·	GENERAL: Doors shall be SN-24 Series as manufactured by Mid-America Door Company.

·	DOOR SECTIONS: Sections will be 25 gauge steel and have a nominal 2” thickness. Sections will have a tongue and groove meeting rail to provide a weather tight seal between sections. Center and end stiles will be 18 gauge steel formed, fastened, and bonded as integral structures of the section.

·	TRACK: Galvanized steel track systems shall be 2" or 3" depending on door size and will be bracket or angle mounted depending upon application.

·	HARDWARE: Hinges and brackets to be made from galvanized steel. Each roller shall have ¼" hardened steel balls per roller, or adequate for design requirements.

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SPRING COUNTERBALANCE: Springs shall be oil tempered, helical wound and stress relieved torsion type. Springs will be mounted on a continuous cross header steel shaft supported by bearing brackets. Long life springs of 25-50-100 thousand cycles may be specified and are recommended for high usage doors. Cables are 7 x 19 strand galvanized aircraft type with a minimum safety factor of 8 to 1.

·	FINISH: Paint will be baked on polyester coating.

·	WEATHER-STRIP: Bottom rail of section to include U'd vinyl astragal held in place by retainer to provide additional reinforcement. Additional weather-stripping available for full width of header and jambs assisting in preventing air infiltration.

·	LOCK: Lock will be interior mount slide lock. (Optional cylinder lock available)

·	VISION SECTIONS: Full section glazing can be provided with mill finish aluminum frames and DSB glass to allow maximum light or vision, or 25 x 5 vinyl frames, or rubber grommet glazes with DSB glass.

·	INSULATION: Insulation may be specified for the SN-24 series. Door sections shall be furnished with minumum 1½” thick polystyrene insulation. Back covers shall be 26 gauge steel, or vinyl backed.