How to Measure EMF
How to Measure EMF: The Art of Knowing What You Are Studying
There are a lot of people concerned about electromagnetic fields (EMF) and electromagnetic radiation (EMR or also known as radio frequency (RF)). People want to know how to measure EMF. So much so, that they purchase detectors and meters for themselves and attempt to study their own property and homes. It is great to take responsibility for your own concerns! However, there are likely many things that could be confusing your personal emf testing and rf testing assessments.
The electromagnetic spectrum is organized by frequency. Generally, lower frequency radiation is on the left, and higher frequency radiation is on the right. See the above graphic.
The properties of electromagnetism change at different frequencies and electric and magnetic fields behave differently along the spectrum. A material that is transparent to visible light can be opaque to infrared light, but then again transparent to radio frequency radiation (e.g., glass). Chrome is highly reflective to all of these frequencies, but nearly invisible to IR cameras because it reflects much more heat energy than it emits. So how do you measure the temperature of a chromed device if you cannot attach temperature sensors (thermocouples) to it?
Measuring Magnetic Fields
Meters measuring magnetic fields strength analyze the flux (changing field properties) of the magnetic field. A meter in motion will not measure this accurately, because measurements will be artificially elevated as you move through a magnetic field. While an accurate quantitative measurement cannot be made while moving, a qualitative measurement can be made to show places where more investigation is recommended. Walking through a building with a magnetic field meter taking real-time measurements is still an effective strategy of finding “hot spots.”
Measuring Radio Frequency (RF) Radiation
Higher than expected radio frequency (RF) power density can be just as confusing. RF can act sort of like X-rays, penetrating through many materials, reflecting off others. This can produce apparently high power densities in certain areas and make finding the source of those RF radiations more difficult. Using separate RF meters or antennas with the capability of omnidirectional AND more focused targeting can be useful in RF testing.
If you find areas that raise your concerns it is best to refer to an expert in the field – much like a medical generalist refers to a specialist. A qualified EMF specialist is trained specifically in the use of high-quality equipment, has area-specific knowledge, and has experience with many different buildings and situations.
EMF Testing Services
If you bring your EMF concerns to Healthy Building Science, it usually makes our jobs easier by giving us a heads-up as to where to start our investigation and EMF testing. Don’t be surprised if our investigation brings unforeseen conclusions! Often we deliver better than expected news and peace of mind, and no additional measures are recommended or the fix is more simple than you think.
Healthy Building Science is an environmental consulting firm which provides EMF testing, emf surveys, emf consultations and RF testing for the greater San Francisco Bay Area and all of Northern California.