Frequently asked questions

Q: What is the single biggest mistake people make when calculating the Uncertainty Budget for pressure calibration?

A: The most frequent and costly mistake is failing to correctly account for the Stability and Drift of the Standard (e.g., the Deadweight Tester or Pressure Calibrator) between scheduled calibrations. Ignoring this term often leads to an underestimated budget, putting your whole scope of accreditation at risk of non-compliance with ISO 17025.

Need an urgent review of your uncertainty budget? Email us now at info@addit-metrology.com for a confidential consultation.

Q: How can Add It Metrology help me fix a fundamentally flawed uncertainty budget?

A: Our Advanced Pressure Metrology & Uncertainty Workshop is specifically designed to address and correct these foundational errors. We provide hands-on training to accurately identify all error sources and develop compliant, defensible uncertainty budgets that meet strict regulatory body standards.

Ready for a compliant budget? Call +44 7498 956 496 to schedule your team's advanced training.

Q: What criteria must be met to ensure I am using the correct Standard for a pressure calibration?

A: The primary rule (often called the Test Uncertainty Ratio or TUR) is that the calibration standard must be at least four times more accurate than the instrument under test (IUT). Using a standard that is only twice as accurate is a common mistake that invalidates the calibration and is a frequent point of failure in an ISO 17025 audit.

Are you using the right standards? Our Consultancy Services can conduct a technical review of your entire lab's equipment register and procedures to eliminate this risk. Email us for details.

Q: We rely on Deadweight Testers (DWTs). What is the biggest mistake related to using a DWT?

A: The biggest mistake is neglecting the mandatory environmental corrections, specifically for gravity, temperature, and air buoyancy. If your DWT procedure does not include calculating the Effective Mass based on your current location’s gravity, your reference pressure is wrong, and all subsequent calibrations are incorrect.

Add It Metrology specialises in DWT operational training. Ensure your team masters these critical calculations. Ring +44 7498 956 496 for course availability worldwide.

Q: How does proper cleaning technique prevent incorrect pressure readings?

A: Contamination (oil, dust, moisture) inside pressure lines or instruments is a major source of erratic and incorrect readings, especially in low-pressure applications. Proper use of isolating fluids and cleaning solvents, as covered in our training, is critical to maintaining the precision and reliability of your standards and test equipment..

We detail essential preventative maintenance in our training. Download our free guide on system maintenance by submitting your email.

Q: What are the immediate signs that a pressure gauge is providing a significantly incorrect reading?

A: Beyond outright failure, look for a non-linear error trend (e.g., accurate at 50% but highly inaccurate at 10% and 90% of span), or an unexpectedly large Hysteresis error. A fluctuating reading when the pressure is stable is also a key indicator of potential system contamination or component wear that must be investigated immediately.

Think your results are wrong? Our Practical Calibration Workshop teaches technicians precise diagnostic techniques. Contact us to book an on-site intervention.