*EFFECTIVE January 1st, 2019 ScanTech will no longer perform residential testing OR consulting for homeowners and tenants – all services are COMMERCIAL ONLY. Instead I will redirect you to a page for resources to other companies and common questions – CLICK HERE.
WHAT IS AN EMF SURVEY / OR ELECTROMAGNETIC FIELD TESTING?
It is a detailed survey of the electromagnetic sources and EMF fields of potential influence in a given room, building or other area of interest. Depending on the needs of the client, the following fields are measured:
AC 60 Hz Magnetic Fields: Magnetic fields generated by CURRENT running through the main electrical wiring in the building
AC 60 Hz Electric Fields: Electric fields generated by VOLTAGE running through the main electrical wiring in the building
DC Magnetic Fields: There is always a DC magnetic field from the Earth that is typically 550 milliGauss (mG) but other equipment and the shaping of the geomagnetic field can alter the field density; even lower it in some cases.
RF / Microwave Radiation Fields: Radio frequency fields from wireless equipment and in some cases generated by arcing, welding activities, etc.
Anomalous readings and EMF field intensity levels of concern are noted, documented and investigated. Consultation on what can be done is provided onsite and a written report given.
Procedure for an EMF SURVEY / Electromagnetic Field Service
1) You make an appointment with us by calling or emailing through the Service Request Form just above – we can often do evenings and weekends on relatively short notice though RUSH FEES may apply.
2) We can email a copy of our EMF Survey agreement so that you know what to expect as far as guarantees. Upon request, this can also include a sanitized sample report with explanations of range such as shown below.
3) After meeting with you or your representative on site, then if everything is amenable, you sign the EMF survey agreement which gives us permission to begin. If you or another individual who is authorized to sign contracts on your behalf are unable to meet onsite, then the agreement must be signed before onsite testing begins.
4) We deploy the EMF scanning equipment and begin recording readings in each living area of the residence or structure. This typically takes 1-2 hours (or more depending on the scope of work) and you are welcome to follow us and take notes or ask questions.
5) After finishing, IF you have opted for the WRITTEN and / or graphical reporting option we give you a rough carbon copy of the EMF field report along with a verbal consultation regarding our prognosis and recommendations. (provided you are paying for a Written or Graphical Analysis type survey.
Payment is typically due at that time – otherwise an administrative billing fee may apply.
6) We will send a finished formal report by email within 3-5 business days. Guide to interpreting results below.
Guide to Interpreting your EMF Inspection Reports (Home & Commercial)
STANDARD UNITS FOR MAGNETIC ELECTRIC & RF FIELDS
60 Hz AC and other ELF Extremely Low Frequency MAGNETIC FIELDS – units in milliGauss (mG)
60 Hz AC and ELF ELECTRIC FIELDS – units in V/m or Volts per meter
RF (RADIO FRQUENCY) fields – units usually in uW/cm^2 which is shorthand for microWatts per centimeter squared
For a list of unit conversion tables
ROOM EMF MEASUREMENT EXPLANATION
Each room has a low and high range.
Living Room 0.35 – 1.17
This translates to a low of 0.35 mG to a high of 1.17 mG. It is much easier to give a range rather than a true arithmetic mean as that would require sampling a large number of data points in every point in the room which is neither cost effective or necessary. All readings are taken at 1 meter above the ground which is the recommended IEEE height to record readings during an EMF survey. This height was chosen to represent an average center of body mass for both adults and children.
In some cases, such as in sleeping areas, measurements are taken from about where a body would lie on the mattress from head to foot to get a better idea of the EMF exposure during sleep.
Hot Spot – a high spot is an area that exhibits a higher than the normal or ambient field found in a particular room during an EMF home inspection.
EXAMPLE: Garage 0.18 – 0.6 mG Hot Spot 15.8 mG + near breaker box.
This translates to the observation that the typical low for the garage is around 0.18 and a typical high is 0.6, but in the vicinity of the breaker box (typically within a few feet or less) the fields are elevated due to all of the convergent circuit branches that meet at that one point. There is generally a comment such as “Normal” which means this is a customary and ordinary field measurement for this type of feature. It would only be a concern if the field is high enough and pervades into other living spaces where the occupants spend a substantial amount of time. Transient passage or time spent such as in house areas such as utility rooms, garages, closets, hallways, etc. are generally not an issue.
Note: Aerial survey style reports of the exterior normally accrue additional charges.
ACTUAL CASES FROM EMF INSPECTIONS
A North Dallas suburban home had elevated EMF (25 mG +) throughout several areas of the home and in the front yard? CAUSE: An improperly wired branch circuit that had been grounded to the sprinkler system.
