ES 4250 Storefront Systems
THERMALLY BROKEN
ES 4520 is a thermally broken center glazed storefront system for insulated glass. This product can be assembled with screw spline or shear block construction, and is compatible with ES-21 and ES-35 doors. Frames are factory fabricated and shipped “knock down” or pre-assembled for field glazing. It is also available in non thermal option for 1/4” monolithic glass.

System Description
- Frame Depth: 4-1/2″
- Sight line: 2″
- Designed for 1” insulated glass (Thermal) or 1/4” monolithic (Non Thermal)
- Design load: +30/-30 psf
- Water infiltration: 10 psf
- Maximum size:
- U Value: 0.45 (with 1/4 SB60 – 1/2 air – 1/4 clear)
Features
- Inside or outside glazed
- Pour and debridge thermal break
- Integral Door Adaptor
- Screw spline or shear block fabrication
- High performance sill flashing
- Anodized, painted or wood grain finishes available