ASTM C1238-97(R2021) pdf free download

ASTM C1238-97(R2021) pdf free download.Standard Guide for Installation of Walk-Through Metal Detectors
3. Terminology
3.1 Definitions ofTerms Specific to This Standard: 3.1.1 continuous-wave-type metal detector—a system gen- erally employing one or more pairs of closely coupled coils; one coil is electrically energized to establish an electromag- netic field; the other detects disturbances in that field; in operation, the coils are configured so that the person or object being screened passes through the field; when metal passes through the field, the field is modified by the magnetic and electrical properties of the metal; any change in the field is sensed by measuring one or more ofmany possible parameters, including mutual inductance, power loss, phase shift, fre- quency shift, permeability, etc. 3.1.2 nuisance alarm—an alarm not caused by a weapon or shielding material but by other causes such as outside interfer- ence or other operationally or environmentally induced stimu- lus; in practice, these alarms are a nuisance because they are not obvious and must be investigated and the cause eliminated. 3.1.3 pulse-wave-type metal detectors—a system in which briefcurrent pulses are generated in transmitter coils when they are switched on; the electromagnetic field generated by these pulses induces eddy currents in metallic objects in the field; the eddy currents decay when the transmitter coils are shut off; the decay of the eddy currents produces secondary voltages in the receiver coils, which are switched on only when the transmitter coils are switched off; the voltages induced in the receiver coils are processed and compared against a bias or background level.3.1.4 shielding—a metallic material configured as a credible gamma-radiation shield for special nuclear materials (SNM). 3.1.5 throughput—the actual rate at which a metal detector and system can screen personnel for a given application. 3.1.6 walk-through metal detector—a free-standing screen- ing device having an electromagnetic field within its portal structure (aperture) for detecting metallic objects, including some nuclear shielding materials, carried by persons walking through the aperture. 3.1.7 weapon—a device intended to do damage to personnel or equipment without intentionally harming the attacker, but requiring the attacker to physically activate or use the device.
4. Significance and Use
4.1 This guide is intended for use by the designers, evaluators, and users of walk-through metal detectors to be installed to screen persons entering or leaving a controlled access area. This guide is not meant to constrain design liberty but is to be used as a guide in the selection of location and installation of walk-through metal detectors.
5. Safety Considerations
5.1 Warning signs should be posted if the metal detector’s electromagnetic field strength is of such a magnitude that personal medical devices may be affected or damaged when they pass through the portal. See NILECJ 0601.00. 5.2 Local fire and safety codes should be reviewed concern- ing requirements for areas selected for metal detector installa- tion. Metal-detector installations needing exemption from the fire and safety requirements should be approved in advance.
6. Throughput Consideration
6.1 The rate at which persons may be screened is generally an important factor in security applications. Metal-detector systems should be capable ofdealing with large transient traffic flow such as found during shift changes. 6.1.1 Throughput varies from one metal detector model to the next. Throughput also varies from one application to the next. Applications that require high-sensitivity settings will have lower throughput. 6.1.2 Once the application specific throughput for a detector model has been established, the number of detector lanes required to achieve system throughput at peak times can be calculated. See 9.2.