Disclaimer: This article describes unique situations where it might be beneficial for an organization to develop its own in-house EMC test capability and purchase an EMC chamber. It is in no way meant to disparage the many excellent third-party test facilities that exist throughout the world today.

Are you considering the purchase of an EMC chamber for in-house testing? If so, what factors should you consider for determining if the investment is a wise choice or if the continued utilization of a third-party test facility is the better option? For some, the decision is easy. The volume of products they intend to develop that require EMC testing is so low that the cost to bring EMC testing in-house is clearly not justified. For others, they may have a lot of new products in development (or plan to), and taking them to an outside EMC testing facility on a regular basis is not only costly, but it is also inconvenient and time-consuming. For those in this latter group, trying to decide if they should bring EMC testing in-house is not always a straightforward decision.

To ease some of the thought process that is involved in making this decision, this brief article can be consulted as it highlights important things to consider when determining the return on investment (ROI) for an in-house EMC chamber.

Return on Investment Calculation

Management will likely require some form of ROI calculation before they will release corporate funds to purchase such an expensive item. The calculation is basic and can be found on the internet however, your firm may already have its own unique form and calculation that must be completed and reviewed by an accountant (or other business professional) prior to requesting management approval to purchase an EMC chamber. What are some of the things that should go into your unique and customized ROI calculation?

Here are some of the basic items to consider for inclusion in the ROI calculation:

  1. Number of expected test events over the next x number of years (x might be three, four, or five, for example).
  2. Cost of item 1 above if conducted out-of-house at a third-party test facility (include travel cost and time, lodging, meals, flights, in addition to test fees for each expected test event).
  3. Cost of the EMC chamber and all associated equipment (antennas, turntable, amplifiers, spectrum analyzers, cables, filters, line impedance stabilization networks, etc.).
  4. Cost to install the chamber.
  5. Cost of calibration and chamber verification tests over the next x numbers of years.
  6. Cost of in-house labor and staff to run and maintain the EMC chamber and all associated equipment over the next x number of years.
  7. Cost for electricity to run and light the chamber over the next x number of years.
  8. Cost to train in-house staff to run the chamber.
  9. Cost for accreditation of the tests to be performed in the chamber and laboratory management.
  10. Depreciation of the chamber over x number of years.
  11. Cost of any other item you can think of.

Ambiguous Items to Include in the ROI Calculation

After you put all of the above basic items into your ROI calculation you may still end up, on paper, with a number that does not fully justify the procurement of an EMC chamber. That does not necessarily mean that it is a bad decision. You may need to include some of the more ambiguous items in your ROI calculation before you can justify the purchase. For these ambiguous items it’s often tougher to put a hard dollar amount to them, but they can and should also be used to make the decisions to purchase an in-house EMC chamber.

Below are some of the more ambiguous items to consider when developing the ROI calculation for an in-house EMC chamber.

  1. With an in-house chamber, you can customize the configuration of filtering, power, turn-table size, size of the chamber, cooling, heating, size of the doorway, lighting, EUT monitoring, size of antennas, etc. to accommodate the unique requirements that only your EUT has. When using a third-party facility, you must utilize whatever configuration they have available, which may or may not require extra effort on your part to “make it work” for your unique EUT setup.
  2. Your in-house chamber is available for testing any time you need it (24/7).
  3. If your EUT fails testing, and you need to go into troubleshooting mode, you don’t have to worry too much about the clock ticking and over-time, getting removed from the chamber, and wasting expensive third-party lab test fees.
  4. You will never again go back to your organization with a non-compliant product, after having spent a lot of time and money testing it at a third-party test facility trying to obtain passing results.
  5. Engineering expertise (those who know the product and the design), are on-site, nearby, and available to help troubleshoot the EUT as required.
  6. Your facility has more options for fixes (capacitors, ferrites, resistors, etc.) should they be required.
  7. There are technicians on staff who are well-trained in making modifications on the fly should modifications to pass be required.
  8. Determining if a minor modification to the product or if a part replacement for an end-of-life component causes a non-compliance is much quicker and easier.
  9. The time required to get the product to market is much quicker.
  10. Maintaining continued compliance is easier. You can re-test your device anytime you suspect a change might have been implemented that may affect compliance.
  11. Customer-witnessed tests can be scheduled anytime it is convenient for you and your customer.

Conclusion

These and other luxuries often do not exist when you take your product to a third-party test facility. What value proposition do they provide and how do you incorporate them into an ROI calculation? That is a question that only you and your firm can decide.

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