Today’s pressure gauges are remarkably robust and accurate, but they do lose accuracy over time. Regular calibration of pressure gauges is the best way to ensure that readings are reliable.
Different applications call for different levels of pressure gauge accuracy, and the accuracy classes range from Grade B (±3/2/3% of span) up to the ±0.05% accuracy of digital pressure gauges. To ensure that pressure measuring instruments maintain their accuracy specifications, they require regular calibration. Simple recalibrations can be done onsite using a precision digital gauge, like the CPG1500, as a reference standard. An accredited lab can calibrate and certify both mechanical and digital gauges.
When to Calibrate a Pressure Gauge
Did you know that calibrations have a shelf life? Even when the pressure gauge is not in use, it does not stay calibrated indefinitely. And of course, mechanical wear causes gauges to drift over time.
Most pressure gauges are calibrated before they leave the manufacturing facility and won’t require recalibrating before installation, if the instruments are stored properly before being put into service. For best performance, gauges should be calibrated at regular intervals. How often depends on the application and industry. Here are some recommendations and best practices for when to calibrate an electrical or mechanical pressure measuring instrument:
- Before installation, especially if the instrument has been in storage for a while or was stored improperly (for example, in high heat)
- Once a year for most gauges after installation, such as during annual ISO audits
- Every three to six months for gauges used in pharmaceutical, biotechnology, and medical device applications. A more-frequent calibration interval assures quality control and avoids expensive errors, such as having to discard an entire production batch or paying a large fine as a result of inaccurate pressure measurements.
- During planned shutdowns for preventative maintenance
- Every five years for pressure balances, which are common pressure reference instruments
Most process plants swap out pressure gauges and other instruments based on their calibration cycle or during quarterly or semi-annual shutdowns. The spare gauges are verified onsite just before they are scheduled to be installed, then the removed gauges are sent to a calibration lab so that they will be ready for the next cycle. Setting up a regular calibration cycle minimizes the chances of inaccurate pressure readings. Doing so also improves monitoring and oversight of your processes.
How to Calibrate Industrial Pressure Gauges
For those who wish to handle their own calibration, WIKA offers a complete portfolio of reference instruments and calibration equipment for in-house labs and field use. These instruments include digital pressure gauges, pressure balances, test pumps and other portable pressure generators, hand-held pressure calibrators, and the CPG2500 digital pressure measuring indicator. Our calibration software simplifies and automates the calibration of up to 16 test items. WIKA-Cal then generates the necessary calibration certificates and logger protocols.
WIKA’s Calibration Lab for Pressure Instruments
WIKA’s calibration lab is accredited to ISO/IEC 17025, the worldwide standard for testing and calibration laboratories. In addition to calibrating pressure instruments, our experienced technicians can repair or refit damaged gauges, such as replacing the gauge movement, window, pointer, and more. Then they will make the necessary adjustments to bring your gauges back into published accuracy specifications. After servicing, all instruments are recalibrated before being shipped back to the customer. In most cases, the turnaround time is five or fewer business days.
For more information about our calibration instruments or full-service calibration lab, contact WIKA USA.