10
15
20
25
30
35
0.000
0.010
0.020
0.030
0.040
PSYCHROMETRIC CHART
Dry Bulb Temperature (°C)
Recommended
Allowable
H
um
id
it
y
R
at
io
(
kg
w
/k
g
da
)
RH = 20
%
RH
= 50
%
RH
=
80
%
22 ° C max dew point
for TS1160 and LTO9
drives
26 ° C m
ax wet b
ulb
Notes:
The chart is shown in SI (metric) units and a barometric pressure of 101.325 kPa (sea level).
The recommended operating environment specifies a long-term operating environment that can result in the greatest reliability and energy efficiency.
The allowable operating environment represents where the equipment has been tested to verify functionality. Due to the stresses that operating in the
allowable envelope can place on the equipment, these envelopes should be used for short-term operation, not continuous operation (for example, in
the case of a cooling failure).
Table 2. Gas and particulate exposure
Contaminate
Requirement
Gaseous
contamination
Severity level G1 as per ANSI/ISA 71.04-1985,
1
which states that the reactivity rate of copper coupons shall be less than 300 Angstroms per month
(Å/month, ≈ 0.0039 µg/cm² - hour weight gain).
2
In addition, the reactivity rate of silver coupons shall be less than 300 Å/month (≈ 0.0035 µg/cm² -
hour weight gain).
3
The reactive monitoring of gaseous corrosivity should be conducted approximately 5 cm (2 inches) in front of the rack on the air
inlet side at one-quarter and three-quarter frame height off the floor or where the air velocity is much higher.
Particulate
contamination
Data centers must meet the cleanliness level of ISO 14644-1 class 8. For data centers without airside economizer, the ISO 14644-1 class 8
cleanliness might be met simply by the choice of the following filtration:
The room air might be continuously filtered with MERV 8 filters.
Air entering a data center might be filtered with MERV 11 or preferably MERV 13 filters.
For data centers with airside economizers, the choice of filters to achieve ISO class 8 cleanliness depends on the specific conditions present at that
data center.
The deliquescent relative humidity of the particulate contamination should be more than 60% RH.
4
Data centers must be free of zinc whiskers.
5
8
IBM TS22xx - TS2290, TS2280, and TS2270
