that you see at the entrance of a strip mall or a modern office lobby. Because there isn't much room to mount a massive piece of hardware, you need something that can fit into a tight space without sacrificing the strength needed to handle thousands of people walking through every day.
Why the 3347 Stands Out in a Crowded Market
One of the first things you notice about the von duprin 3347 is its build quality. Von Duprin has a reputation for being the "tank" of the hardware world. When you pick up one of these devices, it feels heavy and substantial. It's not made of the flimsy, thin-gauge metals you find in budget-friendly alternatives. This is important because exit devices take a beating. Kids kick them, delivery drivers ram carts into them, and they get slammed shut hundreds of times a day.
The 3347 is a vertical rod device, which sets it apart from the "rim" devices that just latch into the side of a door frame. Instead, it uses rods that extend to the top and bottom of the door. When you push the bar, those rods retract, letting the door swing open. This design is particularly great for double doors where you don't want a permanent post (a mullion) sitting in the middle of the opening when both doors are open.
The Difference Between the 33 and 35 Series
A common point of confusion is the difference between the 33 and the 35 series. If you're looking at a von duprin 3347, you might also see references to the 3547. To be honest, they are functionally identical. The real difference is all about the look.
The 33 series has a "grooved" case—it has those little lines running along the surface of the push pad and the housing. It gives it a bit more of a classic, industrial look. The 35 series, on the other hand, is smooth. It's a bit more modern and sleek. Most architects choose between them based entirely on the aesthetic of the building, but from a security and durability standpoint, you're getting the same high-quality internal guts regardless of which one you pick.
Installation Isn't Always a Walk in the Park
I won't sugarcoat it: installing a von duprin 3347 can be a bit of a project if you've never done it before. Because it's a vertical rod device, you have to deal with timing. If the top rod retracts but the bottom one is still dragging on the floor, the door isn't going to open easily. It takes a bit of "finesse" to get everything lined up just right.
The good news is that Von Duprin designs these with maintenance in mind. Everything is adjustable. If the building settles over time and the door shifts a little, you don't necessarily have to rip the whole thing off and start over. You can usually tweak the rods to get that smooth "click" back when the door latches. It's that level of engineering that makes locksmiths and facility managers stick with this brand even if the upfront cost is a bit higher than some knock-off brands.
Dealing with Fire Ratings
Safety is the whole reason these things exist in the first place. When a fire alarm goes off or people need to get out of a building fast, the door has to open—no excuses. You'll often see the von duprin 3347 available as a "Fire Rated" (F) version.
The fire-rated version (usually called the 3347-F) is built to stay latched even under intense heat to help contain a fire, but it will still allow people to exit instantly from the inside. It's a delicate balance of engineering. If you're replacing an old device, you absolutely have to check if your door requires a fire-rated label. You can't just swap a fire-rated device for a standard one because it's cheaper; that's a massive code violation and, more importantly, a huge safety risk.
Quiet Operation and Electrified Options
One thing that has changed over the years is how much we care about noise. In a hospital or a quiet office wing, the "CLANG" of a panic bar can be pretty annoying. The von duprin 3347 has improved quite a bit in this area. They offer "quiet" versions and dampeners that help muffle the sound of the metal-on-metal contact.
Also, we're seeing a lot more "EL" or "QEL" versions of these devices. These are electrified versions that allow you to connect the door to a keycard reader or a building management system. If you want the door to stay locked until someone swipes their badge, or if you want the doors to automatically unlock during business hours, the electrified 3347 makes that possible without needing a bunch of separate magnetic locks that can look messy.
Choosing the Right Finish
It might seem like a small detail, but the finish on your von duprin 3347 matters for both durability and looks. Most people go with the classic "US28" (Satin Aluminum), which matches those narrow stile glass doors perfectly. However, if you're in a coastal area with salt air or a high-moisture environment, you might want to look into stainless steel finishes (US32D). They hold up much better against corrosion.
There are also darker finishes like "Duranodic" (dark bronze) which are popular in modern storefronts. Just keep in mind that the finish doesn't just affect the look—it also affects how well the device hides fingerprints and scratches over years of heavy use.
Maintenance Tips to Keep It Running Smoothly
If you already have a von duprin 3347 installed, a little bit of grease goes a long way. You don't need to soak it in oil, but a little bit of high-quality lubricant on the latch bolts and the pivot points of the push bar once a year can prevent that "gritty" feeling.
Also, keep an eye on the floor strike. Since the 3347 has a bottom rod, there is usually a small hole or strike plate in the floor. These are notorious for collecting dirt, rocks, and salt during the winter. If that hole fills up with gunk, the bottom rod won't seat properly, and your door might not actually be locked when you think it is. A quick vacuum or a poke with a screwdriver to clear out that debris can save you a lot of headaches.
Wrapping Things Up
At the end of the day, the von duprin 3347 is popular because it solves a specific problem really well. It fits on thin doors, it offers top-and-bottom security, and it's built to last longer than the person who installed it. It's certainly not the cheapest option on the shelf, but when you consider how many times a door gets used over a decade, it usually ends up being the most cost-effective choice in the long run.
Whether you're an architect spec'ing out a new building or a business owner tired of your front door jamming, this device is a solid, reliable workhorse. It's one of those pieces of hardware that you don't really think about when it's working perfectly—and that's exactly how it should be.