EFCO Special Purpose Windows Installation - Manual (Page 16)

EFCO CORPORATION 3/5/2014 PART NO. YW40 Page 6 of 7
Window Installation Instructions - Basic Window Installation Section -
Installation of Mullions When Not Using Subframe or Panning
1. Refer to the shop drawings for the correct center line location of the mullion.
2. For elevations not using Subframe or Panning, mullions are supplied at the rough opening height
plus 2” (square cut) to allow for field trimming as required
3. Set the mullion into the opening. Plumb the mullions to the opening. Fasten the mullion to the
opening by using two EFCO supplied mullion anchor clips (KA20). Locate one clip at the masonry
head and one at the masonry sill. Attach the clips to the opening with erector furnished fasteners,
then attach the mullion to the mull anchors with EFCO furnished fasteners.
4. Back bed the window to mullion contact area with silicone sealant before installing the window, or
cap seal after the window is installed.
5. Attach the mullion pressure clips to the mullion as close to the top end as possible, and then 16” on
center with EFCO supplied fasteners. Spacing may need to be reduced depending on design
pressure and anchorage conditions. Refer to the approved shop drawings or consult the project
design professional.
Attach the 4” mullion pressure clips to the mullion at the bottom end. The 4” clip should contact the
sill flashing or other adjoining horizontal surface. This bottom clip forms a water dam under some
opening conditions. Seal the clip to the condition at the sill and up the sides. The screw heads on
this bottom clip should also be sealed over.
6. Attach the mullion clips to each window jamb with EFCO supplied fasteners. Make sure the window
jamb remains square and plumb. (Field drilling of window jambs by the erector.)
7. Field cut the vertical mullion cover to fit between the opening conditions and snap over the mullion
clips.
Check the overall frame dimensions on every 5
openings on long runs to avoid dimensional build-up.
Overall opening dimension
Completely read the General Installation Instructions and all other sections which pertain
to your project before starting work. These recommendations are for general erection
procedures only. For actual job conditions, see the details on the shop drawings. For
perimeter anchor types and spacing, refer to the approved shop drawings or consult the
project design professional.