The Detex F90KR 7FT is a 7-foot fire-rated keyed removable mullion for pairs of commercial doors equipped with compatible rim-type fire exit devices. Part of Detex's 90 Series, this heavy-duty center mullion creates a secure strike-mounting member between two door leaves while allowing authorized personnel to remove the center post quickly when the full opening width is needed. The unit is manufactured from 11-gauge, 2-inch × 3-inch steel tubing in a paintable primer-gray finish and includes the F90KR keyed removable upper mechanism and compatible standard factory mounting components.

3-Hour Fire-Rated Mullion: The F90KR (the "F" indicates fire-rated) is listed by Detex under UL 10B / UL 10C and Intertek/Warnock Hersey for use in approved fire-rated pairs of doors up to 8 feet wide × 8 feet high, with up to three-hour fire protection when installed as a properly listed and approved complete opening. The 7FT version is intended for a door opening approximately 84 inches high, with field fitment to follow the current Detex installation instructions. The mullion's rating does not independently make an unrated door fire rated: both door leaves, frames, closers, rim fire-exit devices, strikes, and installation must satisfy the full assembly listing.

Keyed Removal Without Removing Screws: The frame-mounted top fitting incorporates the F90KR locking head and permits authorized removal of the mullion by turning a key once. Once the mullion is released, the steel post can be lifted out of the lower fitting to restore full doorway clearance for moving equipment, deliveries, facility maintenance, or other approved temporary access. Reinstallation is accomplished by seating the post and snapping it back into the locking head without using the key. The small-profile bottom/base fitting reduces interference in the doorway when the post is removed. The locking cylinder is positioned inside the building to reduce access from the outside.

Rim Cylinder Sold Separately: Detex ships the standard keyed removable mullion without the rim cylinder unless the factory or dealer expressly specifies a cylinder option. Select a compatible rim cylinder and appropriate keying to operate the mullion's release head; verify cylinder dimensions, tailpiece length, cam/drive, housing and key system with the manufacturer's current F90KR instructions before ordering. This product is not supplied with a complete panic exit device, a pair of rim strikes, a door leaf, or a door frame.

SHK1 Fire-Exit Strike Hook Kit: Detex identifies the SHK1 strike hook kit as standard with its fire-rated removable mullion. This component is part of the fire-rated application and must be installed and matched to the chosen rim devices and approved strike arrangement. Detex permits field location and preparation of the strike on the F90KR according to the listed hardware and approved templates. Confirm actual strike model, device manufacturer, hook installation and the requirements of the fire-exit assembly before cutting or drilling.

Primer Gray Steel Construction: The 11-gauge steel mullion tube is built for high-use commercial openings and is finished in standard gray shop primer for field painting to match the frame or door. It is not satin stainless steel 630, polished brass, electrified, or automatically weatherized. The upper fitting mounts to the head frame, while the small-profile lower shoe/base is anchored to the floor with manufacturer-specified anchors and shims. Detex's mounting design avoids the need to drill the mullion tube during standard assembly.

