HDD User's Guide --- Chapter 3, Environmental Conditions
- Temperature conditions
- Definition of Ambient Temperature
- Moving or unpacking
- Air conditioner operation
- Vibration and shock specifications, and specification setup conditions
- Vibration
- Shock
- Drop of packed HDD
D. Air Quality and Dust Conditions
- Dust
- Corrosive gas
A. Temperature Range
i. Temperature conditions
Our HDDs are designed to operate within the ambient temperature range specification. However, if ventilation is not adequate,
the heat generated by the HDD itself may adversely increase its temperature. Check that each part of the HDD is within the
temperature range specification for the specific model.
If the temperature increases above the specified range, the mechanical functions of the head positioning mechanism or the
circuit element functions may be degraded. This results in degraded read-write performance and HDD reliability.
If the temperature of any part of the HDD does not stay below the specified upper limit of the temperature range, forced cooling
of the HDD is required.
It is not a problem if some part of the HDD temporarily reaches the upper limit of the specified temperature range. However,
if the part remains at the upper limit during normal operation, the life and reliability of the HDD may be adversely affected.
Long-term use of the HDD requires that the DE surface temperature be kept within the range specification for the specific
model.
ii. Definition of Ambient Temperature
Ambient temperature is defined as the temperature 3 cm from the DE surface or printed circuit board assembly surface of the HDD. An example of a DE surface temperature measurement point is shown below;
If it is difficult to measure temperature in the system, take any necessary measures, such as air conditioning, so that the DE surface temperature specifications explained above are satisfied even under the maximum allowable system temperature.
B. Condensation
A drastic change of HDD temperature can cause condensation. Condensation inside a DE causes serious problems such as adsorption
failure or a head crash.
Condensation on the HDD surface (on the DE case or printed board surface) may impair the insulation of electric circuits or
cause corrosion which can lead to a continuity error or an accumulation of dust. Be sure that this does not happen.
If you believe that condensation has occurred in the HDD, promptly contact your local distributor, reseller, or Fujitsu sales
office for check and repair of the unit.
Generally, condensation can be prevented by maintaining the following environmental conditions:
- Humidity range: 5 to 80% RH
- Temperature range: 5 to 45 degrees centigrade (ambient temperature)
- Wet-bulb temperature: 29 degrees centigrade or less
- Temperature gradient: Within 15 degrees centigrade/h
Examples of conditions likely to cause condensation and preventive measures are explained below
i. Moving or unpacking
Condensation may occur if the HDD is left in a low-temperature environment for a long time and then is moved to a high-temperature
environment. In this case, do not unpack the HDD before moving it but move it packed in its package. After carrying it to
the high-temperature environment, leave it packed until it adapts to the ambient warm temperature.
This kind of care is specifically required for a HDD left outdoors or in a non-air-conditioned warehouse or when it is moved
from an air-conditioned room during summer to a high temperature outdoors.
In general, care must be taken to prevent condensation when the temperature difference between the HDD and the ambient air
is 20 degrees centigrade or more.
The time required for the HDD to adapt to the ambient temperature depends on the temperature difference between the HDD and
the environment. Use one hour per 15 degrees centigrade as a standard for HDDs packed in Fujitsu-specified packages.
ii. Air conditioner operation
After a system is stopped for a certain period of time, the HDD may be fully cooled. A drastic increase in the ambient temperature
may cause condensation.
This is especially true in a cold area where the system and air conditioner are stopped at night or on holidays. The HDD is
fully cooled in the next morning or the morning after a holiday. In this environment, condensation is more likely to occur.
To prevent condensation in this environment, run the air conditioner so that the room temperature is raised no faster than
15 degrees centigrade per hour and the humidity is kept under the specified level (80% RH or less).
C. Vibration and Shock
i. Vibration and shock specifications, and specification setup conditions
The vibration and shock specifications of our HDDs are provided for each model. Be careful not to apply vibration and shock
greater than the specified values.
The vibration and shock specifications are defined around the frame screws on the fixture. The vibration and shock specifications
are based on data measured on a HDD mounted with screws through the specified holes on the fixture secured to a vibrating
table. Note that we do not guarantee the vibration and shock specifications if the specified screw holes are not used to attach
the HDD.
If it is anticipated that greater vibration or shock than the specified values will be applied to the HDD, call a Fujitsu
sales and support office near you for further instructions.
If vibration or shock greater than the specified values is applied to the HDD, promptly call a Fujitsu sales and support office
for check and repair.
ii. Vibration
Vibration greater than the specified value that is applied to the HDD during operation will be transmitted to the heads and
impair the positioning control system and degrade read-write performance.
An HDD mounted in a system may be adversely affected by cabinet vibration. Pay special attention to cabinet resonance. Vibration
from outside the cabinet may be amplified to a level greater than the specified value before it reaches the HDD.
iii. Shock
Be careful not to apply a shock greater than the specified value. Such shock may impair mechanisms such as the spindle, normal
positioning to be affected or damaging the disk and destroying data.
The specified clearance (2.5 mm) between the HDD and cabinet may not be provided, the HDD may not be firmly secured to the
cabinet, or the cabinet may not be rigid enough. If so, the cabinet may bump the HDD by vibration or shock and apply a shock
to the HDD greater than the specified value.
When moving an unpacked HDD, be careful not to give it a shock greater than the specified value, such as by hitting it against
a rigid surface or dropping it. When placing the HDD on a desk, first cover the desk with a rubber mat. Work on the HDD in
an area with enough service clearance. These considerations can prevent accidents.
iv. Drop of packed HDD
A HDD packed in Fujitsu-specified packing materials is not damaged when it is dropped 60 cm. However, the packing box may
break to protect the device inside
A packing box not specified by Fujitsu or even a Fujitsu-specified packing box deformed or damaged due to repeated use may
not be free of damage when dropped from the specified height. Therefore, when moving the HDD, be careful to pack and handle
it carefully to minimize shock.
D. Air Quality and Dust Conditions
i. Dust
The HDD head and disk are enclosed in the DE, which is sealed to prevent the entry of dust. The DE also has a breathing filter.
Through this filter, inside and outside air is exchanged whenever a pressure difference occurs between the inside and outside
of the DE as the spindle starts or the temperature changes.
Our HDDs are designed so that they do not adsorb dust in a general office environment. Thus, in a general office environment,
there is no need to take special measures regarding dust. The dust can cause serious problems in HDDs. Be careful in such
an environment.
ii. Corrosive gas
If the HDD is used in an environment where a corrosive gas is generated, the gas can enter the inside of the DE through the
breathing filter and chemically affect the components inside. Corrosive gasses include hydrogen sulfide, nitrogen oxide, and
oxides. Substances generated by chemical reactions float inside the DE and between the rotating disk and floating head, causing
a head to crash.
Corrosive gasses can cause serious problems in HDDs. Be careful in such an environment.
E. Safety Standards
Our HDDs conform to the following safety standards:
- UL: UL 1950
- CSA: CAN/CSA C22.2 N0950
- IEC: EN 60 950
We have not obtained certification on stand-alone HDDs for electromagnetic interference (EMI). These HDDs do conform to FCC class B when installed in cabinets.
