The units are available in 30- x 30-in. and 36- x 36-in. sizes. Light in weight (the basic 30- x 30-in. door weighs 100 lb), it consists of just two parts: an adjustable frame and a removable door. The frame fits 6-in., 8-in. or double-stacked block stopping walls. Any LC 13 assembly can be repositioned quickly when ventilation paths change.

“The LC 13 is all about keeping things simple,” Cassidy said. “First, it has a new, no-flange back frame that makes installation and disassembly a snap, because the door assembly can slide into or out of a wall without disturbing the wall itself. And we’ve retained the easy setup features that made the original Zero Door so successful.”

“Whether the LC 13 is used as a basic mandoor or as part of an airlock system, two guys can install it using just one tool,” he said. “For airlock installations, we supply a patented adapter kit that connects two LC 13s back-to-back. Either way, installation time is only about one hour per door.”

To promote movement between high- and low-pressure spaces, the LC 13 comes with a built-in equalizer port that doubles as a rock-dusting access point. Other standard safety features include:
• An exclusive auto-close mechanism that eliminates slamming and keeps body parts out of harm’s way;
• Secure, double-latching handles that are engineered to take day-to-day punishment without snapping off;
• Latches that can be operated from either side of the door without jamming;
• Rolled edges that won’t snag skin, clothes or equipment; and
• High-visibility warning reflectors.

Once it’s latched, Cassidy said, the LC 13 seals tightly at all four corners for maximum ventilation control. A long-lasting fiberglass gasket stays airtight and minimizes maintenance. Like all Zero Door models, the LC 13 is precision-engineered and the most solidly built product in its class, he said. Heavy, galvanized 10-gauge tubular steel frames and 14-gauge door panels afford outstanding resistance to convergence and heaving.

“Field tests show the LC 13 can give you up to three times the service life of conventional doors, with a lot less maintenance,” Cassidy said.