What is the full form of PSI?

What is PSI?

PSI stands for Pound per Square Inch. PSI is a unit that is used to measure one pound of pressure which is applied on an area of one square inch. If the pressure of gases is measured, it is called pneumatic pressure and if the pressure of liquid is measured, it is called hydraulic pressure. Another aspect for which PSI is used is to measure resistance to pulling forces. In the case of pneumatic and hydraulic pressure, PSI is used to take into account the pressure that a gas or a liquid puts on the vessel.

1 PSI =

• 0.068046 atmospheres

• 0.0689476 Bar

• 6894.76 Pascals

• 51.7149 Torr

• 2.03602 inHg

• 27.7076 inches of water column

How is PSI used?

Usually, PSI is used to measure the pressure of a tire. The tensile strength of different materials is also measured and the pressure is measured in KPSI. If the elastic modulus is measured, MPSI is used. Here KPSI is kilo PSI and MPSI is mega PSI. Gauges are used to measure the pressure of all types of vehicles. They are also used for the pressure measurement of pneumatic and hydraulic machines.

Pascal

Usually, Pascal is used as a unit of pressure. When a pressure or force is applied to an area, it is measured in pascal. The formula for measuring pressure is given below −

P = F ÷ A 

Here,

• P is pressure

• F is force

• A is area

If we have to convert it into pascal the formula will be

$$\mathrm{Pa\:=\:N\:\div\:M^{2}}$$

Here,

Pa is Pascal

N is Newton

M² is square meter

As per these formulas, it can be concluded that pressure and surface are inversely proportional to each other.

Types of PSI

PSI is of three types and they are mentioned below −

Psia

If the pressure is measured on the basis of vacuum, it is called absolute pressure and measured in Psia.

Psig

When pressure is measured on the basis of atmospheric pressure, it is called gauge pressure and measured in Psig.

Psid

When the pressure is measured on the basis of the difference between two points, it is called differential pressure and is measured in Psid.

Difference between BAR and PSI

There are many differences between Bar and Psi and some of them can be found in the table below −

PSI	BAR
PSI is a unit used to measure one unit of pressure that is applied on 1 square meter	Pascal is used to measure the pressure applied at right angles to a volume of a surface
Used to measure the pressure of a tire	Used to measure gas and liquid pressure
It is an imperial unit	It is a metric unit
At sea level, the atmospheric pressure is 14. psi	At sea level, the atmospheric pressure is 1 bar
1 psi = 0.069 bar	1 bar = 14.51 psi
Greater unit	Smaller unit
Cannot be converted into millibars and kilopascals	Can be converted into millibars and kilopascals

Conclusion

PSI is a unit that is used to measure pressure. The full form of PSI is Pound per Square Inch. It is usually used to measure the pressure of a tire.

FAQs

FAQ 1: What is the full form of PSI

Ans: PSI can be expanded as Pound per Square Inch.

FAQ 2: What is PSI used for?

Ans: PSI is used for measuring one pound of pressure exerted on 1 square meter area.

FAQ 3: What is Bar?

Ans: Bar is called barometer pressure.

FAQ 4: Can we convert PSI into Bar?

Ans: Yes! PSI can be converted into bar. 1 Bar = 14.51 PSI

FAQ 5: Why PSI is used?

Ans: PSI is used to measure the pressure of a tire.