I’ve been asked this Quick Question before, usually when a fire door inspector is on-site or when the top latches have become detached:

Is fire exit hardware required to be attached to a fire door with through-bolts?

As with most questions related to fire doors, I headed to NFPA 80 – Standard for Fire Doors and Other Opening Protectives.  There I found a couple of references to fire exit hardware in Section 6.4.4.8 – Door Attachments (refer to this section for other attachment requirements).

This paragraph says that the doors need reinforcements for fastening the hardware with machine screws, or the hardware must be attached with through-bolts:

6.4.4.8.1 – Locks, latches, surface-mounted top and bottom bolts, and fire exit hardware shall be secured to reinforcements in the doors with machine screws or attached with through-bolts.

This paragraph references wood and plastic laminate doors, and says that the hardware must be secured with through-bolts or with steel screws:

6.4.4.8.5 – Fire exit hardware and surface-mounted top and bottom bolts shall be attached to wood and plastic-covered composite doors with through-bolts or with steel screws at locations specified in the door manufacturer’s installation instructions.

BUT – I took a look at the Von Duprin 9927L-F installation instructions and I found something interesting.  For both the top and bottom latches the installation instructions show “#325 sex bolts (required)” – this is more restrictive than what is permitted by NFPA 80.  I checked with one of our compliance engineers and confirmed that because through-bolts are required by our installation instructions, they must be installed to maintain the UL listing for the fire exit hardware.

My advice is…check the manufacturer’s instructions and use the required fasteners.  If you have experience with this in the field, please share in the comments!

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