
Vertically Stiffened Fire Doors
A 1¾-inch custom steel door with vertical stiffeners and fiberglass insulation between stiffeners. Designed for high-abuse openings with center-seam and optional seamless construction.
- Internal Construction
- 22-gauge vertical steel stiffeners spaced no more than 6 inches apart and welded to both face sheets at no more than 5 inches on center, with fiberglass insulation between stiffeners.
- Door Thickness
- 1¾ inches (44.5 mm), with 16-gauge steel top and bottom channels welded to both face sheets.
- Face-Sheet Gauges
- 18 gauge Heavy Duty, 16 gauge Extra Heavy Duty, 14 gauge Maximum Duty, and 12 gauge ANSI / NAAMM construction.
- Steel & Coating
- ASTM A1008 cold-rolled steel or ASTM A924 / A653 hot-dipped galvanized steel with A60 or G90 options.
- Standard Sizes
- Singles from 2'0" to 5'0", pairs from 4'0" to 10'0", and heights from 6'8" to 12'0", subject to gauge and configuration.
- Fire Rating
- 20 minutes through 3 hours. Maximum rated sizes vary by labeling agency and configuration; confirm against the datasheet before final selection.
- Performance
- STC 38 with 18-gauge face sheets to ASTM E90 / E413, plus ANSI A250.4 Level A physical endurance up to 1,000,000 cycles at 4'0" × 10'0" maximum size.
- Hardware Preparation
- 4½- or 5-inch hinges with 7-gauge reinforcement to ANSI A156.7, plus cylindrical or mortise lock preparation to ANSI A115.
Suggested use: schools and training centers, institutional and government facilities, factories, warehouses, transportation terminals and vehicle service facilities.














