Learning how to calibrate lab equipment is crucial, as uncalibrated instruments can compromise the accuracy and validity of your research. Furthermore, lab calibration is crucial for maintenance, and neglecting it may put all lab employees at risk of injury or work accidents.

For this article, we’ve consulted our experts to develop a guide on how to calibrate lab equipment and ensure it adheres to national and global standards.

Read on for practical steps and tips.

What is Calibration?

Calibration is an essential part of lab equipment maintenance that involves checking and adjusting instruments’ settings to ensure precise readings. This is done by comparing the current results to a known standard and fine-tuning the instruments accordingly.

If a lab instrument isn’t calibrated regularly, its readings may be incorrect and affect the performance of the laboratory as a whole.

For instance, an uncalibrated microscope may show a distorted image, leading to misinterpretations or inaccurate measurements. This is particularly dangerous in clinical settings, where a wrong diagnosis can have severe consequences on patients’ well-being.

The Importance of Calibrating Lab Equipment

The importance of calibrating lab equipment lies in prolonging its lifespan, improving the accuracy of results, and reducing the risk of potential hazards. Overall, calibrated lab equipment is safer, more precise, and better suited for research and experimentation.

Below, we will explore the benefits of lab equipment calibration in more detail.

#1. Prolonging Lab Equipment Lifespan

Regular calibration directly impacts lab equipment’s lifespan, ensuring all instruments operate within the intended specifications and minimizing the risk of increased wear and tear. Furthermore, lab technicians can spot potential problems during the calibration process and address them before they significantly affect the equipment.

#2. Improving the Accuracy of Results

Although lab technicians account for a margin of error when conducting experiments or taking measurements, they can’t predict how an uncalibrated instrument will behave. Its readings may completely distort reality, affecting the interpretation of the results and their further application.

Even minor inaccuracies can have an enormous impact overall, especially in experiments where precision is paramount. Additionally, catching these mistakes is incredibly difficult, and once they are noticed, the only recourse is to recalibrate the equipment and repeat the entire procedure, which can be extremely time-consuming.

#3. Reducing the Risk of Hazards

Uncalibrated equipment can increase the risk of injury and work accidents, particularly when handling dangerous or toxic chemicals. Wrong readings from dispensing equipment could, for instance, cause a chemical spill or fire or otherwise endanger everyone working in the laboratory.

Though the possibility of an error can never be completely eliminated, lab safety is significantly improved when you properly maintain and calibrate lab equipment.

4 Types of Lab Equipment That Require Calibration

Types of lab equipment that require calibration include spectrophotometers, pipettes, balances and scales, pH meters, and all other instruments that provide measurements of various kinds.

In the following section, we will examine how to calibrate specific lab equipment and delve deeper into why such calibration is necessary.

#1. Spectrophotometers

Spectrophotometers are used to identify and quantify compounds in solutions by measuring their light absorption at different wavelengths. A typical spectrophotometer consists of a lamp, diffraction grating, a sample cuvette, a wavelength selector, and a photoelectric detector.

When a light beam from a lamp falls onto the grating, it is diffracted into its components and directed toward the sample solution in the cuvette. However, thanks to the wavelength selector, only the desired light component can reach the sample. Once it passes through, the solution absorbs some of it while the rest strikes the detector behind.

The readings on the detector provide enough information to calculate the solution’s light absorption, which can help identify the compound in the sample.

However, since spectrophotometers have many delicate, moving parts, yearly calibration is of the utmost importance. Lab technicians must check the light source’s intensity, the wavelengths’ accuracy, and the instrument’s ability to compensate for any stray light effects that may affect the results.

#2. Pipettes

Pipettes are lab tools used for transferring and dispensing small amounts of liquid at a high level of accuracy. In their most basic form, they have a simple dropper design, with a narrow glass tube that can be filled with liquid and a bulb-shaped top that creates a vacuum when squeezed. In their more advanced format, they precisely control how much liquid can be drawn into the pipette via a variable volume plunger system.

