Standard Atmospheres to Pounds Per Square Foot (atm to psf)
1 standard atmosphere equals 2,116.216624 pounds per square foot (rounded).
How to convert standard atmospheres to pounds per square foot
To convert standard atmospheres to pounds per square foot, multiply the number of standard atmospheres by 2,116.216624. The factor is rounded to 10 significant digits. To go the other way, multiply pounds per square foot by 0.000472541416 (rounded).
pounds per square foot = standard atmospheres × 2,116.216624
Example: 10 standard atmospheres = 21,162.16624 pounds per square foot.
About these units
Standard Atmosphere (atm)
Exactly 101,325 pascals, the average pressure of the atmosphere at sea level.
A column of mercury about 76 cm tall was Torricelli's measure of the air, and the standard atmosphere began as exactly that: the pressure of 760 mm of mercury at 0 degrees Celsius under standard gravity. It was used as a reference for physical and chemical properties, and the Celsius scale set 100 degrees as the boiling point of water at that pressure.
In 1954 the 10th CGPM confirmed the standard atmosphere as exactly 1,013,250 dynes per square centimeter, which is 101,325 pascals, a definition that no longer depends on the properties of any substance.
In practice one atmosphere is about 1.01325 bar, 760 mmHg, 14.696 psi or 29.92 inHg, and roughly the pressure of 10.33 meters of water. Chemistry splits on it: until 1982 standard temperature and pressure used 1 atm, but that year IUPAC recommended a standard pressure of exactly 100 kPa instead.
1 standard atmosphere = 101,325 pascals (exactly).
Sources: Wikipedia: Standard atmosphere (unit); Wikipedia: Atmospheric pressure; Wikipedia: Evangelista Torricelli
Pound Per Square Foot (psf)
About 47.88 pascals. Used in US structural engineering for distributed loads.
A square foot is 144 square inches, so one pound per square foot is one 144th of a psi, which comes to about 47.88 Pa; NIST gives 47.88026. The number is easy to picture: spread one pound-force evenly over a floor tile a foot across and that is the pressure, tiny compared with the 101,325 Pa of one standard atmosphere.
Building codes in the United States commonly state loads on floors and roofs this way, and snow and wind pressures are tabulated in the same unit. Metric countries use kilopascals or newtons per square metre instead, and 1 kPa is about 20.9 psf. Multiplying a psf figure by 144 gives psi, and by 47.88 gives pascals, so a 40 psf floor load is about 1.9 kPa.
1 pound per square foot = 47.88025898 pascals (approximately).
Sources: NIST SP 811, Appendix B.8; Wikipedia: Pounds per square inch
Related conversions
- Pounds per square foot to standard atmospheres (reverse)
- Standard atmospheres to pascals
- Standard atmospheres to kilopascals
- Standard atmospheres to bars
- Standard atmospheres to PSI
- Standard atmospheres to hectopascals
- Standard atmospheres to megapascals
- Standard atmospheres to millibars
- Standard atmospheres to torr
- Standard atmospheres to millimeters of mercury
- Standard atmospheres to inches of mercury
- Standard atmospheres to gigapascals
- Standard atmospheres to kilopounds per square inch
- Pascals to pounds per square foot
- Kilopascals to pounds per square foot
- Bars to pounds per square foot
- PSI to pounds per square foot
See all pressure units.