In Coppell, an expensive two story was built within 30 yards of some 500 kV lines. The resulting field throughout the home was 35 – 50 mG. Mitigation considered impractical.
Fort Worth, TX. – An improperly wired 3-way switch caused elevated EMF on a wall in a children’s playroom. Recommendation was to repair the wiring utilizing a knowledgeable electrician.
Allen, TX. – A biologist was concerned about cell towers in a neighborhood that her family was considering moving into. Findings: Tower was too remote to have any measurable effect on RF / microwave levels over background.
Carrollton, TX – A series of homes constructed by a conscientious builder were next to a 230 kV line. Amazingly, the EMF at the property lines generally did not exceed 2.0 mG.
Roanoke, TX – ScanTech was contacted by a Fortune 500 company to evaluate the safety and equipment interference levels of a switch room. While EMF was generally within all but the strictest suggested standards, it was found that RF levels would spike beyond OSHA recommended guidelines. Redesign and re-deployment of the network infrastructure is going forward.
Q. How much is a milliGauss (mG) ?
A. It is 1/1000 of a gauss and is also equal to 100 nanoTesla. An average home with good wiring practice that is a sufficient distance (see main FAQ to the right) from power line influence will typically read 1 mG or less.
Q. What is the difference in Specific Absorption Rate SAR (watts per kg) and normal RF measurements such as watts per cm squared?
A. There is often a lot of confusion about this. SAR is a measurement that generally applies to the NEAR FIELD (within one wavelength) of an RF emitting device such as a cell phone and relates to the amount of energy a human body absorbs from that device. This requires a laboratory type setup with very expensive equipment and 3-D modeling software.
Most standard RF measurements deal in FAR FIELD (beyond one wavelength) energy modeling, which is a very different type of exposure. The two readings cannot really be converted back and forth.
Q. What EMF level limits / specifications are pacemakers, ICDs, cardiac devices and biomedical implants designed to work in safely?
A. It differs enough that it is recommended that you either contact the doctor / surgeon / medical center involved and / or the manufacturer of the unit in question for the safest answer. You need the make and model number, but ScanTech can act as a technical liaison and interpret the numbers for a proper workplace / industrial survey.
Here are some example specs that have been seen:
DC Gauss Field: 1 Gauss
AC Gauss Field: 1 Gauss
50/60 Hz Electric Field: 6 kV per meter
High Frequency Field: 150 volts per meter
RF Energy: 2.6 mW per cm squared
ScanTech has performed a number of biomedical implant surveys and has both the equipment (several meters are required) and the education / experience to perform this professionally.
Q. What recommendations do you have for Low EMF construction?
A. There are several things that can be looked at from the outset of construction or as a part or retrofitting an existing home.
Low EMF lighting such as LED lighting is an excellent choice plus it saves money through increased energy efficiency and reliability. Fluorescent lamps should generally be avoided as they can have higher EMF & RF signatures and induce electronic noise (also known as “dirty electricity”) into the 120 VAC mains power.
Metal or shielded metal conduit for electrical wiring. (proper grounding shields electrical fields)
Use of flat screen monitors vs. CRT monitors with a significant magnetic field.
Correct wiring practice for multi-locational lighting (lights with two or more switches controlling) by using 3 wire runner.
Avoiding ground loops through improper wiring and malfunctioning equipment.
Do not connect neutrals from separate branch circuits.
Shielding heavier point source fields such as those found near breaker boxes with mu metal or hydrogen annealed plate.
Q. Are there low EMF appliances that you can recommend?
So far, applicable electronic and electric devices which are marketed as low EMF are limited to phones, hair dryers and computer monitors.
For phones, you can look up the SAR or use some kind of low EMF headphones to keep the radiation away from your head.
Low EMF hair dryers use an elongated tube to route hot air to your hair without placing the motor/heater assembly close to your head.
Flat screen monitors are usually superior to CRT monitors in many ways including lowered eyestrain and EMF fields. Special transparent shields are available for those who need to use an older CRT.
For major home appliances, the main source of concern would be the refrigerator because it is always on as compared to ovens, dishwashers and washing machine/dryers. It is difficult to recommend specific makes and models because the specs are not usually published and the manufacturer periodically designs and markets new appliances constantly.
Prudent avoidance is one of the best solutions – once the appliance is on, move away from the area until it is done. Otherwise, flexible shielding may be an option.
Q. My family is thinking of purchasing an electric / hybrid vehicle such as a Toyota Prius, but I have heard or am concerned that the EMF fields are unsafe. What do you recommend?
A. That ScanTech meet you at the dealership for a survey to measure the fields at different points in the vehicle and to address your concerns. The fields in an electric vehicle can be high, but vary from one individual vehicle to another and shielding of the passenger compartment could mitigate any concerns.