What if a thermometer is off by a few degrees? If that thermometer is monitoring a medical storage unit or a restaurant fridge, then a slight deviation could have severe consequences–such as spoiled vaccines, unsafe food, or inaccurate lab test results. Calibration standards are meant to prevent scenarios like this, ensuring that tools we use every day are accurate and reliable.
Learn about the essentials of calibration standards with this guide, including what they are, how they work, and how to perform calibrations. You’ll also find out about practical tips to keep your equipment in good condition–and within compliance.
What are calibration standards?
Calibration standards are reference points for making sure that measurements by tools and devices are accurate and reliable. They give a known value or set of values that serve as a benchmark.
For example, if you’re calibrating a thermometer, you might use the freezing point of water (0°C or 32°F) as a standard. If your thermometer doesn’t read that correctly, you know it’s off and will need adjustment. The same principle applies to other devices like scales, pH meters, and pressure gauges.
These standards aren’t random–they’re established by national or international organizations like the International Organization for Standardization (ISO) or the National Institute of Standards and Technology (NIST). Their role is to create uniformity so that a kilogram measured in Germany weighs the same as a kilogram measured in Japan.
What is the correct procedure for calibration?
Quality managers typically carry out the calibration of measuring instruments as part of an internal quality management system. The ISO 9001:2015 serves as a useful companion and also helps to ensure the necessary quality and safety standards are being adhered to.
Calibration usually involves the following steps:
1. Definition of the measurement process
Before starting any calibration, you’ll need to be clear about the measurement process. This means identifying exactly what you will measure (such as temperature, pressure, or voltage), then detailing the equipment, with specifics like the make, model, and serial number.
Environmental factors like temperature and humidity can have a significant effect on the accuracy of measurements, so it’s essential to either control these conditions or take them into account.
2. Creation of a model for calibration evaluation
Once you’ve defined the process, the next step is to establish a model for calibration evaluation. This acts as a framework to check if your instrument’s performance meets the standards. It covers:
- Reference standard: These should be based on national or international standards for accuracy.
- Criteria for accuracy and performance: Define what “acceptable” looks like. For example, a thermometer might be required to stay within ±0.5°C of the reference standard.
- Frequency of calibration: Determine how often you’ll need to calibrate the equipment. This can depend on how often it’s used, the critical nature of the measurements, and past data.
- Assessment methods: Outline how you’ll evaluate the equipment’s performance. Will you compare multiple data points? Will you perform repeat tests to confirm consistency?
- Decision-making process: Set guidelines for what you’ll do if an instrument fails to meet the criteria. Will you adjust, repair, or remove it from service? This way, you can be consistent in how to handle calibration failures.
By planning this thoroughly, you can turn calibration into an organized process with outcomes that are clear and measurable.
3. Performing the calibration
During the calibration, you’ll compare the measurement results from the instrument you’re testing to those from a known calibration standard.
First, make sure that the equipment you’re about to calibrate is in good working condition, and the reference standards are properly calibrated themselves.
Once everything is set, the actual calibration begins. You’ll apply a known input to the device and record its output, then compare that output to the reference standard. Let’s use a scale as an example:
- Obtain a reference weight, such as a 10 lb calibration weight that’s validated by a standards organization.
- Place the 10 lb reference weight on the scale and record the displayed measurement. The scale should read exactly 10 lbs if it is perfectly calibrated.
- Compare the scale’s measurement to the known 10 lb reference weight. If 0.05 is the tolerance range, a reading of 9.94 lbs would fall outside.
If the readings fall within the defined tolerance range, the equipment passes. But if not, you’ll need to make adjustments to the instrument. After adjustments, retest the device to confirm that it already meets the accuracy requirements.
To double-check, it’s critical to do multiple measurements. There should be no major variations between readings.
4. Documenting deviation and calibration results
Aside from the calibration itself, you’ll also need to maintain a thorough calibration record. This serves as proof of compliance with industry standards and also gives you a reliable audit trail for future reference.
Documentation should cover:
- Date of calibration and person responsible
- Details of the equipment tested (e.g., serial number, model, location)
- Reference standards used (including their calibration status)
- Measured values compared to expected standards
- Any deviations or discrepancies found
- Corrective actions taken, if applicable (such as adjustments made to the equipment)
- Final confirmation of accuracy after adjustments or re-tests
It’s critical to document deviations because these can potentially show recurring issues, such as equipment that often falls out of calibration.
Tips on how to comply with calibration standards
A calibration standard follows strict guidelines that ensure the functionality and quality of the equipment.
Regular maintenance
By carrying out regular maintenance such as calibration checks, you stay in control of the equipment in your company. In this way, you’ll reduce unnecessary risks and damages. Instead of waiting until equipment fails or shows obvious signs of inaccuracy, create a calibration schedule and stick to it.
Immediate problem reporting
A decisive step is the reporting of results that deviate from the standard. If the instrument measurements show errors, it’s important to report the deviations immediately so the responsible staff can correct them. Make the reporting process simple—whether it’s through a quick form or a digital system like in Lumiform. The key is for everyone to know who to notify and how to escalate issues if there are problems with calibration.
Comprehensive training
Your team should understand how to perform calibration checks as well as why they’re important, which builds a sense of accountability. Training should cover:
- Basics of calibration procedures
- How to recognize signs of equipment drift
- What steps to take if there are deviations
When there’s new equipment or standards change, update your team with quick refresher sessions to keep everyone on the same page.
Which devices need calibration?
It’s important to keep in mind that, depending on how you plan to use a device or tool, the needs of calibration might differ. For example, if you have a device that has multiple functions, but is only using it to measure height instead of, say, the diameter or straightness of an object, it doesn’t make sense to calibrate the device functions that you’re not going to use. That’s just a waste of time and money.
However, you should still know how, when, and at what intervals your devices will need recalibration.
Here is a list of just a few examples of items that need to be regularly recalibrated to maintain device integrity:
- Medical equipment
- Lab equipment
- Centrifuges
- Construction tools
- Computers
- Touch screens
- Gauges
- Lasers
- GPS
- Vehicles
As you can see from the above examples, failure to recalibrate any of these devices corresponding to the manufacturer’s recommendations could compromise the quality and safety of the product. Depending on what you’re using the product for, this could have varying degrees of severity.
For example, what if a laser being used in surgery was off by a few millimeters? That may not seem like a lot, but in medical terminology, you might as well be talking about a matter of life and death. A major artery might be millimeters away from the operation site. What then?
Calibration might seem like a dull, time-consuming topic easy to cut corners and forget about, but when it really comes down to it, your business could hinge on your ability to recalibrate your tools correctly.
Using digital tools to manage calibration standards
With Lumiform’s digital calibration forms, you can easily carry out regular checks via tablet or smartphone – online or offline. Using the desktop software, you can record measurements and then evaluate the collected data. For example, you can directly identify information about measuring device malfunctions and solve incidents up to four times faster.
- The AI form builder from Lumiform helps you to convert any individual paper list into a digital checklist with little effort.
- Using the super intuitive app, you and your teammates can conduct checks in the field with ease.
- Comprehensive analyses help you to identify inefficient areas in your company more quickly and, thus, continuously improve your auditing and inspection processes.
- Save time by making it easier to analyze all the data from the calibration log and quickly identify areas that need your attention.
Try Lumiform for free today to experience the ease of streamlining your calibration processes!