Assessing electric field strength inside a anatomical hand model caused by a magnetic deactivator device for Electronic Article Surveillance System labels

Abstract

Assessing electric field strength inside a anatomical hand model caused by a magnetic deactivator device for Electronic Article Surveillance System labels Schneeweiss P, Hirtl R, Schmid G. Assessing non-sinusoidal in situ electric field strength inside a detailed anatomical hand model caused by a magnetic deactivator device for EAS labels. J Radiol Prot. 2023 Feb 6. doi: 10.1088/1361-6498/acb955. Abstract To evaluate the localized magnetic field (MF) exposure of the cashier's hand due to a particular de- magnetization device (deactivator) for single-use labels of an acousto-magnetic (AM) electronic article surveillance (EAS) system, comprehensive measurements of MF near the surface of the deactivator and numerical computations of the induced electric field strength Eiwere performed in high-resolution anatomical hand models of different postures and positions with respect to the deactivator. The measurement results for magnetic induction B were assessed with respect to the action levels (AL) for limb exposure, and the computational results for Eiwere evaluated with respect to the exposure limit values (ELV) for health effects according to EU directive 2013/35/EU. For the ELV-based assessment, the maximum of the 2 x 2 x 2 mm3averaged Ei (maxEi,avg) and the respective 99.9th, 99.5th, and 99.0th percentiles were used. As the MF impulse emitted by the deactivator for de-magnetization of the AM-EAS labels was highly non-sinusoidal, measurement results were assessed based on the weighted peak method in time domain (WPM-TD). A newly developed scaling technique was proposed to apply the WPM-TD also for the assessment of the (non-sinusoidal) Eiregarding the ELV. It was used to calculate the resulting WPM-TD based exposure index (EI) from frequency domain computations. The assessment regarding the AL for limbs yielded peak values of magnetic induction of up to 97 mT (measured with a 3 cm2MF probe on top of the deactivator surface) corresponding to an EI of 443 %. However, this was considered an overestimation of the actual exposure in terms of Eias the AL were defined conservatively by intention. A WPM-TD based assessment of Eifinally led to worst case EI up to 135 %, 93 %, 78 %, and 72 % when using the maxEi,avg, 99.9th, 99.5th, and 99.0thpercentiles, respectively. pubmed.ncbi.nlm.nih.gov ... it can be hypothesized that the ICNIRP 2010 reference levels may not be conservative in the sense that even when meeting the reference levels, compliance with the basic restrictions is not guaranteed, although an additional reduction factor of 3 was introduced when deriving the reference levels from the basic restrictions, with the intention to account for numerical uncertainties. In particular, this has significant implications for workplace safety, as according to the definition in 2013/35/EU, a workplace can be assumed compliant if the AL are met without any further investigation with respect to the ELV. All in all, the investigated device must be considered at least borderline to non-compliance and precautionary measures are recommended, e.g., ensuring a distance of 50 mm to the deactivator surface to ensure compliance. All in all, the investigated device must be considered at least borderline to non-compliance and precautionary measures are recommended, e.g., ensuring a distance of 50 mm to the deactivator surface to ensure compliance.

AI evidence extraction

Main findings

Measurements near the deactivator surface found peak magnetic induction up to 97 mT (3 cm^2 probe on top of the surface), corresponding to an AL-based exposure index of 443%, which the authors describe as a conservative overestimation for induced electric field assessment. A WPM-TD-based assessment of induced electric field reported worst-case exposure indices up to 135% (using max Ei,avg), and 93%, 78%, and 72% using the 99.9th, 99.5th, and 99.0th percentiles, respectively; the device is described as borderline to non-compliance and precautionary measures (e.g., 50 mm distance) are recommended.

Outcomes measured

• Magnetic induction (B) near deactivator surface
• Induced in situ electric field strength (Ei) in anatomical hand model
• Compliance/exceedance relative to EU directive 2013/35/EU action levels (AL) and exposure limit values (ELV)
• Weighted peak method in time domain (WPM-TD) exposure index (EI)
• Distance recommendation for compliance (e.g., 50 mm)

Limitations

• Frequency not specified in abstract (impulse described as highly non-sinusoidal).
• Results are based on measurements near the device surface and numerical computations in anatomical hand models; real-world variability in posture/position and workplace practices is not fully described in the abstract.
• Compliance conclusions depend on chosen metric (max vs percentile averaging) and the proposed scaling technique for applying WPM-TD to Ei.

Suggested hubs

• occupational-exposure (0.95)
  Assesses cashier hand exposure and workplace compliance under EU directive 2013/35/EU.
• who-icnirp (0.6)
  Discusses implications for ICNIRP 2010 reference levels versus basic restrictions.

{
    "study_type": "exposure_assessment",
    "exposure": {
        "band": "ELF",
        "source": "occupational (EAS label magnetic deactivator device)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Cashier's hand (modeled using high-resolution anatomical hand models; workplace exposure scenario)",
    "sample_size": null,
    "outcomes": [
        "Magnetic induction (B) near deactivator surface",
        "Induced in situ electric field strength (Ei) in anatomical hand model",
        "Compliance/exceedance relative to EU directive 2013/35/EU action levels (AL) and exposure limit values (ELV)",
        "Weighted peak method in time domain (WPM-TD) exposure index (EI)",
        "Distance recommendation for compliance (e.g., 50 mm)"
    ],
    "main_findings": "Measurements near the deactivator surface found peak magnetic induction up to 97 mT (3 cm^2 probe on top of the surface), corresponding to an AL-based exposure index of 443%, which the authors describe as a conservative overestimation for induced electric field assessment. A WPM-TD-based assessment of induced electric field reported worst-case exposure indices up to 135% (using max Ei,avg), and 93%, 78%, and 72% using the 99.9th, 99.5th, and 99.0th percentiles, respectively; the device is described as borderline to non-compliance and precautionary measures (e.g., 50 mm distance) are recommended.",
    "effect_direction": "harm",
    "limitations": [
        "Frequency not specified in abstract (impulse described as highly non-sinusoidal).",
        "Results are based on measurements near the device surface and numerical computations in anatomical hand models; real-world variability in posture/position and workplace practices is not fully described in the abstract.",
        "Compliance conclusions depend on chosen metric (max vs percentile averaging) and the proposed scaling technique for applying WPM-TD to Ei."
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "electronic article surveillance",
        "EAS",
        "acousto-magnetic",
        "magnetic deactivator",
        "occupational exposure",
        "cashier",
        "non-sinusoidal magnetic field",
        "induced electric field",
        "EU directive 2013/35/EU",
        "action levels",
        "exposure limit values",
        "ICNIRP 2010",
        "weighted peak method"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.9499999999999999555910790149937383830547332763671875,
            "reason": "Assesses cashier hand exposure and workplace compliance under EU directive 2013/35/EU."
        },
        {
            "slug": "who-icnirp",
            "weight": 0.59999999999999997779553950749686919152736663818359375,
            "reason": "Discusses implications for ICNIRP 2010 reference levels versus basic restrictions."
        }
    ]
}

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