Technical Atmospheres to PSI (at to psi)

1 technical atmosphere equals 14.22334331 pounds per square inch (rounded).

1 technical atmosphere = 14.22334331 pounds per square inch

How to convert technical atmospheres to pounds per square inch

To convert technical atmospheres to pounds per square inch, multiply the number of technical atmospheres by 14.22334331. The factor is rounded to 10 significant digits. To go the other way, multiply pounds per square inch by 0.07030695796 (rounded).

pounds per square inch = technical atmospheres × 14.22334331

Example: 10 technical atmospheres = 142.2334331 pounds per square inch.

About these units

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.

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.

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

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

Pound Per Square Inch (psi)

US & ImperialCurrent unit

About 6,894.757 pascals. The common unit for tire pressure, hydraulics and gas pipelines in the US.

Unlike most pressure units, psi has no namesake: it simply spells out its own definition, one pound-force acting on one square inch, and it is based on avoirdupois units. Used mainly in the United States, it is about 6.895 kilopascals.

The letters after the unit matter. Psia is measured against a vacuum, while psig is measured against the surrounding air, so at sea level, where the atmosphere is about 14.7 psi, you add that amount to a gauge reading to get an absolute one. A bicycle tire at 65 psig is therefore at 79.7 psia, and the label psid means a difference between two pressures rather than a reference to ambient air.

Typical automobile tires are listed at about 32 psig, and road racing bicycle tires at about 120 psig. One standard atmosphere is 14.696 psi, which gives a feel for how many multiples of sea-level air those tire pressures represent.

1 pound per square inch = 6,894.757293 pascals (approximately).

Sources: Wikipedia: Pounds per square inch; Wikipedia: Standard atmosphere (unit)

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