Cellphone EMF-Blocking Products Put In A Real World Test

SAN FRANCISCO (KPIX 5) -- Whether or not you're concerned about the "potential" health effects of the radio frequencies emitted by your mobile devices, the sale of RF-blocking products is quickly becoming a lucrative industry.

While some argue that the product claims are too good to be true, testing commissioned by KPIX 5 found that some of these products really do live up to their claims.

But a warning – we also discovered that when not used properly, some RF-reducing products may actually increase exposure to electromagnetic frequencies.

The Truth About "FCC Certified" Lab Tests

For years, the Federal Trade Commission has issued warnings about "Cell Phone Radiation Scams", citing products that claim to "significantly reduce exposure from these electromagnetic emissions." Still, a growing number of products make claims that imply they block up to 100% of the "potentially harmful" radiation emitted from our mobile devices.

Take a closer look at the product claims. Many refer to their "shielding technology" and not the product itself. In many cases, the "FCC Certified" labs they cite are actually testing how much RF the raw shielding material can block. They're testing the materials used in the products. They're not testing how much RF the actual products block while on a real-world phone.

Even the labs that do use a cellphone don't generally test the products while on a real-world call. Instead they use a controlled signal generator that emits a constant signal. In the real world, RF fluctuates along with the cellphone signal and power.

Experts warn that these products can perform differently in different real-world environments. Depending on the position of each phone's antenna, its relation to the nearest cell tower, and how the product impacts the phone's signal, they say RF shielding products may even increase RF emissions and exposure.

Our Real-World Tests

We wanted to find out just how much RF some of the most popular products might actually block outside of a lab – in the real world. So KPIX 5 enlisted the help of Electrical Engineer and EMF Specialist Michael Neuert of the EMF Center.

We tested a variety of cellphone cases and garment shielding products including the Safe Sleeve, Defender Shield, RF Safe  cellphone "flip" cases, and the Pong cellphone case which does not have a cover over of the face of the phone. We also tested the Belly Armor blanket, nursing cover and boxers as well as an anti-radiation tank top sold by OurSure on Amazon.

Since people generally don't use these products in lab-like environments with 0 ambient RF frequencies, we performed the testing in real-world San Francisco apartment.

The Meters

Our tests wre conducted with three RF meters, set at fixed position next to the iPhone. Our primary meter was the Gigahertz Solutions HFE 59B, a professional RF instrument. We also used a TES 593 (Mid-Range Consumer Grade Instrument) and the Acousticom 2 (Low-Range Consumer Grade Instrument) to compare/confirm the increases and decreases in RF and for visual reference.

The Readings

We began by getting a baseline of ambient RF in the room at the location of our testing. We then recorded a baseline of the cellphone RF while on an active call with no case. And finally, we measured the reduction in that baseline (still on the active call) using a variety of different cases and RF reducing products – all at the same set distance from the phone.

To account for fluctuations in the real-world cellphone signal, we recorded peak readings over a short period of time and then averaged a series of those readings over a longer period.  We repeated our testing for each product later in the day to confirm repeatable results.

The Positions

We tested each phone case in 4 different positions:

Forward Facing CLOSED with the front cover/flap properly closed over the face of the phone and forward facing toward the meters. This measured the RF that would be theoretically directed at your head if you used the phone properly with the case closed – listening to the call through the ear hole in the front cover.

Rear Facing CLOSED with front cover/flap closed, but with the phone turned around so the back of the phone was facing the meters. This was intended to measure the RF that would be directed out of the back of the phone.

Bottom facing CLOSED with front cover/flap closed, but with the phone placed flat on its back with the bottom of the phone/speaker facing the meters. This was intended to measure the RF out of the bottom of the phone case.

Front facing OPEN with the front cover/flap flipped around behind the phone so the screen is exposed and facing the meters. This was intended to measure the RF that would be directed at your head if you used the phone with the case open and the screen pressed against your ear.

Note: The cellphone case manufacturers tell us they generally only test the phone in the first, standard,  position. 

We tested the garments in a similar setup with the fabric between the phone and the meters. We also tested the garments while sitting on a couch, holding the Gigahertz Solutions monitor against my pregnant belly under the product (blanket/nursing cover) and measuring the reduction of the RF from my cellphone in my hand at normal texting/web-surfing distance.

The Phones

We tested the products using both AT&T and Verizon iPhones.

The Results

Each of the cellphone cases did substantially reduce the amount of RF coming out of the face of the phone, when the cases were used properly.

Three of the four cases, Safe Sleeve, Defender Shield, and RF Safe, are intended to be used with the shielded front cover of the flip case closed over the face of the phone - even while on a call.

Neuert points out that may not be intuitive for the average cellphone user. "I would know that because I know how these work but I think other people might miss that point, he said.

The RF Safe case was the only case to explicitly say on the product packaging itself that the case should only be used with the front flap closed while on a call.

Our tests found the flip cases reduced RF by an average of 85%-90% out of the face of the phone, when used properly, with the front cover closed.

However,  depending on the cellphone network and position of the case, we also found some cases actually amplified – or increased - the amount of RF coming from the phone.

In one case, with the front of the flip case open and folded behind the phone – as most people use flip cases in the real world - the RF blocking cellphone case actually double the amount of RF coming from the face of the phone.

Neuert explains, "These frequencies usually get reflected like a mirror so you're seeing what used to go out back of it getting reflected to you."

We also tested the Pong cellphone case which was the only RF-Reducing cellphone case that does not utilize a shielded front cover. In a statement Pong stated that handheld RF meters like the ones we used were not "suitable for quantifying the effect of (its) case."

Neither RF Safe nor Defender Shied responded to our repeated requests for comment. Safe Sleeve, however, was very responsive and noted that testing outside of a lab "with ambient and uncontrolled RF may result in unreliable readings."

The Real World Concerns

Experts agree that these products do preform differently outside of a lab. That is the concern.

For instance, our tests found that same case in the same location blocked more RF on a Verizon iPhone than it did on an AT&T iPhone. Neuert and other independent EMF experts tell us that was likely due to our proximity to the nearest respective cellphone towers. In a different location, or even facing a different direction, we may have seen different results.

Those findings were the primary reason we decided not to publish our exact readings and compare the products directly to each other. The one thing our tests did confirm is that the RF-blocking capability of any product can vary greatly depending on a number of factors, including location, cellphone network and how you are using the case.

The cellphone case manufactures confirm they generally don't test their products on an actual phone in different real world positions.

The Garment Tests

We also tested a series of RF blocking products that are intended to be worn on your body.

Though Neuert says there is an obvious downside to the garment products. "The problem with garments is that you're not covering your whole body."

However, all of the garment shielding products we tested blocked 90-99% of the cellphone RF, when covering the phone itself, and 80-95% when used as directed - covering your body, your baby or in this case, the test meter.

Reducing RF

Bottom line, Neuert says shielding is tricky. "In most cases, the shields, when used in the correct way, will reduce your exposure significantly. But under the right circumstances, they can actually make things worse."

With or without products, Neuert says, the best way to reduce exposure is to increase your distance and decrease your length of use. Or better yet, keep your phone in airplane mode as often as you can.

Neuert also recommends using speakerphone over wired headsets. Experts say the wires can still conduct some EMF. However, they recommend wired headsets instead of Bluetooth.