The other day I was perusing the Von Duprin 98/99 series installation instructions, because someone asked me how to change the 996L lever trim from nightlatch (storeroom) function to classroom function.  The change involves the NL drive screw (NL = nightlatch), and the question took me back to The Olden Days when I was a manufacturers rep for LCN and Von Duprin.  I had a supply of parts in the top left drawer of my desk, including a stash of NL drive screws.

Side note/funny story…last year I had dinner with a group of coworkers, and I was seated next to someone I had never met who works for our commercial technical product support department.  He told me that he started working for LCN back when he was in high school.  When I introduced myself, the light bulb of recognition flashed on and he said that when he first started working for LCN he thought “Lori Greene” was a company.  He said he was frequently sent to the manufacturing floor to get a handful of parts to send to Lori Greene.  😀

Anyway, back to the NL drive screw.  When a Von Duprin 98/99 device is shipped from the factory, the NL drive screw is installed and the device is nightlatch function, also known as storeroom function.  The outside lever is always locked.  To change the lever to classroom function – which can be left locked or unlocked using the key, the NL drive screw is removed.  If someone decides later to change the function back to storeroom/nightlatch function, the NL drive screw is usually long gone, hence the stash in my desk.

One thing to consider with regard to the nightlatch vs. classroom function is a change coming in the 2027 International Building Code (IBC) that is related to school security.  That edition of the code will require classrooms and other occupied spaces as well as exterior doors in schools to be lockable from the inside.  A traditional classroom function lockset will not comply, nor will panic hardware with a classroom function lever handle on the outside.  You can read more about this change here.

Here’s a video on how to use the NL drive screw to change the function on Von Duprin panic hardware:

If you have an idea for another “What’s that?” post, leave a comment!

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