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The MU Series multi-use flush frames meet demands for light to maximum duty applications in commercial and industrial buildings. They are ideal for interior and exterior locations, for virtually any wall construction. They feature a jamb profile similar to that of the DW Series frames, but is designed for installation as part of the wall framing sequence.

The MU Series frames may be specified and/or supplied as knock-down (KD) for field assembly before installation or welded for installation as a complete unit.  




Strength, durability and ease of installation

  • Die-mitered corner connections of the MU Series multi-use flush frame corners lock together once the frame is installed. The tab/lock design:
    • Prevents the head from rising
    • Keeps the head and jamb members in alignment
    • Keeps the miter tight
    • Includes wedge-lock corner clips. Screws are supplied to secure miter
  • Patented universal hinge preparations allow for easy field conversion from standard weight .134" (3.3 mm) thick hinges to heavy weight 0.180" (4.7 mm) hinges
  • Adjustable base anchors allow for installation adjustment when the floor is not level
  • Factory prepared for field installed silencers
  • Factory-applied baked-on rust inhibiting primer in accordance with ANSI A250.10-2011

Exceeds industry standards

  • Steelcraft is SDI Certified through regular audits to ensure manufacturing, performance and quality standard set by the Steel Door Institute
  • Overall frame construction exceeds ANSI A250.8-2017 (SDI-100), the standard set by SDI specifying sizes, design, materials, construction, finishing and performance for standard commercial steel doors and frames
  • Hardware preparations and reinforcements meet ANSI A250.6-2003, and locations meet ANSI/DHI A115, unless otherwise stated
  • Frames meet fire rating requirements; they are listed for installations requiring compliance to both neutral pressure testing (ASTM E152 and UL-10B) and positive pressure standards (UL-10C)
  • Factory-applied baked-on rust inhibiting primer meets ANSI A250.10-2011

Typical applications

Stud wall application when there is a desire to install the frame as part of the wall framing sequence (typical of masonry frames). Unlike F Series frames, the MU Series provides backbend returns similar to the profile of DW or K Series drywall frames so that drywall can more easily slide into place between the stud wall and steel frame. MU Series also allows welding unlike DW or K Series, so is the only way to get a welded corner with a backbend return.

Technical Data Guide

For more complete information on MU Series Frames, download the Steelcraft Technical Data Manual.

  • MU Series (Pages 33-36): Includes Anchors, Hardware Preps, Lights, Fire Ratings



   Fire Rated




Steelcraft Technical Data Manual