Berezansky David Pavlovich, Candidate of Technical Sciences

Metal detectors - inspection devices.
Issues of standardization of requirements.

For a wide range of readers of the magazine, a number of problems are proposed for discussion regarding the standardization of requirements for metal detectors, as one of the important types of inspection equipment. In conditions where Russian Federation There is still no State standard regulating the regulatory requirements for metal detectors as inspection devices; the issues outlined in the article are relevant.

Metal detectors play an important role in organizing the security of buildings and structures, monitoring and regulating the movement of people - detectors items prohibited from being brought into these facilities.

Metal detectors, according to the classification accepted today, belong to inspection devices that are part of integrated security equipment or used independently. Structurally, such metal detectors can be built into the barriers of access control and management systems, autonomous stationary or autonomous portable.

Items that are prohibited for visitors to bring into protected facilities and that can be detected by a metal detector (hereinafter referred to as search objects) primarily include:

Firearms;
- hand grenades;
- knives,

Selectivity also has a purely psychological significance for security workers at facilities equipped with metal detectors. From the author’s practical observations, it follows that frequent false alarms from the PLP reduce the attention of security workers to any alarm signal, including when triggered by an OP. Application metal detectors with low selectivity is most often just a reason for security staff to conduct a complete search of visitors.

Demoted from Robn. >= 0.95;
- normal with Robn. >= 0.97;
- increased from Robn. >= 0.98;
- high with Robn. >= 0.99.

The proposed values ​​were selected based on the need to ensure a sufficient level of selectivity and noise immunity, as well as taking into account the technical feasibility of these values ​​in existing metal detectors. In addition, such a division will make it possible to certify the entire variety of Russian and imported products and have a certain reserve for promising ones. metal detectors.

The most important point when assessing Robn. is the measurement technique. To create it you need:

Select a range of OPs or their simulators with specific design characteristics;
- select and justify measurement points in the controlled opening of the metal detector;
- select and justify the number of measurements based on the required confidence level;
- develop and justify measurement processing algorithms.

Second important characteristic Specifically, screening devices are selective. It also depends on the detection probability value PLP(probability of false alarm Rlt.) can be assessed in four groups:

Reduced from Rlt.<= 0,1;
- normal with Rlt.<= 0,05;
- increased from Rlt.<= 0,02;
- high from Rlt.<= 0,01

Approach to Rlt measurement techniques. may be similar to the one discussed above.

Proposed for standardization Robn. are closely related to the time spent OP in the controlled area metal detector. Therefore, the maximum speed of passing objects, at which certain probabilistic characteristics are ensured, must also be normalized. Typically, the speed of a calmly walking person is 0.5... 1.0 m/s. However, in this case, the relative speeds of movement of individual parts of his body (arms, legs), and, accordingly, the OP, can reach 1.5. 2 m/s. The methods for measuring the maximum transmission speed of an OP (or the resulting throughput) are quite obvious.

Requirements for noise immunity metal detectors in relation to external electromagnetic interference are formulated in the standard being developed)