Overview
This document provides detailed specifications and features of the EFCO Corporation's Series 660 Single Hung, Series 670 Double Hung, and Series 6600 Fixed Heavy Commercial Hung Thermal Windows. These windows are designed for both historical replication and new construction, offering flexibility in design and energy efficiency.

Specifications
- Frame and sash constructed from 6063-T6 aluminum alloy with a depth of 3 7/8".
- Thermal barrier in frame and sash for improved thermal performance.
- Accommodates glazing units from 1/8" to 1 1/4" depth.
- Dual glazing options with optional integral blinds.
- Available in anodized or painted finishes.

Performance Ratings
- AAMA Heavy Commercial and Architectural Grade ratings.
- Air infiltration: <.10 cfm/sf @ 6.24 psf.
- Water resistance: No leakage @ 12.0 psf.
- Structural performance: ±75.0 psf.
- U-Value (NFRC-102): .51G.

Features and Benefits
- Enhanced energy-saving potential and U-Value performance.
- Superior air and water performance with improved air infiltration resistance.
- Flexibility in design requirements for glazing.
- Low maintenance with increased convenience.
- Stronger, more durable screens.
- Allows matching of existing sight lines in restoration projects.

Hardware and Accessories
- Sweep locks, automatic head and sill locks, and pole ring sweep locks available.
- Screen frames made of extruded aluminum alloy, available in full or half screens.
- Accessory line includes subframes, mullions, and architectural sills.

Glazing Options
- Inside or outside glazed sash with extruded aluminum snap-in glazing bead.
- Dual glazing available in 1/8", 3/16", and 1/4" glass.
- Between-the-glass 5/8" aluminum blinds available with dual glazed windows.

Conclusion
The EFCO Corporation's window series offers a comprehensive solution for fenestration needs, combining aesthetic appeal with robust performance and energy efficiency. The variety of configurations and customization options make it suitable for a wide range of architectural applications.