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Fire-Rated Diamond Tread Floor Door

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The Nystrom fire-rated architectural pan door is the industry's leading solution to offer larger sizes and fire-rated safety for new construction or replacement projects.


  • 2- or 3-hour fire ratings tested to NFPA 288
  • Sizes up to 52" x 96"
  • Lock options for added security
  • Improved interior release handles
  • Installs in wood or concrete applications



Model FDF L/P
Load 250 psf live load for sizes up to 48" x 60"
150 psf live load for sizes above 48" x 60" up to a maximum of 52" x 96"
Door Single
Material Aluminum: 1/4 inch, mill finish
Cover Diamond tread plate
Fire-Rating 2-hour or 3-hour
Frame Angle Frame, Thermally Broken
Installation Cast-In or Bolt-In
Spring Enclosed coil, Type 17-7 Stainless Steel
Hinge Heavy-duty Type 316 Stainless Steel butt hinge
Latch Slam latch zinc-plated steel with inside lever handle
Compliance NFPA 288, Warnock Hersey label tested and listed by Intertek
Options Self-closing mechanism, recessed padlock hasp, mortise prep
Warranty 5 years

Order Guide

Use the table below to guide specification of available options. The part number components are indicated in BOLD ORANGE text.

Fire Rated Diamond Tread Floor Door



P - 250 psf
L - 150 psf
A - Aluminum 24" – 48" (250 psf)1
48" – 52" (150 psf)2
24" – 60" (250 psf)
60" – 96" (150 psf)


S - Single Door
W - Anchors Provided
L - Handle
3HR - 3 Hour rating3
BI - Bolt-in Installation4
MC6 - Mortise Lock
PR - Recessed padlock hasp
SC - Self closing mechanism

1The load will default to "P" (250 psf) for doors up to and including 48" x 60" (e.g. FDFPA36x36SWL)
2The load will default to "L" (150 psf) for doors greater than 48" x 60" (e.g. FDFLA50x75SWL)
3Up to 48" x 60" only and 250 psf only
42-hour only


NYSTROM warrants all Floor Doors to be free from manufacturing defects in materials, factory finishes, and workmanship for a period of five (5) years from the date of shipment.

Should a product fail to function in normal use within this period, Nystrom shall furnish a replacement or new part at Nystrom's discretion. Failure to use product in methods consistent with Nystrom product manuals shall relieve Nystrom of any liability. Our liability under this warranty excludes installation or removal costs involved in the product replacement and excludes any responsibility for incidental or consequential damage of any nature.

For information on a warranty claim, please visit our Warranty Support section or call 800-547-2635.

Warranty Support


Coming soon.

Replacement Parts

Download the retrofit kit drawing below for replacement parts

Retro Kit

Description Model Size Shop Drawing CAD BIM DataSheet 3-Part Specs LEED Installation Warranty
2-Hour Cast-in FDF < 48x60 PDF DWG LINK PDF WORD PDF PDF
2-Hour Bolt-in FDF < 48x60 PDF DWG LINK PDF WORD PDF PDF
2-Hour Cast-in FDF > 48x60 PDF DWG LINK PDF WORD PDF PDF
2-Hour Bolt-in FDF > 48x60 PDF DWG LINK PDF WORD PDF PDF
3-Hour Cast-in FDF < 48x60 PDF DWG LINK PDF WORD PDF PDF

PDF Product Change Notice - 04/16/2021