Figure 52: Typical Open-Frame Rack - Juniper T640 Hardware Manual

Chapter 9: Preparation Overview
The rack rails must be spaced widely enough to accommodate the router chassis's
external dimensions: 37.45 in. (95.1 cm) high, 31 in. (78.7 cm) deep, and 17.43 in. (44.3 cm)
wide. The outer edges of the mounting brackets extend the width to 19 in. (48.3 cm). The
spacing of rails and adjacent racks must also allow for the clearances around the router
and rack that are specified in "T640 Clearance Requirements for Airflow and Hardware
Maintenance" on page 122.
The chassis height of 37.45 in. (95.1 cm) is approximately 21.4 U. A U is the standard rack
unit defined in Cabinets, Racks, Panels, and Associated Equipment (document number
EIA-310-D) published by the Electronics Industry Association. You can stack two routers
in a rack that has at least 42.8 U (74.9 in. or 1.90 m) of usable vertical space.
The rack must be strong enough to support the weight of the fully configured router, up
to approximately 565 lb (256.3 kg). If you stack two fully configured routers in one rack,
it must be capable of supporting about 1130 lb (512.6 kg).

Figure 52: Typical Open-Frame Rack

Always secure the rack to the structure of the building. If your geographical area is subject
to earthquakes, bolt the rack to the floor. For maximum stability, also secure the rack to
ceiling brackets.
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