Xray Sceener.com
 

Hand Held Metal Detectors (HHMDs)

Hand Held Metal Detectors (HHMDs), also sometimes called Metal Detection Wands, are a very common security technology - they are used at airports, seaports, public buildings, public transportation facilities, prisons, hospitals, power plants, office buildings, hotels, and casinos, among others - where these devices allow the security staff to more accurately locate the source of an alarm on a scannee’s body, often after a scannee has gone through an Archway Metal Detector (AMD) and caused an alarm.  By moving the HHMD around and close to a scannee’s body, the operator can fairly accurately locate sources of metal that may be on, or even in, the person’s body. When a suspect area is located, the HHMD will generally give off an alarm squeal. All such devices operate on variations of the same physical principle as the AMD, that is, they emit time-varying electromagnetic fields and listen for waves coming back from conducting objects. Like AMDs, HHMDs do not have the ability to discriminate between a potentially harmful metallic weapon and some benign metallic item. The responsibility of the operator of the device is to judge whether the squeal he/she heard is truly suspect, then to investigate and determine the cause of it.  The object triggering the alert may often be "innocent", for example, a wallet chain, belt buckles, watches, jewelry, shoes containing metal shanks or toes, among others. In these instances, the passenger should be directed to remove the object, which should then be submitted to visual and X-ray examination.

 

Although most HHMDs are effective screening tools, like all screening equipment they are only as good as the operator using them. Disinterested operators can render HHMDs virtually useless as screening tools. While it is not difficult to learn to use a HHMD correctly, airport managers should not underestimate the value of regular refresher training for their operators, and proper training for staff who may be called upon to serve as backup or supplemental operators.

 

The use of HHMDs requires only slightly more space than that already occupied by the operator and the scannee. Unlike AMDs, HHMDs are not sensitive to their surroundings - their sensitive zone is usually within just a few centimetres of the device’s paddle. Metal walls, elevators, fluorescent lights, and plumbing that can affect AMDs do not usually have any affect on HHMDs. A checkpoint must provide enough space for the passengers who are waiting to be scanned and an area for the actual scanning process.  It can be useful to have a table or other stable structure for passengers to lean on when they lift their shoes to be scanned. It is not recommended that scanning takes place in a private room or area. To avoid possible accusations of misconduct, or a confrontation with a passenger who does end up actually having a weapon, scanning should be performed in view of everybody else. The exception is the unusual circumstance wherein a person is suspected of hiding a weapon in a private area of their body.

 

In an environment where scannees are unfamiliar with the routine of HHMD use, accurately scanning an individual may take as much as a couple of minutes to do well, especially when there are multiple alarm sources on one person, e.g. belt buckle and steel shanks in boots. However, most passengers that are frequent fliers have probably been screened by HHMDs before, and so they will be generally cooperative and anxious to get through the metal detection process quickly.  It may take no more than about 30 seconds to scan such individuals with a HHMD.  In some airports, passengers are offered a choice of screening environments.  Frequent travellers, known as "expert" travellers can elect to join a screening line marked by a black diamond sign. Less experienced "casual" travellers can elect to use a special screening line with a blue sign where they can take more time and avoid feeling pressurised; and families, groups and those with special needs can use a very leisurely screening line designated by a green sign.

 

Most HHMDs should be set at their highest sensitivity. You should periodically run the hand-held detector across some piece of conductive material, so the ensuing squeal of the detector can assure you that the device is operating properly.

 

If the person you are about to scan caused an alarm when walking through a AMD, and your job is to try to locate the source of that alarm on his or her body with a HHMD, do not stop the complete scanning process just because you come across one alarm-causing item. Continue the scan.

 

The detector should be passed over the scannee’s body at a distance of no more than a few centimetres. Avoid touching the body or clothing with the detector. However, for some baggier clothing, such as pants or jackets, it may be necessary to hold the detector against or more into the fabric while scanning in order to stay within a few centimetres of all body surfaces.

 

The body scan should be performed each time in the same pattern so that the operator always knows what parts of the body still need scanning. A sample routine follows:

 

·        Ask the scannee to stand with his or her feet about 50cm apart.  Footprints outlined on the floor or drawn on a mat can greatly help position the scannee properly. Ask the scannee to hold his or her arms out to the sides, parallel to the floor.

