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PSIG na PSIA

PSIG na PSIA

Użyj lokalnego ciśnienia atmosferycznego dla precyzyjnych wyników.

PSIG na PSIA

Użyj lokalnego ciśnienia atmosferycznego dla precyzyjnych wyników.

Precyzja: 3

Ciśnienie manometryczne względem powietrza otoczenia.

Ciśnienie absolutne odniesione do idealnej próżni.

Wskazówka: PSIA = PSIG + P_atm.

Wzór: PSIA = PSIG + P_atm

How to Convert PSIG to PSIA

Converting PSIG (gauge pressure) to PSIA (absolute pressure) is a straightforward process that involves adding the local atmospheric pressure to your gauge reading. Here's a step-by-step guide:

1
Measure PSIG Read your gauge
2
Add P_atm ≈14.7 psi at sea level
3
Get PSIA Result in absolute

Example Conversion

If your gauge reads 50 PSIG at sea level:

PSIA = 50 + 14.7 = 64.7 PSIA

Important Note

Always use your local atmospheric pressure for accurate results, especially at high altitudes.

PSIG to PSIA Formula

The formulas for converting between PSIG and PSIA are simple and rely on the atmospheric pressure value:

PSIG → PSIA
PSIA = PSIG + Patm
Add atmospheric pressure to gauge pressure
PSIA → PSIG
PSIG = PSIA − Patm
Subtract atmospheric pressure from absolute

Where Patm ≈ 14.6959 psi at sea level (standard atmospheric pressure). This value decreases at higher altitudes.

PSIG to PSIA Conversion Chart

Quick reference table for common PSIG to PSIA conversions at sea level (Patm = 14.7 psi):

PSIG PSIA Common Use
0 14.7 Atmospheric pressure
10 24.7 Low pressure systems
30 44.7 Typical tire pressure
50 64.7 Compressed air tools
100 114.7 Industrial applications
125 139.7 Steam systems
150 164.7 High pressure systems
-14.7 0 Perfect vacuum

Note: These values assume standard sea-level atmospheric pressure. Adjust for local conditions when precision is required.

PSIG and PSIA Difference

Understanding the difference between PSIG and PSIA is crucial for accurate pressure measurements in engineering and scientific applications.

PSIG (Gauge Pressure)

  • Referenced to local atmospheric pressure
  • Zero point = ambient air pressure
  • Can be negative (vacuum)
  • Used in: tire pressure, air tools, general industry

PSIA (Absolute Pressure)

  • Referenced to perfect vacuum
  • Zero point = complete absence of pressure
  • Always positive (cannot be below zero)
  • Used in: thermodynamics, altitude calculations, scientific work
PRESSURE SCALE REFERENCE
0 PSIA
Vacuum
14.7 PSIA
Sea Level
= 0 PSIG
Higher
Positive PSIG

PSIG to PSIA Equation

The mathematical relationship between PSIG and PSIA is expressed through a simple linear equation:

Pabs = Pgauge + Patm
Pabs = Absolute pressure (PSIA)
Pgauge = Gauge pressure (PSIG)
Patm = Atmospheric pressure
Sea Level
Patm ≈ 14.696 psi
Denver (5,280 ft)
Patm ≈ 12.2 psi
Mount Everest
Patm ≈ 4.4 psi

Is PSI PSIA or PSIG?

"PSI" (pounds per square inch) is the unit of pressure measurement, but it doesn't specify whether it's absolute or gauge. Here's how to determine which type is meant:

G
PSIG
Gauge reading
Shown on most gauges
A
PSIA
Absolute reading
Scientific & engineering
?
PSI
Context dependent
Usually means PSIG

Rule of Thumb

When "PSI" is written without a suffix, it usually means PSIG in practical applications. Always confirm the reference point when precision matters.

PSIG vs PSIA vs PSID

These three pressure measurement types serve different purposes. Here's a comprehensive comparison:

Aspect PSIG PSIA PSID
Full Name Pounds per Square Inch Gauge Pounds per Square Inch Absolute Pounds per Square Inch Differential
Reference Point Local atmosphere Perfect vacuum Another pressure point
Can Be Negative? Yes (vacuum) No Yes
Zero Meaning Atmospheric pressure Complete vacuum No pressure difference
Common Uses Tires, air tools, HVAC Thermodynamics, altitude Filters, flow meters

What is PSID?

PSID measures the pressure difference between two points, such as across a filter or valve. It doesn't reference atmosphere or vacuum—only the delta between two pressures.

PSIG vs PSIA vs PSI

Understanding the relationship between these terms is essential for correctly interpreting pressure measurements:

PSI (Unit of Measurement) PSIG Gauge PSIA Absolute
PSI

The base unit—pounds per square inch. Describes force per area without specifying reference.

PSIG

PSI measured relative to atmospheric pressure. Most common for everyday use.

PSIA

PSI measured from true zero (vacuum). Required for scientific calculations.

PSIA vs PSIG Gauge

Physical pressure gauges can be designed to measure either PSIA or PSIG, and the type you use depends on your application:

0 PSIG

PSIG Gauge

  • ✓ Reads 0 at atmospheric pressure
  • ✓ Open to atmosphere on one side of diaphragm
  • ✓ Most common type for industrial use
  • ✓ May show negative values for vacuum
0 PSIA

PSIA Gauge

  • ✓ Reads ≈14.7 at atmospheric pressure
  • ✓ Sealed vacuum reference chamber
  • ✓ Used for precise scientific measurements
  • ✓ Always shows positive values

How to Identify Your Gauge Type

Check the gauge face for markings: "G" or "PSIG" indicates gauge pressure, "A" or "PSIA" indicates absolute. If unmarked, assume PSIG—it's the default for most industrial gauges.

Najczęściej zadawane pytania

Czy 14.7 PSIA jest równe 0 PSIG?
Tak—w standardowych warunkach na poziomie morza układ przy ciśnieniu atmosferycznym pokazuje ≈14.7 PSIA i 0 PSIG.
Czy PSIA i PSIG to to samo?
Nie. PSIA to ciśnienie absolutne (odniesione do próżni). PSIG to ciśnienie manometryczne (odniesione do otoczenia). Używaj PSIA w termodynamice i gdy wysokość ma znaczenie.
Co oznacza 14.7 PSIA?
To ciśnienie absolutne na poziomie morza w warunkach standardowych—powietrze naciska z siłą 14.7 funta na cal kwadratowy ponad próżnią.
Czy 14.7 PSIA to ciśnienie atmosferyczne?
To powszechnie używana standardowa wartość odniesienia dla poziomu morza. Rzeczywiste ciśnienie atmosferyczne zmienia się wraz z pogodą i wysokością.