This post was published in Doors & Hardware

I frequently receive questions about alterations of existing fire door assemblies, including preparations for new hardware and filling holes left by hardware that has been removed.  NFPA 80 – Standard for Fire Doors and Other Opening Protectives addresses two types of alterations made in the field – job site preparations and field modifications.  Information was added to the 2016 edition of NFPA 80 that was not included in previous editions of the standard; those changes are noted below.

Job Site Preparations

Hardware preparations made on the job site are covered under Section 4.1.3 – Appurtenances.  The term “appurtenance” is not defined in NFPA 80, but it is generally used to describe subcomponents of an assembly.  In the case of a fire door assembly, appurtenances include locks and latches (including electrified hardware), hinges, closers, astragals, and other hardware, as well as glass lights, louvers, plant-ons, and laminated overlays.

Preparations for appurtenances must be performed in accordance with the manufacturer’s inspection procedure and under label service – typically at the manufacturer’s facility or an authorized shop where labels may be applied.  In addition, limited preparations may be made on the job site.  This section of NFPA 80 limits job site preparations to the following:

  • Holes for surface-applied hardware – applied to the door or frame without removing material other than drilling round holes to accommodate cylinders, spindles, and similar operational elements, electrified hardware (added in the 2016 edition), as well as through-bolts.
  • Function holes for mortise locks
  • Holes for labeled viewers
  • Maximum ¾-inch wood and composite door undercutting
  • Installation of protection plates

Previous editions of NFPA 80 limit the maximum diameter for round holes drilled in the field to 1 inch, except cylinders which may be drilled in the size necessary to accommodate the cylinder.  The 2016 edition includes the same limitation, but a new paragraph was added which allows larger holes for surface-mounted hardware to be drilled in the field in accordance with the listings of the door and hardware manufacturers.  The 2019 and 2022 editions are consistent with the 2016 edition in this respect.  Before drilling larger holes it is important to verify with the manufacturers whether their listings allow these to be drilled in the field.

NFPA 80-2016 also added a paragraph regarding job-site preparation for raceways drilled across the width of the door to carry wires from electrified hardware to an electric hinge or power transfer.  This preparation may be performed at the job site in accordance with the door manufacturer’s listings, and when permitted by the listing laboratory (for example, Underwriters Laboratories or Intertek).  If a door manufacturer’s listings do not include provisions for drilling raceways, the raceway is considered a field modification (see below).

Field Modifications

In the 2013 edition of NFPA 80, a definition for field modifications was added:  “Changes, not otherwise permitted by this standard, made to a listed assembly or component after it has been manufactured.”  This definition, along with additional information in Annex A, make it clear that the acceptable job site preparations listed above are not considered field modifications.

Field modifications are addressed in Section 5.1.4 of the 2013 edition of NFPA 80, and Section 5.1.5 of the 2016 and 2019 editions.  For changes made in the field that are above and beyond those allowed as job site preparations, permission may be requested in advance by contacting the manufacturer of the component being modified; the manufacturer will then contact the appropriate listing laboratory with a written or graphic description of the modifications.  For example, most electric strikes require a rectangular cutout in the face of the frame.  Permission to make this modification in the field may be approved by the listing lab, after permission is requested through the frame manufacturer.  Raceways would also require pre-approval if the door manufacturer’s listings do not address raceways drilled in the field.

If the manufacturer of the component being modified is no longer available, the lab may be contacted directly, and an engineering evaluation supporting the field modification may be provided.  A field visit from the listing laboratory is not required if permission for the field modification is granted by the lab.  If modifications are made without prior approval, the doors and/or frames may need to be re-labeled by the listing laboratory, which will include a site visit and inspection and can be costly.

Filling Holes

Job site preparations and field modifications sometimes result in holes left in the surface of the door or frame due to the removal of existing hardware.  In the 2013 edition and prior, NFPA 80 requires holes to be repaired by one of two methods: install steel fasteners that completely fill the holes, or fill the screw or bolt holes with the same material as the door or frame.  The standard seems to be addressing only holes from fasteners and this was confirmed in the 2016 edition when the language was changed slightly to state, “When fastener holes are left in a door or frame…”

The 2016 edition also added a third method for filling fastener holes – “Fill holes with material listed for this use and installed in accordance with the manufacturer’s procedures.”  This acknowledges the use of caulk or other materials that can be used to fill holes, but only if the material is listed for filling holes in fire doors.  If a product has been tested and listed for filling voids in walls or other surfaces, that does not necessarily mean that it can be used to fill holes in fire door assemblies.  At this time, there are very few products that have been listed for use in fire doors and there are strict limitations on where it is used; it’s important to verify the manufacturer’s listings regarding the size of the hole, the door or frame material, and the rating of the assembly.  While previous editions of the standard did not specifically mention the use of a filler material, it may be allowed as an equivalency (NFPA 80 Section 1.4).

Holes that are not fastener holes are considered a field modification.  This means that approval for the repair must be obtained from the listing laboratory, via the door or frame manufacturer.  To determine whether an existing hole may be covered by a filler plate, or whether covering existing holes with new hardware is sufficient, the door or frame manufacturer should be contacted to ensure that the proposed solution is acceptable.  If alterations are conducted in compliance with NFPA 80, the fire door assembly is not typically required to be re-labeled in the field, but beginning with the 2013 edition of NFPA 80, a fire door assembly inspection must be conducted after maintenance work is completed.  The 2013, 2016, and 2019 editions of the standard also require inspections after installation of the assembly, as well as annually.


When preparing to perform a field modification or when questions arise, it’s best to avoid problems by conducting research and planning in advance. While NFPA 80 gives some direction with regard to protocols that must be followed when making alterations in the field, to get definitive answers you may have to contact the manufacturer of the component being modified, or even the listing laboratory on the label.  The door or frame label will contain helpful information to identify the manufacturer and testing lab, along with a number which can be used to obtain more detailed specifications.  The manufacturer should be the starting point for most requests, and then the listing laboratory.  The Authority Having Jurisdiction may also be contacted for assistance.

You need to login or register to bookmark/favorite this content.