Technical Atmosphere (at)

CGS & old metricHistorical unit (no longer in standard use)

Exactly 98,066.5 pascals: one kilogram-force per square centimeter. Still seen on gauges in older equipment.

1 technical atmosphere = 98,066.5 pascals (exactly).

About the technical atmosphere

Pressure given as kilograms-force per square centimeter is the technical atmosphere, symbol at. It is fixed by arithmetic rather than by any air measurement: one kilogram-force is 9.80665 newtons and a square centimeter is one ten-thousandth of a square meter, so the unit is exactly 98,066.5 pascals, or 98.0665 kilopascals. Shop-floor shorthand includes kg/cm2, kp/cm2 and, in some older publications, ksc.

It is close to, but not the same as, other familiar pressures. It is about 0.981 bar, roughly 2 percent below a bar, and about 0.9678 of a standard atmosphere. In pounds per square inch it comes to about 14.22. The unit is deprecated and outside SI, yet it lingers because older pressure gauges and equipment, including Soviet-made instruments, are still in service with dials marked in kgf/cm2. NIST conversion tables list it with an exact factor to the pascal.

Sources: Wikipedia: Technical atmosphere; NIST SP 811, Appendix B.8 conversion factors; Wikipedia: Kilogram-force

Technical Atmosphere conversion chart

1 technical atmosphere expressed in every other pressure unit:

More CGS & old metric units

• barye (pressure)
• erg (energy)
• kilogram-force meter (energy)
• erg per second (power)
• kilogram-force (force)
• gram-force (force)
• dyne (force)
• tonne-force (force)

All CGS & old metric units

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