·        Start at the top of one shoulder of the scannee. With the paddle of the detector held horizontally and parallel to the front of the body, sweep down one side of the front of the torso, down the leg to the ankle, then move to the other ankle and sweep back up the front of this opposite leg and torso, ending with the opposite shoulder. (If a particular HHMD’s detection paddle is less than half the width of the average body, or if a particular body is wider than twice the width of the detection paddle, the pattern will have to be modified to achieve adequate coverage.

·        Sweep the HHMD over the outside top of the arm from the top of the shoulder to the bottom of the wrist, then up the inside of the arm to the armpit. Sweep down that side of the body to the ankle, then up the inside of that leg and down the inside of the opposite leg, then back up the other leg from the ankle to the underarm. Repeat the sweep of the inside and outside of this arm. Note that it is particularly important to avoid touching the HHMD up against the scannee’s body when scanning up and down between the legs.

·        Ask the scannee to turn around. (Arms can be put down now.) The pattern used to scan the front of the body should now be repeated over the back of the body.

·        Ask the scannee to grab the edge of a table for support, then to lift one foot up in back of himself/herself. Scan across the bottom of the shoe. Repeat for the other foot. The operator should expect to hear a short squeal from the HHMD when scanning the bottom of shoes or boots with steel shanks or steel toes. Both shoes should cause equivalent squeals.

·        For the head area, start at the top of the forehead and scan around the top of the head down to the back of the neck.

 

Given that the type of HHMD being used is the kind that provides different volumes of feedback, i.e. a soft squeal versus a much louder squeal, the operator will be able to distinguish between the detection of a smaller innocuous item or material, such as a zipper, and the detection of a larger, more suspicious item. It is important to be attuned to these different volumes to recognise when further investigation is required for a particular scannee.

 

When the HHMD identifies a suspicious item and there is no visible source for the alarm (clothing is shielding the source object), ask the person to show you what they have in that area. For example, for an alarm along the arm or wrist, have the scannee pull up his or her shirt sleeve. Using your detector, duplicate the squeal you heard before, but now over the visible item. Do not let the scannee influence you as to what is actually causing an alarm. For instance, if the detector denotes the presence of a suspicious item under a shirt sleeve, do not fail to completely investigate the source of the alarm even though the scannee assures you that it is just his/her wristwatch. Because this passenger has triggered an alert, he/she must not be able to exit the checkpoint without the source of the alarm being verifiably resolved. 

 

The lower abdominal area is particularly difficult to scan because this area is private in nature and because of the metal items usually found in this area: belt buckles, metal buttons or snaps, and metal zippers. When doing the initial front body scan, if an alarm occurs in this area, there are two possible ways to further investigate:

 

a) Ask the scannee to undo any belt he/she might have on and have him/her pull the belt ends away from the middle of the body. Now scan the zipper area; the feedback volume from your HHMD should tell you if it is now only sensing a zipper and/or a metal snap, or if a more suspicious item is present and further investigation is needed.

 

b) A second approach that some facilities use is that, if the lower abdominal area is causing an alarm on the HHMD, ask the scannee to bend the front of his or her front waistband forward, to ascertain that no weapon is hidden behind it. Facilities need to be available for situations where further investigation can be accomplished privately, but only in the presence of two or more staff members who are the same gender as the scannee.

 

The checkpoint should be designed to facilitate the control of passengers and eliminate the risk of a passenger bypassing the screening procedures; it should be designed to facilitate the different passenger volumes resulting from the varying number of flights being processed at any one time, with the minimum of disruption to operations; it should be equipped with walk-through metal detectors, X-ray equipment and other explosive trace detection equipment to expedite the processing of passengers and cabin baggage.

 

In many facilities, the misconception exists that someone known by the screener, such as a fellow employee or other security personnel, should be allowed to circumvent the security screening system. It must be clearly established that in order to ensure the integrity of any security screening process, everyone must be subjected to the screening requirements, including passengers, airport employees, contractors, air crew, and security personnel.

 

 

 

 

 

*The information about HHMDs is provided here as a guidance only to compliment and not to replace procedures and guidelines used at your own locality/facility.

 

PrintTell a friend
Web Design