Hitachi GR2000 Series Installation Manual page 313

Heated air from the other device may be taken into this router, causing the
intake air temperature to exceed the router's environmental requirements.
When the air intake or exhaust force of the other device is too strong, a rever
pressure on this router's intake air may arise, decreasing the cooling efficienc
this router.
Should such adverse effects take place on this router, malfunction or failure may
result. Take necessary measures, e.g., place these devices duly apart from each ot
or put a partition between them so that their airflows do not interfere with each
other.
5.2.7.3 Cooling Requirements for Rack-Mount Installation
To guarantee the airflow through the router for cooling, secure enough space
between the router and the structure of the rack as shown below. If not, malfunct
or failure may result.
GR2000-4, GR2000-2S, GR2000-4S and GR2000-6H: 50 mm or greater each
from the left side and the right side of the chassis.
GR2000-10H, GR2000-20H, GR2000-10, and GR2000-20: 50 mm or greater
each from the left side and the right side of the chassis, and 300 mm or great