IBM System/38 Instruction Manual page 41

You may need to control the heat and humidity by
means of heating, cooling, and humidity-controlling
equipment to maintain an acceptable and stable
environment.
Electrostatic Discharge: With low humidity levels, static
charges generated by such things as movement of
people, carts, furniture, and paper are more readily
stored in certain types of floor construction, floor
coverings, and furniture. These charges may be high
enough that, if discharged by contact with another
person or object, will create a static shock and can
cause intermittent interference on data processing or
other electronic equipment. To minimize electrostatic
discharge, do the following:
• Avoid high-resistance floor surface material. Floor
surface resistance measured between the floor
surface and the building (or applicable ground
reference) should be greater than 150 000 ohms and
less than 2 x 10
10
ohms. The measuring method is
specified in NFPAl 56A, Chapter 462.
• Avoid carpeting that does not have antistatic
properties.
• Avoid plastic seat coverings.
• Avoid low humidity levels.
Temperature- and Humidity-Associated Problems in Tape,
Diskette, and Paper Document Storage Areas: Keep
storage areas at the same relative humidity and
temperature as the data processing room. There are
several good reasons for this:
• An extreme humidity difference between the two
areas might alter the size of paper documents when
they are moved into the working area.
• A rapid change in environment can result in paper
warpage, the most frequent cause of feeding and
stacking problems.
Using cold tapes or diskettes in a warm room can
cause condensation on the tapes or diskettes.
1
National Fire Protection Association, 470 Atlantic Avenue,
Boston, Massachusetts 02210.
6-2
If working and storage areas cannot be kept at the
same relative humidity and temperature, allow enough
time for tapes and paper to achieve a temperature and
moisture balance with that of the data processing room
before using them.
For detailed information about handling, storing, and
shipping tapes and diskettes, refer to:
• Tape Requirements for IBM One-Half Inch Tape Units
at 556, 800, 1600, and 6250 BPI, GA32-0006
• The IBM Diskette General Information Manual,
GA21-9182
Desired Operating Environment
Operating environment temperatures and humidity as
determined in Step 3, on page 6-4 are the limits at
which the system will function. However, the system is
not intended to operate satisfactorily for a long period of
time at these limits. The desired operating environment
is the mid-point of the specified limits, for example,
70-75°F dry bulb and 40-50% relative humidity. Air
conditioning equipment. required because of extremes in
temperature and/or humidity, should be designed to
maintain the specified limits. This desired range
provides time to react if the temperature and/or
humidity leaves the preferred range and begins to
approach the limits. The operator can use this time to
take corrective action.