Despite their simplicity, some pipettes must be regularly calibrated; otherwise, their accuracy suffers, potentially leading to incorrect amounts of dispensed liquid during experiments. Calibrations should be performed every 3–6 months and every time the pipette is disassembled for deep cleaning.

#3. Balances and Scales

Lab balances and scales are crucial for measuring liquids and solids and ensuring that appropriate masses are used in chemical reactions. Since they must detect even the smallest variations in mass, these scales are highly sensitive and precise, requiring frequent maintenance and calibration.

Many modern scales come with a built-in calibration feature that can be triggered using a button or scheduled to activate automatically at regular periods. This type of calibration requires no human input, so it’s quite convenient, though not always entirely accurate.

As a result, modern scales should be occasionally calibrated in the old-fashioned way, using calibration weights. They can be repeatedly placed on the scales to check the device’s consistency or used in some of the other common calibration tests. The calibration of the instrument will be adjusted if not within tolerance.

#4. pH Meters

pH meters are used to measure a solution’s acidity or alkalinity, known as pH. This number ranges between 0 and 14, with 7 being neutral and pHs higher and lower than 7 representing basic or acidic solutions, respectively.

Essentially, pH meters measure the hydrogen-ion activity in a solution using two electrodes. Acids have more positively charged hydrogen ions and, thus, a greater potential to produce an electrical current, which electrodes use to determine the exact voltage of the solution. This is later converted into a more familiar pH number.

However, pH meters can deteriorate and become less reliable with frequent use, so it’s important to calibrate them regularly. For this, you should use pH7 and pH4 solutions and place the pH electrode in each for about a minute. The instrument should show the precise readings; if it doesn’t, adjust it until it does and repeat the process several times. If specifications cannot be met, the probe should be replaced.

How Often Should Lab Equipment Be Calibrated?

Lab equipment should be calibrated regularly, but the specifics depend on individual instruments and the instructions that come with them.

For instance, some tools, particularly those used frequently, require monthly calibration, while others need it quarterly or semiannually. The pieces you don’t use as often can even be calibrated on a yearly basis, though it’s not recommended to wait that long.

As a rule, labs should schedule comprehensive calibrations every 3–6 months while remembering to calibrate more frequently used instruments in between. However, if a laboratory is preparing for a major project or collaboration with another lab, the equipment should be calibrated beforehand to ensure that all measurements obtained are valid..

Another reason to calibrate equipment is after moving the equipment, even just across the room. Sensitive equipment can lose calibration from the slight forces of lifting, moving, and setting down the equipment.

How to Calibrate Lab Equipment

The specifics of how to calibrate lab equipment depend on the particular piece of equipment; some instruments have automatic calibration mechanisms, while others must go through a long calibration process. As a result, it’s difficult to outline the steps necessary for the calibration process that encompass all possibilities.

However, the overall process of organizing documentation and scheduling laboratory-wide calibration is always the same and should be conducted step by step.

Below, we will examine and explain each stage of calibrating lab equipment.

#1. Organize Instrument Details

Before you begin calibration, write down the details of each lab instrument you want to calibrate. Essentially, you should make equipment profiles containing information about the instrument type, serial number, manufacturer, calibration standards and history, and any additional notes.

Creating instrument profiles will assist you in tracking and managing the calibration process, as you’ll be able to consult the documentation if any questions arise. Furthermore, you’ll have easy access to each tool’s specific calibration requirements, maximizing efficiency and reducing the likelihood of making an error.

#2. Schedule Lab Calibration

You should calibrate different lab equipment at different time intervals—some on a monthly basis, while other pieces can go six months or more without any adjustments. The specifics depend on industry standards and the manufacturer’s recommendations, so it’s important to consult those before determining the calibration frequency for each instrument.

Once you do, write down the schedules in your instrument profiles for easy access and stick to them. Try to align calibration for several instruments at a time to improve efficiency and better organize your lab.

