BS 7404-2.1(1991) : 1991

Committees responsible
Foreword
Specification
1. Scope
2. Object
3. Temperature, humidity and barometric pressure
     classification of locations
3.1 General
3.2 Air conditioned locations (Class A)
3.3 Heated and/or cooled enclosed locations (Class B)
3.4 Sheltered locations (Class C)
3.5 Outdoor locations (Class D)
3.6 Summary of location classes
3.7 Barometric pressure
4. Mechanical influences
4.1 General
4.2 Vibration
4.3 Mechanical shock
4.4 Seismic effects (earthquakes)
5. Power supply
5.1 General
5.2 A.C. supply
5.3 D.C. supply
5.4 Supply interruption
5.5 Voltage withstand
Appendix
NA. Deletions from and IEC text amended by Common
     modifications to IEC Publication 870-2-1 (1987)
     (informative)
Tables
I. Air temperature and humidity classes for air
       conditioned locations
II. Air temperature and humidity classes for enclosed
       locations
III. Air temperature and humidity classes for
       sheltered locations
IV. Air temperature and humidity classes for outdoor
       locations
V. Summary of location classes
VI. Location classes of barometric pressure
VII. Low frequency vibration classes
VIII. High frequency vibration classes
IX. Vibrational severity classes
X. Vibration time classes
XI. Mechanical shock classes showing preferred
       combinations of a and t
XII. Shock acceleration values
XIII. Free fall height classes
XIV. Shock repetition classes
XV. Intensity classes of earthquakes
XVI. Phenomena of earthquakes related to the scales of
       Richter and Mercalli
XVII. Untitled
XVIII. A.C. voltage tolerance classes
XIX. Frequency tolerance classes
XX. Harmonic content level classes
XXI. Untitled
XXII. D.C. voltage tolerance classes
XXIII. Earthing condition classes
XXIV. Ripple classes
XXV. Interruption time classes
XXVI. Withstand voltage classes
Figures
1. Humidity versus temperature for air conditioned
     locations
2. Humidity versus temperature for enclosed locations
3. Humidity versus temperature for sheltered locations
4. Peak displacement (amplitude) and velocity with
     low frequency vibrations
5. Peak displacement (amplitude) and velocity with
     high frequency vibrations

Applies to telecontrol equipment and systems with coded bit serial data transmission for monitoring and control of geographically widespread processes. Covers object, temperature, humidity and barometric pressure classification of locations, general, air conditioned locations, heated and/or cooled enclosed locations, sheltered locations, outdoor locations, summary of location classes, barometric pressure, mechanical influences, vibration, mechanical shock, seismic effects, power supply, supply interruption and voltage withstand.