Hollow Metal Borrowed Lite Window Frames

What is a Borrowed Lite Window Frame?

A "HM borrowed lite window" refers to a fixed window frame made of hollow metal, designed to allow light to pass from one room to another within a building, essentially acting as a "borrowed lite" feature in interior design; "HM" is standard for "hollow metal" and "borrowed lite" indicates the function of letting light through without an operable window opening. 

Key points about a HM borrowed lite window:
  • Function: Primarily used to bring natural light into a room that might not have direct access to windows by borrowing light from an adjacent space.

  • Construction: Made from a hollow metal frame, which is a common material for commercial doors and interior wall framing.  Available from MDI as KD (Knock-Down Construction) or as WF (Welded Construction).

  • Fixed glass: The window is typically fixed, meaning it cannot be opened, as its main purpose is to transmit light, not ventilation.