Modern pressure gauges are very accurate and precise. However, drifting in pressure readings occur due to their continuous use. For this reason, pressure gauges must be calibrated regularly. As critical industrial equipment, it is recommended to calibrate a pressure gauge before installation, during shutdowns, and at regular intervals to ensure regulatory standards are met. At Biotechnical Services, Inc., we have a team of experienced experts for the best pressure gauge calibration in San Diego.

What is a Pressure Gauge?

A pressure gauge is a device for measuring the intensity of steam, gas, water, or any fluid in a system. It detects pressure leaks by indicating pressure changes that might affect the performance of pressure operated machine. There are two broad types of pressure gauges, i.e.:

Analog pressure indicators: An analog pressure gauge has a pressure scale and a pointer needle to indicate pressure levels. An analog pressure gauge is made of a capsule, diaphragm and Bourdon tube. Its mechanical structure shifts the pointer across the scale reading as the pressure reading increases or decreases.

Digital pressure gauges: A digital pressure gauge has a numeric pressure indicator with the same function as the analog pointer. 

Mechanical pressure in a system causes a pressure gauge to get damaged or indicate wrong readings. When this happens, you need an accredited lab for the calibration of your pressure gauge. If you live in San Diego or its neighboring areas, contact Biotechnical Services, Inc. for your pressure gauge calibration in San Diego. Our expert technicians will swing into action and repair your damaged pressure gauge movements, scales, pointers, and windows.

Things to Consider for Pressure Gauge Calibration

Gauge Accuracy

Pressure gauges are manufactured in different accuracy classes. Accuracy classes are specified according to the percentage range of pressure gauge standards. A gauge with 1% accuracy means has a scale range of zero to a hundred with an accuracy of plus or minus one. The pressure gauge’s accuracy class helps determine both the acceptable accuracy level and the effects on the calibration procedure.

Pressure Media

The common media for pressure gauge calibration are liquid and gas.  Regular air and nitrogen are most used as gases for calibration. When it comes to liquid, oil or water is used. The media used in calibration mainly depends on what the gauge is usually connected to; either gas or liquid. Another factor to consider when choosing pressure media is the pressure range. Low-pressure ranges are the best for gases or air, while high-pressure ranges favor liquid media.


When selecting a media for calibration, the pressure media used in a particular gauge should be considered. Some media could cause problems when the gauge is fixed back to its process. Other process media could also harm the calibration equipment. Some dirt in a pressure gauge can damage calibrating equipment.  When calibrating a gas-operated gauge, it is best to use a moisture trap or a dirt-trap. In contrast, on a liquid-operated gauge, it is recommended to clean the gauge before calibration.

Height Difference

When the pressure gauge and the calibrating equipment have a height difference, the hydrostatic pressure often causes errors. The magnitude of the pressure error mostly depends on the height difference and the density of the liquid used. If the heights of both the calibrator and the gauge cannot be the same, the difference should be considered when calibrating the gauge.

Leak Test

If there are leaks in the piping system during the calibration, unpredicted errors are likely to occur. Before calibration is done, it is recommended to perform a leak test to eliminate potential errors. A pipe leak test is done by pressurizing the system and monitoring the pressure drop rate in the reading. When the pressure drops significantly, it means there is a pipe leakage.

Adiabatic Effect

When gas pressure is increased rapidly, the gas temperature will rise, causing the gas to expand, leading to a larger volume and pressure. However, when the temperature in the enclosed system drops, both the volume and gas pressure will drop significantly. It might seem like a pipe leakage in the system, but basically, it is the adiabatic effect caused by the drastic change of the gas temperature.

Torque Force

Some gauges are sensitive to the torque force. Excessive force when connecting the gauge to a pressure connector can cause a damaging effect on the gauge. It is recommended to follow the manufacturer’s manual and use appropriate adapters, seals, and tools.

Calibration and Mounting Positions

Since the gauges are mechanical equipment, the mounting position will affect the pressure reading. When calibrating the gauge, it is recommended to place it at the exact position using the industrial process. It is important to follow the manufacturer’s instructions for mounting and calibration positions.

Source of Generating Pressure

There are different methods of generating pressure for the pressure gauge calibration. These are; a deadweight tester, pressure regulator, and hand pump. 

A combination of a hand pump and a calibrator is mostly used for gauge calibration.

Pressurizing a Gauge

It is important to exercise a pressure gauge before calibration to test the possible mechanical errors. Pressure is applied to the maximum several times when exercising a gauge, and the gauge is studied.

Expert's Opinion on The Best Time to Calibrate a Pressure Gauge

As the experts in pressure gauge calibration in San Diego, clients have asked us about the needed frequency of gauge calibration. With the historical trend in pressure gauge calibration at Biotechnical Services, Inc., we have expansive advice on the best time to calibrate pressure gauges.

Here are considerations for pressure gauge calibration time:

Process Tolerance and Gauge Accuracy

Each pressure gauge transmitter in the system has its specified accuracy and a long-term stability guarantee from the manufacturer. However, each process in the system has a different tolerance requirement. It is important to consider the tolerance of a particular system for accuracy.

Measurement Criticality

When determining the calibration period intervals, it is best to consider the criticality of the measurement. The critical process requires frequent calibration while keeping the acceptance tolerance very tight.  The non-critical process may require that the pressure gauges be calibrated less often, especially where the process requires less accuracy.

Reference Standards

Depending on the accuracy required in the system, the pressure gauge precision should be kept as close as possible to the reference standard requirements.

Manufacturer’s recommendation

Almost all industrial instruments have the manufacturer’s recommendation period for calibration. When starting the first calibration, it is better to follow the stability recommendation of the manufacturer. In this regard, the intervals of the calibration can be adjusted with time.

Stability History

It is an important factor to have the calibration results before and after the recalibration. The adjustment shows the drift in the pressure gauge equipment and can be used to assess the stability of the equipment over time. At Biotechnical Services, Inc., our customers get pressure gauge calibration in San Diego and the calibration certificate indicating the level of adjustment and the stability of the pressure gauges.

Regulatory Requirements

Certain industrial measurements follow some regulations and standards set by the regulatory authorities. When this is the case, clients have to follow the acceptable interval of the calibration period.


Having been a long-time integral player in lab equipment calibration, at Biotechnical Services, Inc., we ensure professional and high-quality services in pressure gauge calibration in San Diego, San Francisco, Los Angeles as well as the majority of California. Contact us today to get the best pressure gauge calibration in San Diego and its neighboring areas.  We provide fast and precise gauge calibration. Our accurate lab calibrators ensure premium services for your devices.