#3. Choose Calibration Standards

Your instruments should comply with national and global calibration standards set forth by the International Organization for Standardization (ISO) or similar regulatory bodies. These standards determine specific parameters and procedures required to calibrate each individual piece of lab equipment.

#4. Document Calibration Procedures

Lab instrument calibration procedures can be quite complex and include detailed instructions that are easy to misremember. Therefore, it’s essential to document these procedures for each instrument and include all details necessary for accurate calibration. That way, you minimize the risk of error and ensure the process is consistent and reliable.

#5. Conduct the Calibration

Once you’ve compiled the necessary documentation, chosen standards, and determined the frequency, you may begin calibrating laboratory equipment.

Follow the specific step-by-step procedures for each instrument until you complete the calibration process. Most importantly, keep a record of all measurements, adjustments, and deviations you’ve encountered. This information will help you track the instrument’s performance over time and assist in your subsequent calibrations.

#6. Validate Calibration Results

Finally, compare the measured values with the existing standards and tolerance limits to validate calibration results. After the calibration is completed, these values should match the standards; if they don’t, you’ll need to repeat the process or consider the possibility of a deeper issue.

The calibration process doesn’t end until every instrument has been adjusted to align with the set standards. Only then can you create or request a calibration certificate that guarantees your equipment’s accuracy and reliability.

International Calibration Standards for Laboratory Equipment

International calibration standards for laboratory equipment exist to ensure that lab instruments can consistently produce accurate and reliable results. The main globally accepted standard is ISO/IEC 17025, initially developed in 1999.

ISO/IEC 17025 outlines general requirements for testing and calibration laboratories, which include instructions on selecting, handling, calibrating, and maintaining equipment. In many countries, only labs with this accreditation type are considered valid and technically competent.

Labs that lack ISO/IEC 17025 accreditation can still be ISO compliant, but there’s no third-party confirmation of their validity and competence. In such cases, they can’t perform accredited equipment calibrations, so it’s often wiser to approach third-party calibration laboratories to complete the procedure instead.

When to Replace Lab Equipment Instead of Calibrating It

Calibrating lab equipment can ensure its proper functioning to a point, but it can’t repair instruments that are no longer usable. Thus, it’s important to recognize when laboratory tools can benefit from calibration and when it’s necessary to replace them.

Here are some reasons to consider replacing your lab equipment instead of calibrating it:

• Age. With time and repeated use, lab equipment deteriorates and becomes inefficient and difficult to maintain. As its repair and calibration needs increase, you’ll find that they outweigh its usability, which is a clear sign you should replace your instruments with newer ones.
• Repair costs. If your equipment is damaged, calibration may not be enough to restore its accuracy and ensure reliability. Instead, it might need to be repaired—a potentially expensive process, depending on the device and the scale of damage. If repairs cost more than purchasing a new instrument, it might be wiser to consider getting an upgrade.
• Modernization. Calibration can only ensure the instrument functions optimally within its capabilities, but it doesn’t improve its features beyond that. If you want more accurate, modern equipment, your only option is to replace it with newer models.

However, replacing lab equipment is a costly endeavor that smaller laboratories may be unable to afford. The solution may be buying pre-owned lab equipment, which tends to be sold at a fraction of the price.

If you opt for used lab equipment, Surplus Solutions offers all the essentials that have passed strict quality controls to ensure their safety, validity, and reliability.

Keep an eye out for new arrivals!

Key Takeaways

With our laboratory calibration guide, you’ll learn how to calibrate lab equipment and make the entire process of bringing it up to standards much simpler and more straightforward. The most important part is documenting all procedures; that way, you’ll have more specific guidelines for subsequent calibrations.

However, if calibration doesn’t improve your equipment’s performance, Surplus Solutions offers high-quality replacements for all essentials at an affordable price. So, consider carefully whether to calibrate lab equipment or overhaul it entirely.

How to Calibrate Lab Equipment FAQ