Window and curtain wall mullions, transoms and systems

An operable window system comprising:

• a metal mullion or transom first structure configured to receive an operable window, the first structure comprising:
• a first thermally insulated polymer component connected to a side of the first structure at a side wall and spanning substantially a total width of the first structure;
• and
• a second thermally insulated polymer component positioned at a top wall of the first structure and connected to a second metal structure;
• and
• an operable window configured to close to a position defining a gap between the window and the second thermally insulated polymer component, at least one seal positioned in the gap and abutting both the operable window and the second thermally insulated polymer component.

An operable window system comprising:

• a metal frame structure configured to receive an operable window, the frame structure comprising:
• a first thermally insulated polymer component connected to a side of the frame structure at a side wall and spanning a total width of the side wall;
• and
• an operable window having a second thermally insulated polymer component connected to a sash assembly, the window configured to close to a position defining a first gap between the second thermally insulated polymer component and the first thermally insulated polymer component and a second gap between the sash assembly and the frame structure, at least one seal positioned in the first gap and abutting both the second component and the first component and at least one seal positioned in the second gap and abutting both the sash assembly and the frame structure.