Key Features and Benefits

• Detex F90KR 7FT: Genuine 90 Series fire-rated keyed removable center mullion for 7-foot paired commercial doors.
• Up to three-hour fire-rated listing: Intertek/Warnock Hersey and UL 10B/10C listing for approved pairs up to 8 ft wide × 8 ft high, subject to full opening construction.
• Heavy-duty 11-gauge steel: 2 in × 3 in rectangular steel mullion tube, designed for demanding commercial use.
• 84-inch nominal door height: Designed for compatible standard seven-foot door openings, with post length and field adjustment specified by Detex.
• Quick keyed release: One key turn releases the mullion for removal without taking out frame- or floor-mounting screws.
• Snap-back reinstallation: Refit and lock the post into its frame-mounted top fitting without turning the key.
• Inside-mounted cylinder: Lock cylinder location inside the building reduces unauthorized exterior manipulation.
• Rim cylinder is optional / sold separately: Match compatible keying and cylinder hardware to the site before ordering.
• Frame-mounted locking head: Locking mechanism remains attached at the header when the post is temporarily removed.
• Low-profile base fitting: Small bottom footprint is intended to minimize obstruction when the mullion post is removed.
• Installer-friendly hardware: Base anchors, mounting components and recommended fitting arrangements support new and retrofit door installations.
• Fire-rated SHK1 strike hook kit: Detex documents the strike hook kit as standard equipment on the F90KR fire-rated version.
• Field strike preparation permitted: Detex's rated-mullion listing allows installation-specific strike positioning when performed according to manufacturer and listing requirements.
• Paintable gray primer: Standard finish can be field coated to match commercial frames and doors following preparation guidance.
• Rim exit device compatibility: Designed for Detex Advantex, Value Series and certain other approved manufacturers' listed rim fire-exit devices; approval must be checked for the exact hardware combination.
• Full-opening accessibility when removed: Convenient for oversized deliveries, equipment movement and maintenance, provided the opening's egress/fire-door controls are managed safely.
• No mullion-tube drilling for basic assembly: Uses specialized top/bottom fittings and factory mounting hardware.
• Field fitment: Detex provides mullion cutting and installation instructions; preserve required clearances and fire-listing conditions.
• Different from 90KR: F90KR is the specifically fire-rated keyed removable series; the standard 90KR is not the specified fire-rated product.
• Different from F90R: F90KR is key-removable, unlike the conventional screw-removable F90R assembly.
• Non-electrified: No electrical transfer, contacts, powered release or access-control electronics included.

Technical Specifications

Where to Use the F90KR 7FT

• Fire-rated paired hollow-metal doors: Used with correct fire-exit rim hardware and fire-listed door/frame arrangement.
• Healthcare and institutional facilities: Doorways requiring secure daily operation with occasional unobstructed full-width clearance.
• Schools and government facilities: Heavy-traffic double doors with keyed removable center posts.
• Warehouse and loading access: Rated personnel-door pairs that must accommodate oversized equipment at controlled times.
• Commercial offices and public facilities: Paired exits requiring compatible rim strikes and scheduled maintenance access.
• Retrofit of approved mullion systems: Replacement or upgrade where header/base mounting, fire-door listing and strike preparation are compatible.

What's Included

One Detex F90KR 7FT fire-rated keyed removable 7-foot steel mullion assembly consisting of the primer-gray steel center post, manufacturer-standard keyed-release top fitting and cylinder housing (less operating cylinder), low-profile bottom base fitting, base anchors and mounting/shim components per the current factory kit. The SHK1 strike hook kit is identified by Detex as standard with the fire-rated F90KR. Verify actual supplier carton contents and required strike hardware before installation.

Not Included Unless Specially Ordered

Rim cylinder, cylinder keys, keyed-alike service, Detex or other rim exit devices, matching rim-device strikes (unless separately specified), doors, frames, closers, door hardware, field painting, site-specific fire protection components and installation labor are not included. The keyed-release mechanism is part of the mullion hardware, but the operating cylinder itself must be purchased separately unless factory equipped.

Installation & Fire-Protection Notes

Model decoding: F90KR = fire-rated, keyed removable 90 Series center mullion; 7FT = seven-foot door-height version. Follow manufacturer instructions for header/frame strength, the top fitting attachment, lower base anchorage, field tube sizing and strike location, the SHK1 hook kit, cylinder/tailpiece selection and the exact approved rim fire-exit device combination. Removing a mullion from a protected fire door pair affects its latching arrangement; keep the assembly correctly installed and latched whenever fire-door performance is required. The mullion is not an exit bar, outside trim, or a 630 stainless finish. Before publication and shipping, verify the 42 lb provisional weight, actual oversized carton dimensions, long-package carrier surcharges and the current Detex/SECLOCK factory package contents.