Stainless Steel And Airport Security: A Traveler's Concern

Metal detectors at airports are designed to identify a wide range of metal objects to ensure passenger safety. Stainless steel is commonly used in orthopedic implants, and these metal detectors are sensitive enough to detect such implants. While the detectors can be adjusted for sensitivity, they are likely to pick up on stainless steel, and those with implants may face more invasive security checks.

Orthopaedic implants and stainless steel

Stainless steel has been used extensively in the manufacturing of orthopedic implants, with stainless steel plating systems being used for decades for fracture stabilization. Stainless steel is one of the earliest modern implant materials to be widely employed due to its durability, strength, and wide availability. It is frequently used in the manufacturing of orthopedic plates, screws, sliding hip screws, flexible nails, and early-generation rigid intramedullary nails.

However, stainless steel has a higher modulus of elasticity than titanium, which is more similar to bone. This mechanical incompatibility causes implants to be structurally stiffer than bones, and so titanium is often preferred for implants. Additionally, stainless steel alloys often contain nickel, which can cause allergic reactions in some patients.

Despite these drawbacks, stainless steel remains a common material for orthopedic implants due to its desirable structural properties, biocompatibility, and proven success in load-bearing and fixation. The early life of orthopedic-destined stainless steel, including development, manufacturing, and implantation, is well-understood, cataloged, and regulated. However, the fate of these implants after removal is less clear, with some uncertainty surrounding their post-vivo disposal, incineration, or patient ownership.

Regarding airport security, stainless steel items such as jewelry or implants are unlikely to set off metal detectors. Metal detectors at airports are designed to detect weapons, so they will typically only be triggered by metal objects above a certain weight or density threshold. Higher-quality stainless steel is also non-magnetic, which further reduces the likelihood of setting off metal detectors.

Inconsistent security checks

Metal detectors at airports are designed to identify a broad range of metal objects, from weapons to small items like car keys. Stainless steel, a commonly used implant material, is easily detected due to its magnetic properties. However, the sensitivity of these detectors can be adjusted, and some airports may have machines set to different levels, impacting consistency.

Travellers with metal implants, such as joint replacements or metal plates, often face more invasive security checks and longer processing times. In some cases, individuals may be required to show their scars or undergo additional screening, such as a full-body scan or a targeted hand search. The lack of specific regulations for screening individuals with implants adds to the inconsistency.

To address this issue, experts have proposed the creation of a universally recognised implant identification card. This card would streamline security checks and improve the travel experience for those with implants. In the absence of standardised regulations, travellers with metal implants are advised to be patient and allow extra time at the airport to navigate security screenings.

While heightened security measures protect all passengers, the inconsistent application of procedures can cause frustration and delays for those with metal implants. Standardised guidelines and the adoption of accredited implant identification could alleviate these issues, ensuring fair and efficient security checks for all travellers.

Metal detector technology

Metal detectors have been a common feature of airports for some time, and they are now more advanced than ever. They are a crucial component of airport security, acting as the first line of defence in high-risk environments. They are necessary to prevent prohibited items from compromising security and to identify hidden weapons and other hazards.

Almost all airport metal detectors are based on pulse induction (PI). This technology uses a coil of wire on one side of the arch as both the transmitter and receiver. Short bursts of current are sent through the coil, generating a magnetic field. When the pulse ends, the magnetic field collapses, creating a sharp electrical spike and another current, known as the reflected pulse. This process is repeated, and if a metal object is present, it creates an opposite magnetic field. This magnetic field adds its "echo" to the reflected pulse, making it last slightly longer than it would without the metal object.

A sampling circuit monitors the length of the reflected pulse and compares it to the expected length. If there is a discrepancy, the circuit sends a signal to an integrator, which amplifies and converts the signal to direct current (DC). The DC's voltage is then changed into a tone, alerting the metal detector that a metal object has been found.

Handheld metal detectors are also used for more targeted and detailed inspections. These devices can differentiate between harmless items, such as cell phones or belt buckles, and potential threats like firearms or knives. This technology is based on the same PI technology as the walk-through detectors but offers greater precision and versatility.

Recent advancements in metal detection technology have improved the sensitivity, speed, and accuracy of these devices, making the airport security screening process more effective and less intrusive.

Salt water and body fluids

While there are no specific regulations, standard advice suggests that metallic implants will likely trigger walk-through metal detectors, resulting in a hand search with handheld devices. Security scanners will likely identify anomalies, requiring further targeted searches.

It is recommended that individuals with metal implants inform TSA officers and prepare for additional screening. A study found that implant identification cards can expedite security checks, suggesting the potential benefit of a universally recognized accredited implant ID card or biometrically chipped ePassports that include medical information.

Now, regarding saltwater and body fluids, it is important to note that they are not mentioned in the context of airport metal detectors and their interaction with the human body. However, saltwater and body fluids can affect metal detection in other contexts, such as underwater metal detecting.

In the case of underwater metal detecting, the primary concern with salt water is maintaining the equipment's integrity. Waterproof metal detectors are available, but it's crucial to ensure that the battery compartment is sealed to prevent water leakage. Additionally, using a beach scoop can aid in retrieving targets underwater without disturbing the surrounding sand or silt.

While body fluids are not directly related to metal detection, it is worth mentioning that swimming in any body of water can lead to "swimmer's itch," caused by parasites, resulting in skin irritation. However, this is not specifically related to the interaction between body fluids and metal detectors.

Tips for seamless security checks

Metal detectors at airports are designed to detect weapons, so they will typically only go off if they detect metal over a certain amount of weight. Smaller items like jewellery are usually fine to pass through in, but it depends on the size and density of the metal.

• Check security wait times at the airport in advance using apps like JetHub and MyTSA. This will help you make a better-informed decision on when to arrive.
• Flying first or business class can grant you priority access to expedited security checkpoint lines at some airports.
• Ensure that coins, lighters, and other small items are placed inside a bag and not loose in trays.
• Place any liquid toiletries in clear plastic bags, and make sure they are easily accessible at the top of your bag or in the side pockets.
• Place your tickets and identification in an easy-to-reach spot so you can quickly grab them in the security line.
• If you don't have TSA PreCheck, put any carry-on food into a clear plastic bag and then into a bin. Food items often trigger alarms during the screening process, and this will lessen the likelihood that an officer will need to open your bag for closer inspection.
• If you have a lot of liquids or large electronics, consider enrolling in a Trusted Traveler Program like TSA PreCheck or Global Entry to speed through security without removing these items from your luggage.

Frequently asked questions