Safe Operating Distance 
X RF instruments used in accordance with manufacturer s instructions will not cause significant expo¬ 
sure to ionizing radiation. But the instrument s shutter should never be pointed at anyone, even if the 
shutter is closed. Also, the operator s hand should not be placed on the end plate during a measurement. 
The safe operating distance between an XRF instrument and an individual depends on the radiation 
source type, radiation intensity, quantity of radioactive material, and the density of the materials being 
surveyed. As the radiation source quantity and intensity increases, the required safe distance also increas¬ 
es. Placing dense materials, such as a wall, between the user and others and a source of radiation, further 
help to ensure that the possible exposure to radiation is minimal. 
According to NRC rules, a radiation dose to an individual in any unrestricted area must not exceed 2 
millirems per hour. One of the most intense sources currently used in XRF instruments is a 40-millicurie 
1() , Cd (Cd-109) radiation source. Other radiation sources in current use for XRF testing of lead-based 
paint generally produce lower levels of radiation. Generally, an XRF operator following manufacturer s 
instructions would be exposed to radiation well below the regulatory level. Typically, XRF instruments 
with lower gamma radiation intensities can use a shorter safe distance, provided that the potential expo¬ 
sure to an individual will not exceed the regulatory limit. 
No one should be near the other side of a wall, floor, ceiling or other surface being tested. The operator 
should verify this prior to initiating XRF testing activities and check on it during testing. 
Finally, the effectiveness of the instrument s radiation shielding should be assessed every 6 months using 
a leak test. The XRF manufacturer or owner s manual can be consulted to obtain vendors of leak test kits. 
If these safety practices are observed, the risk of excessive exposure to ionizing radiation is extremely low 
and will not endanger any inspectors or occupants present in the dwelling. 
Each quarter, Syracuse receives sample kits with four concentration levels for each of three 
matrices: paint chips, soil, and dust wipes. The city analyzes these samples and sends the results 
back to ELPAT for evaluation. Performance ratings are based on accumulated results over four 
rounds. The acceptable range is based on consensus values from all laboratories. A laboratory s 
performance for each matrix is rated as proficient if either of the following criteria are met: in 
the last two rounds, all samples are analyzed and the results are 100 percent acceptable; or, 
three-fourths or more of the accumulated results over four rounds are acceptable. Syracuse has 
consistently been rated as proficient using XRF. 
For more information on the ELPAT Program, visit <www.aiha.org/LaboratoryServices/html/ 
elpatl.htm> or contact the Laboratory Accreditation Department at AIHA, (703) 849-8888. 
6.4- Health and Safety When Using XRF 
Guarding Against Radiation Hazards 
Portable XRF instruments used for lead analyses contain radioactive isotopes that emit X-rays 
and gamma radiation. Proper training and handling of these instruments is needed to protect 
the instrument operator and any other persons in the immediate vicinity during XRF use. The 
XRF instrument should be in the operator s possession at all times. The operator should never 
defeat or override any safety mechanisms of XRF equipment. The City of Syracuse has 
dosimetry badges that are worn by each of the XRF operators whenever the instrument is in 
Analyzing Lead Dust Samples Using XRF Technqlpgy 
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