Middle Atlantic MRK-4031LRD 40U Open-Frame Floor-Standing AV Rack
Overview
The Middle Atlantic MRK-4031LRD is a 40U open-frame floor rack designed for high-density AV, security, and IT equipment installations where load capacity and seismic compliance are non-negotiable. At 31 inches deep with 29 inches of usable depth, this frame accommodates full-depth NVRs, patch panels, power distribution units, and switching equipment without forcing cable-management compromises. The MRK-4031LRD ships as a frame-only configuration — no side panels, no rear door — making it the right choice for environments that prioritize airflow and front/rear access over physical security of the enclosure. Rack rail type is 10-32, which is the standard threading for most commercial AV and security hardware. TAA compliant and manufactured in the USA, it qualifies for government and federally-funded projects where domestic sourcing is required.
Compatibility
The 19-inch panel width and 10-32 threaded rails are compatible with virtually all standard EIA-310 rack-mount equipment: network video recorders, PoE switches, UPS units, KVM systems, patch panels, and cable management accessories. The 40 RU of usable rack space (70.13 in usable height) suits mid-to-large security control rooms, broadcast infrastructure closets, and enterprise AV head-end rooms. The MRK series from Middle Atlantic is designed to gang side-by-side — the gangable construction means you can bolt multiple frames together for multi-bay deployments without gaps or misalignment. Compatible with Middle Atlantic's accessory ecosystem including side panels, doors, and vertical cable managers sold separately.
Installation Notes
The MRK-4031LRD is rated to UL Load Capacity of 2,500 lbs — enough for fully populated dense configurations — with a static weight capacity of 10,000 lbs, which matters for seismic anchor calculations. Seismic rating meets ASCE 7-10 requirements; verify your local jurisdiction's seismic zone before specifying this as a compliant installation. The frame arrives unassembled; plan for at least two technicians given the 133 lb shipping weight. No rear door means cable egress planning is straightforward, but physical access control to rear-mounted equipment must be handled at the room level. All mounting hardware for PDUs, cable managers, and blanking panels is sourced separately.
