36 Constellation ES Series SAS Product Manual, Rev. F
7.5 Environmental limits
Temperature and humidity values experienced by the drive must be such that condensation does not occur on
any drive part. Altitude and atmospheric pressure specifications are referenced to a standard day at 58.7°F
(14.8°C). Maximum wet bulb temperature is 82°F (28°C).

7.5.1 Temperature

a. Operating
The drive meets the operating specifications over a 41°F to 140°F (5°C to 60°C) drive case temperature
range with a maximum temperature gradient of 36°F (20°C) per hour.
The maximum allowable drive case temperature is 60°C. See Figure 10 for HDA case temperature
measurement location.
The MTBF specification for the drive assumes the operating environment is designed to maintain nominal
case temperature. The rated MTBF is based upon a sustained case temperature of 104°F (40°C).
Occasional excursions in operating temperature between the rated MTBF temperature and the ma ximum
drive operating case temperature may occur without impact to the rated MTBF temperature. However,
continual or sustained operation at case temperatures beyond the rated MTBF temperature will degrade the
drive MTBF and reduce product reliability.
Air flow may be required to achieve consistent nominal case temperature values (see Section 11.2). To con-
firm that the required cooling is provided for the electronics and HDA, place the drive in its final mechanical
configuration, and perform random write/read operations. After the temperatures stabilize, measure the
case temperature of the drive.
b. Non-operating
–40° to 158°F (–40° to 70°C) package ambient with a maximum gradient of 36°F (20°C) per hour. This
specification assumes that the drive is packaged in the shipping container designed by Seagate for use with
drive.
Figure 10. Location of the HDA temper ature check point
Note. Image is for reference only, may not represent actual drive.

7.5.2 Relative humidity

The values below assume that no condensation on the drive occurs.
a. Operating
5% to 95% non-condensing relative humidity with a maximum gradient of 20% per hour.
b. Non-operating
5% to 95% non-condensing relative humidity.