Calibration Intervals – What You Need to Know About Them

Calibration intervals are a defined period of time between calibrations for measuring equipment. They are established to make sure that the measuring equipment operates within the interval time frame.

A well-defined calibration interval balances the cost of calibration, the inconvenience of the process and the need to keep the test instruments performing within their specification. It also minimizes the risks that come with inaccurate measurements.

Initial Calibration Intervals

The first step is to set an initial calibration interval for the measuring equipment based on the manufacturer’s recommendations. This is especially important if you have no prior experience with the equipment.

If you are using similar equipment, use your experience to set the calibration interval for the new equipment.

Important Questions to Ask

  1. Some questions that you must ask when you set the initial calibration include:
  2. How stable is the equipment?
  3. Will the equipment be used frequently or rarely?
  4. How critical are the measurements that the equipment will make?
  5. What is the risk of damage?
  6. What are the environmental conditions in which the equipment will be used?
  7. What are the risks associated with using a piece of equipment that is not calibrated?
  8. Are there any regulatory obligations pertaining to calibration intervals?

After setting the initial calibration intervals, make sure you keep good calibration records. The records should include:

  1. Equipment’s manufacturer
  2. Model number
  3. Location where the equipment is used
  4. Identification numbers associated with the equipment
  5. Procedure number for the calibration procedure used
  6. Frequency of calibration that has to be performed

The records should also have data on the calibrations and measurements performed, such as:

  1. Date of the calibration
  2. Details of the technician who performed it
  3. The equipment characteristic that was calibrated,
  4. Measurements of that characteristic before and after the calibration

What is Optimal Calibration Interval?

An optimal calibration interval is one that balances the following things:

  1. Cost of instrument calibrations
  2. Downtime associated with the calibration process
  3. Ability to meet the stated specifications
  4. Risks that you face with out-of-calibration equipment’s performance

Too short an interval can result in higher calibration costs and increased downtime; too long an interval could lead to a risk of recall, out of tolerance measurements, unscheduled maintenance and inaccurate measurements.

Calibration Interval Adjustment Methods

  1. Simple Adjustment Method

In this method, the interval is adjusted after every calibration or series of calibration set between the minimum and maximum values.

You can modify this method by minimizing the sequence of fluctuating adjustments. Or you can make adjustments only after the equipment has been in-tolerance or out-of-tolerance during a specific number of calibrations.

  1. Reliability/Performance-Based Methods

These include taking successive calibration results and calculating a reliability number based on the percentage of times the item meets or fails to meet its specification.

You can use a simple table to determine the interval based on the reliability number. These methods establish more frequent calibration for equipment with uncertain reliability to make sure that they meet the required specifications.

  1. Statistical Analysis Methods

Statistical Analysis methods make adjustments by performing a technical analysis of critical measurement data results instead of using calibration pass/fail criteria. You can obtain the measurement data through calibrations, intermediate checks, interlaboratory comparisons or proficiency tests.

Setting the right calibration interval will ensure two important things. First, it gives you more confidence in the results that the equipment produces and second, it enables you to make better decisions based on those results. If you need any help with the calibration of equipment and setting the calibration interval, please get in touch with RS Calibrations. Our team will assist you in achieving the same.

No Comments

    Leave A Comment

    1047 Serpentine Lane, Suite 500, Pleasanton, CA 94566
    Call us today 1-877-799-0922
    Malcare WordPress Security