ASTM C1238-97(2021)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C1238 − 97 (Reapproved 2021)
Standard Guide for
Installation of Walk-Through Metal Detectors
This standard is issued under the fixed designation C1238; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.3 National Fire Protection Associations (NPA) Docu-
ment:
1.1 Some facilities require that personnel entering desig-
NFPA-101-1988 Life Safety Code Handbook, Chapter 28,
nated areas be screened for concealed weapons and other
Industrial Occupancy
metallic materials.Also, personnel exiting designated areas are
2.4 ANSI Standard:
often screened for metallic shielding material and other types
ANSI Z41.1-PT-1983 Class 50 and 75—For Non-ferrous
of metallic contraband. Walk-through metal detectors are
and Ferrous Safety Footwear
widely used to implement these requirements. This guide
2.5 National Institute of Law Enforcement and Criminal
describes various elements to be considered when planning to
Justice (NILECJ) Standard:
install walk-through metal detectors.
NILECJ 0601.00 Standard for Design, Performance, and
1.2 This guide is not intended to set performance levels, nor
Allowable Magnetic Field Strength
is it intended to limit or constrain operational technologies.
3. Terminology
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.1.1 continuous-wave-type metal detector—a system gen-
priate safety, health, and environmental practices and deter-
erally employing one or more pairs of closely coupled coils;
mine the applicability of regulatory limitations prior to use.
one coil is electrically energized to establish an electromag-
1.4 This international standard was developed in accor-
netic field; the other detects disturbances in that field; in
dance with internationally recognized principles on standard-
operation, the coils are configured so that the person or object
ization established in the Decision on Principles for the
being screened passes through the field; when metal passes
Development of International Standards, Guides and Recom-
through the field, the field is modified by the magnetic and
mendations issued by the World Trade Organization Technical
electrical properties of the metal; any change in the field is
Barriers to Trade (TBT) Committee.
sensedbymeasuringoneormoreofmanypossibleparameters,
including mutual inductance, power loss, phase shift, fre-
2. Referenced Documents
quency shift, permeability, etc.
2.1 NRC Document:
3.1.2 nuisance alarm—an alarm not caused by a weapon or
NUREG-1329 Entry/Exit Control At Fuel Fabrication Fa-
shielding material but by other causes such as outside interfer-
cilities Using or Possessing Formula Quantities of Strate-
ence or other operationally or environmentally induced stimu-
gic Special Nuclear Material
lus; in practice, these alarms are a nuisance because they are
2.2 U.S. Government Documents:
not obvious and must be investigated and the cause eliminated.
DOE 5632.2A Physical Protection of Special Nuclear Mate-
3.1.3 pulse-wave-type metal detectors—a system in which
rials and Vital Equipment, February 9, 1988
briefcurrentpulsesaregeneratedintransmittercoilswhenthey
DOE 5633.3 Control and Accountabilityof Nuclear
are switched on; the electromagnetic field generated by these
Materials, February 3, 1988
pulses induces eddy currents in metallic objects in the field; the
eddy currents decay when the transmitter coils are shut off; the
This guide is under the jurisdiction of ASTM Committee F12 on Security
decay of the eddy currents produces secondary voltages in the
Systems and Equipment and is the direct responsibility of Subcommittee F12.60 on
receiver coils, which are switched ononly whenthe transmitter
Controlled Access Security, Search, and Screening Equipment.
coilsareswitchedoff;thevoltagesinducedinthereceivercoils
Current edition approved Jan. 1, 2021. Published February 2021. Originally
approved in 1993. Last previous edition approved in 2012 as C1238 – 97 (2012). areprocessedandcomparedagainstabiasorbackgroundlevel.
DOI: 10.1520/C1238-97R21.
Available from U. S. Nuclear Regulatory Commission (NRC), 11555 Rockville
Pk., Rockville, MD 20852, http://www.nrc.gov. Available from National Fire Protection Association (NFPA), 1 Batterymarch
Available from U.S. Government Printing Office, Superintendent of Park, Quincy, MA 02169-7471, http://www.nfpa.org.
Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http:// Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
www.access.gpo.gov. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1238 − 97 (2021)
3.1.4 shielding—a metallic material configured as a credible 7.4 Establish where the metal-detector alarms are to be
gamma-radiation shield for special nuclear materials (SNM). transmitted and who will be responsible for alarm assessment.
3.1.5 throughput—the actual rate at which a metal detector
7.5 Provide a means for related functions such as space for
and system can screen personnel for a given application.
nearby door opening and closing, door latching, and additional
audible or visual alarms, or both, as needed to meet all safety
3.1.6 walk-through metal detector—a free-standing screen-
and security requirements.
ing device having an electromagnetic field within its portal
structure (aperture) for detecting metallic objects, including
7.6 Where it is necessary to operate metal detectors in close
some nuclear shielding materials, carried by persons walking
proximity to each other, they should be of the same manufac-
through the aperture.
turer and model so that the coils can be synchronized or
3.1.7 weapon—a device intended to do damage to personnel
operated at different frequencies in accordance with the manu-
or equipment without intentionally harming the attacker, but
facturer’s recommendations. If it is necessary to operate metal
requiring the attacker to physically activate or use the device.
detectors of different models or manufacturers, a test should be
conducted for interference before the detectors are installed.
4. Significance and Use
Where metal detectors are not compatible it may be necessary
4.1 This guide is intended for use by the designers,
to isolate the fields of each detector by as much as 20 to 30 ft.
evaluators, and users of walk-through metal detectors to be
7.7 If all electronic equipment is not designed for outdoor
installed to screen persons entering or leaving a controlled
use, provide cover and protect the equipment from the
access area. This guide is not meant to constrain design liberty
elements, especially high temperature and high humidity.
but is to be used as a guide in the selection of location and
Adequate ventilation should also be provided. Make sure the
installation of walk-through metal detectors.
metal-detector system is stable over a wide range of environ-
mentalfactors(temperature,humidity,etc.).Allmetaldetectors
5. Safety Considerations
are sensitive to changes in the surrounding electromagnetic
5.1 Warning signs should be posted if the metal detector’s
environment, and that should be the only factor affecting stable
electromagnetic field strength is of such a magnitude that
operation.
personal medical devices may be affected or damaged when
they pass through the portal. See NILECJ 0601.00.
8. Layout of the Installation Site
5.2 Local fire and safety codes should be reviewed concern-
8.1 The site layout for walk-through metal-detector instal-
ing requirements for areas selected for metal detector installa-
lation should be designed to minimize the guard force person-
tion. Metal-detector installations needing exemption from the
nel required and to avoid processing delays.The site may be in
fire and safety requirements should be approved in advance.
a new area or building, or in an existing area modified to house
6. Throughput Consideration
security screening devices.
6.1 The rate at which persons may be screened is generally
8.2 It is good practice to channel people through separate
an important factor in security applications. Metal-detector
entry and exit lanes. In areas where more extensive outbound
systemsshouldbecapableofdealingwithlargetransienttraffic
screening is required, separate lanes and equipment are even
flow such as found during shift changes.
more desirable so that equipment can be optimized for detec-
6.1.1 Throughput varies from one metal detector model to
tion of the specified objects on entry or exit.
the next. Throughput also varies from one application to the
8.3 If alarms are remotely monitored, the response tactic
next. Applications that require high-sensitivity settings will
(guard’s action, intercept corridors, lockdown schemes, etc.) to
have lower throughput.
alarmsmustbeconsideredearlyinthedesignprocesstoensure
6.1.2 Once the application specific throughput for a detector
effective and efficient interdiction.
model has been established, the number of detector lanes
required to achieve system throughput at peak times can be 8.4 Installation of equipment should be arranged to mini-
calculated. See 9.2. mize nuisance alarms from outside interference. If nuisance
alarms are too numerous, the guard force will lose confidence
7. Other Considerations
in the equipment, and security may be compromised.
7.1 Review applicable regulatory orders and policies of
8.5 Security equipment often must fit into a space-critical
appropriate regulatory agencies and facilities for information
site, but adequate space is the single greatest asset for a
pertinent to metal detector installation and operation.
security screening area. Maintaining a well-defined screening
7.2 Examine the power capability of the building electrical
area is essential so that when an alarm occurs, the security
system to ensure that it is adequate to support the metal-
ins
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