WB FD 8500 Series

Flush Fire-Rated Aluminum Diamond Plate Floor Hatches

Sizes & Specifications

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Williams Brothers - WB FD 8500 Series Flush Fire-Rated Aluminum Diamond Plate Floor Hatches

Flush, Aluminum Diamond Plate Floor Hatch Comes with a 2 Hour Fire Rating!

The WB FD 8500 Series Flush Fire-Rated Aluminum Diamond Plate Floor Hatch is a rugged, flush access door designed for new or existing openings in interior utility and general purpose applications. In subways, skyscrapers and everything in between, the WB FD incorporates the latest fire-resistant technology to protect floors above from fire below. Featuring a heavy-duty, 1/4″ reinforced aluminum cover and an aluminum/stainless steel thermal-break frame both with a mill finish, hatch is Warnock-Hersey tested for a 2 hour fire rating. In addition, it is reinforced for pedestrian traffic and can safely handle 150 pounds per square foot (psf) loading.


  • Cover: 1/4″ Reinforced Aluminum Diamond Plate with Thermal-rated Composite Fire Panel
  • Frame: Thermal-break Frame with Aluminum Upper Frame and Stainless Steel Lower Frame
  • Finish: Mill finish
  • Handle: Cast Aluminum Flush Lifting Handle
  • Latch: Two-point Slam Latch
  • Hinge: Type 316 Stainless Steel
  • Lift Assistance: Stainless Steel Compression Springs Contained Within the Door Assembly
  • Automatic Hold-open and Closing Mechanism: 316 Stainless Steel Hold-open Arm Automatically Keeps the Cover in its Open/Upright Position at 90°
  • Automatic Closing Mechanism:  Mechanism to Automatically Close and Latch the Cover When Heat Breaks a 165° F Fusible Link
  • Fusible Link: UL-listed 165° F Fusible Link
  • Hardware: 316 Stainless Steel Nuts and Bolts
  • Loading: 150 psf (732 kg/m2) Live Load
  • Fire Rating: Warnock-Hersey Tested for a 2 Hour Fire Rating, Tested to NFPA 288 (ASTM E119)
  • Installation: Door is designed for Dry, Interior Locations Only


  • Construction: Steel
  • Custom Sizes: Available on Request


The WB FD 8500 fire-rated floor door is available in a variety of sizes including 24×24, 24×36, 30×30, 36×36, 36×48 and more. In addition, custom sizes are available upon request. Door features a flush lifting handle, slam latch, stainless steel hinges, automatic closing mechanism with a UL listed fusible link, stainless steel compression springs for lift assistance, and an automatic hold-open arm. Options include steel construction.

Manufactured for The Williams Brothers Corporation of America. MADE IN USA.