The FPC slot-0 and slot-11 on the MX960 router are not NEBS compliant beyond 104°F (40°C). This article explains that this is a cooling restriction.
This article affects only the following MPCs:
MPC4E: MPC4E on MX Series Routers Overview
The operation of the FRU (installed onto FPC slot-0 and slot-11) is not guaranteed if the ambient temperature exceeds 104°F (40°C). If the ambient temperature continues to rise beyond 104°F (40°C), there could be overheating conditions at higher temperatures, exceeding chassis thresholds and resulting in shutdown conditions.
This is a cooling restriction.
The ambient temperature of 104°F (40°C) is measured at CB-slot 0 and 1 "Intake" and correlated to each FPC in an MX chassis.
user@lab-mx960-01> show chassis environment | match intake <snip> CB 0 Intake OK 27 degrees C / 80 degrees F CB 1 Intake OK 27 degrees C / 80 degrees F CB 2 Intake OK 27 degrees C / 80 degrees F FPC 0 Intake OK 30 degrees C / 86 degrees F FPC 1 Intake OK 29 degrees C / 84 degrees F FPC 5 Intake OK 30 degrees C / 86 degrees F