Frequently Asked Questions: Spiking

What is Spiking?

Spiking is an important part of any QA/QC plan, and is intended to ensure the accuracy of one's radon measurements when using passive detectors (such as Electret Ion Chambers). When you send in your detectors for spiking, we will expose them inside our radon chamber (which has a known radon concentration known as the "target value"), and then mail them back to you. It is your job to analyze the detectors, which will determine your accuracy (and bias) when compared to the known target value of Rad Elec's radon chamber.

Rad Elec's Spiking Service helps the user to detect potential inaccuracies with the passive detectors themselves, as well as to test the accuracy of users to analyze their own equipment and detectors correctly.

Do I need to perform Spiking measurements?

Both AARST-NRPP and the NRSB require that listed companies and individuals perform spiking measurements through an accredited radon chamber at a rate of 3 per 100 measurements, with a minimum of 3 per year and a maximum of 6 per month. However, even if nost listed, all organizations and individuals using passive detectors should send their detectors in for spiking to ensure the accuracy of their measurements.

How often do I have to send in my E-PERMs® for Spiking?

The U.S. Environmental Protection Agency recommends that all organizations using passive devices expose, record and interpret the results of three spikes per 100 measurements (as averaged over the anticipated number of measurements during a several month period), with a minimum of three per year and a maximum (although more may be conducted) of six per month.

What is the procedure for Rad Elec's Spiking Service?

  1. Print out the Spiking Service Form (located here) or create a new spiking record from within the Radon Report Manager software.
  2. Thoroughly clean both the electrets and chambers with nitrogen.
  3. Read and record the initial voltages of the electrets (making sure each electret has over 300 volts), and load the electrets into their chambers. Make sure that the chambers are tighly closed.
  4. Fill out the Spiking Service Form with your company's information, addition to columns 1, 2, and 3 of the table. Make a copy of this form for your records, and then send the form (along with your E-PERMs®) to Rad Elec.
  5. Rad Elec will expose your E-PERMs® in our radon chamber. We normally perform spiking on Mondays and Wednesdays, and each exposure lasts for approximately 48 hours.
  6. Once we remove your detectors from the chamber they will be sent back to you, along with the Spiking Service Form. Rad Elec will fill out the deployment times on the Spiking Form, in addition to the background gamma levels and the target radon concentration.
  7. After you receive your detectors, read the electrets' final voltages and calculate the radon concentration using the information provided on the Spiking Service Form. Compare this with the target radon concentration written on the form.
  8. If using the Radon Report Manager software, please watch our comprehensive tutorial in order to better understand this process.

Is Rad Elec's radon chamber accredited?

Yes! Rad Elec's radon chamber is NRSB-accredited as a tertiary radon chamber. Its accreditation identifier is #TRC6002.

What are the "Do's and Do Nots" for Spiking?

  • DO load the electrets into their respective chambers. This is what makes an E-PERM® / Electret Ion Chamber.
  • DO print out the Spiking Service Form, either from our website (located here) or from within the Radon Report Manager software.
  • DO keep extra copies of your spiking forms and spiking reports. This is your responsibility, and helps safeguard your data.
  • DO NOT perform spiking at the same time your voltage reader is being calibrated. If the reader has to be adjusted during calibration, it could possibly bias your results. It is recommended that you have your reader calibrated prior to performing the spiking (if it is due for calibration).

Where can I find the Spiking Service Form?

You can find the Spiking Service Form right here.

How much does the Spiking Service cost?

The Spiking Service costs $20 per E-PERM® to be exposed in our radon chamber.

What happens if one of my E-PERMs® falls outside of the ±25% control limit?

In the rare event that your results differ by more than 25% from Rad Elec's target value (the known radon concentration inside our radon chamber), then you should investigate the causes. It is not mandatory that you repeat the Spiking Test, since you are only required to perform Spiking measurements and investigate your results; in other words, there is no "passing" or "failing" a spiking test.

However, Rad Elec strongly encourages you to find out why this discrepancy exists -- typically, this may be caused due to the electret being accidentally touched during the initial or final voltage readings, or due to the presence of particulate and fibers on the electret surface. Sometimes this can be due to a filter inside one of your ionization chambers becoming loose. Always clean each chamber and electret prior to taking your initial readings, and you should find your results to be very close to our target.

To encourage our customers to discover the causes behind these discrepancies, Rad Elec offers free repeat spiking tests for detectors that exceed the ±25% control limit (apart from the shipping costs), if requested within 30 days of the initial test. Please remember to write "REPEAT" at the top of your Spiking Service Form, so that we can remember not to charge you for this repeat test.