Installing a Von Duprin 304L Floor Strike Tyler J. Thomas, CRL, provides step-by-step instructions that go well beyond those he had on this otherwise straightforward job. should occupy that hole is Von Duprin’s 304L strike, known hereaſter as the 304L. The 304L can be used in conjunction with Von Duprin’s 98/99, 55, 33A/35A, and 22 Series exit devices equipped with vertical rods. It can even be found on the 287 device. This particular building on campus had a few strikes missing. I placed an order for a few 304L strikes and was ready to proceed once they arrived. Before I could install them, I needed to read what Von Duprin had to say about their installation. I figured Von Duprin had detailed in- F structions on the correct way to install the 304L. While they do have instructions on their website, they leave much to be desired. In fact, the instructions are as follows: “Grout strike into floor.” That’s it. I’ve researched and found a few other items that help. The cutout in the floor should be ⅞ inch deep and 1⅝ inches square, for example. On fresh installations, it’s recommended that you start with ¼" holes in the corner to start your cutout. I was leſt with more questions than answers, and I quickly learned that it was on me to figure out the finer details of the installation. 28 KEYNOTES DECEMBER 2014 igure 1 shows an image I think we’re all familiar with: a missing floor strike for a Von Duprin vertical rod exit device. The hardware that Installation by Deduction Von Duprin calls for using grout when in- stalling the 304L. They don’t specify beyond that. Rather than rousing the ire of my fel- low locksmiths, I’m going to invite you to use your own experience and research to determine what’s best for you. I used a non- shrink grout made by Quikrete (Figure 2). Depending on your mixing consistency, you can typically expect between 6,500 and 8,000 psi compressive strength when fully cured. I consider that sufficient. You’ll notice that the bottom of the 304L is opened. Why? I think a reasonable specu- lation is that by not closing off the bottom, you create more surface area for the grout to adhere to (five sides versus nine), and the strike can position itself fully within the grout — but more on this in a bit. Two sides of the strike have notches removed and, if I’m interpreting Von Duprin’s installation drawings correctly, those sides can be flared outward to provide a snug, dry fit before the grout. It stands to reason that using grout in the middle of the strike won’t hurt things one bit, but how much? I’ll use the bottom latch kit (part no. 050401) used on 98/99, 33A/35A, and 22 Series exit devices to figure this out. The templates for the bottom latch case mounting bracket (part no. 050546) calls for a distance between the center of the bottom mounting screw hole and the finished floor to be 111 /16 inches. Imagine you can take the door down with the bracket and latch installed. If you did, you’d find that the distance between the center of the bottom mounting screw hole and the tip of the latch is 113 /16 inches. Comparing those two measurements, you see only a difference of ⅛ inch extending into the finished floor. That doesn’t sound right; we’ve all seen the latches extend much further. What gives? The difference is made up with the 304L itself. As seen in Figure 3, the 304L actually extends 3 /16 /16 inch (3 /16 inch above the finished floor. Combining the two numbers, we get 5 /16 inch + ⅛ inch). In other words, your grout should never be applied so high that less 5 inch exists between it and the top edge of the 304L. It’s obviously advisable to go a bit beyond this to compen- sate for door sag and the hole filling with debris. For reference, the distance between the top and bottom edge of the 304L is 1 inch exactly. With these reasonable deductions, we have a good idea of what to use and the right way to use it. Aſter cleaning the exist- ing hole out, it’s time to perform a dry fit. Remember, Von Duprin recommends the cutout should be ⅞ inch deep and 1⅝ inch square. Don’t assume that the person be- WWW.ALOA.ORG
