At ZoneSafe, we understand the constant challenge of managing busy industrial sites. The underlying risk, from warehouses bustling with activity to harsh environments in quarries and waste sites, is always focused on the people-plant interface, where there is potential for collisions.
The “people-plant interface” refers to the intersection where people and machinery (plant) operate in the same vicinity. Our proximity warning systems reduce this risk by establishing robust detection of personnel and machinery and initiating instant alerts.
The ZoneSafe system operates with several core components, allowing us to create a 360° detection zone around vehicles, and alert workers and operators. We offer two highly effective solutions: Tag-Based (RFID) and Non-Tag (UWB). While each has its strengths and weaknesses depending on the application, both are incredibly robust for integrating both indoors and outdoors, with highly detectable alerts even in poorly lit or harsh conditions.
This article outlines the specific benefits and limitations of each system, enabling you to clearly see how ZoneSafe can best help you secure your site.
Tag-Based Proximity System: Two-Way Warning at the People-Plant Interface
This solution’s strength lies specifically in its two-way warning capability.
At its core, the system utilises a vehicle-mounted sensor that creates a 360-degree detection zone around the machine. This sensor is specifically engineered to detect the small, active RFID proximity tags worn by the worker. This RFID technology does not rely upon line of sight, which is particularly beneficial at blind corners and blind spots where pedestrians may be hidden. Detection range can be configured up to 10 metres, providing ample time for both pedestrians and vehicles to react at the people-plant interface.
When a pedestrian is detected within the danger zone, even if they are invisible behind obstructions, the system triggers a two-way warning. The tag vibrates to alert the worker, while the driver is alerted by an audible alarm and flashing visual warning on a control panel inside the vehicle. The pedestrian worker receives a prominent and persistent warning via haptic feedback (vibration) from the tag, enhancing situational awareness. The driver is also given a tag, which is entered into the control unit before they start the vehicle. Whilst the tag is in the control unit, it cannot be detected. However, if the driver leaves the vehicle, they take their tag to ensure they will be detected by other moving vehicles.
Non-Tag Visual Warning System: Infrastructure Alerts at the People-Plant Interface
This solution relies on a fixed infrastructure sensor detecting the active signal from oncoming vehicles (which are equipped with the standard vehicle-mounted sensor). This system typically utilises Ultra-Wideband (UWB) technology to achieve 360-degree detection with a long range of up to 50 metres. Crucially, this detection is line-of-sight. This signal then activates a visual alert for pedestrians operating within this shared space via a flashing warning sign, beacon, traffic light, or projection.
The visual warning system differs from the tag-based system in that the activated alert does not directly warn the pedestrian via a tag, but rather provides a flashing warning, sound alert, projection, or combination to everyone in the surrounding area that a vehicle is nearby. This solution is particularly advantageous as it is effective in the loudest working environments, where forklifts have other alarms, and an audible warning could be missed at the people-plant interface.
Choosing the Right System: Application-Specific Advantages
While both solutions are robust for integrating both indoor and outdoor environments, the critical need for one over the other depends on the specific operational requirements. Below, we list a few examples; however, to gain a deeper understanding of the technologies, we’ve devised another helpful resource that compares UWB with RFID for proximity warning.
Managing Nuisance Alarms in Narrow Spaces
In environments like a typical small warehouse with narrow aisles, the Tag-Based system’s strength – its non-line-of-sight RFID detection—may become its disadvantage. Tags can be detected behind racking, which could trigger multiple nuisance alarms when there is no real immediate danger. In these cases, the Non-Tag Visual Warning System is the ideal application. An infrastructure sensor and active warning sign, fitted at the end of an aisle, provide a clear and sufficient visual warning to pedestrians up to 50m away of an approaching forklift, effectively eliminating the risk of unnecessary alerts.*
*It’s worth noting that we have developed a masking box that can be set up in high-risk people-plant interface areas, should you want to fit a tag-based solution. Always ensure a full site survey is carried out to determine the right solution for you.
Maximising Protection in Large Areas
In a larger warehouse with wider open spaces, the Tag-Based system becomes far more reliable and essential. Not only does the risk of nuisance alarms diminish, but it also provides an added layer of two-way protection where pedestrians and vehicles are likely to come into close proximity. It is in these environments, where anything from pallets to other vehicles can obstruct the driver’s view, that an instant, recurring alert delivered directly to both the operator and pedestrian ensures that risk is mitigated as soon as the boundary has been crossed.
Overcoming Scale and Obstruction in Extreme Environments
For large-scale, remote operations, such as a vast quarry, the Tag-Based system delivers timely and effective warnings. The Non-Tag system is often impractical here; the scale of the site makes infrastructure installation insufficient, and multiple blind spots created by heavy plant and large machinery can weaken a visual signal or make it a distraction, due to its line-of-sight requirement. This environment demands the highest level of safety, where the Tag-Based system’s immediate, two-way alert ensures a worker lurking “in the wilderness” is safely detected and warned.
Considering Cost and Scalability
Another key application factor is workforce size and access. For bigger sites with hundreds of workers, visitors, and contractors, allocating tags to all personnel can prove costly. The Non-Tag system offers a clear benefit for scalability, requiring only vehicle and infrastructure components to protect the general population in a danger zone. Businesses may decide to prioritise the biggest risk first, or limit tags to core personnel. It’s worth noting that tags can be used as part of an access control system, therefore, only allowing a “tag holder” into dangerous vehicle manoeuvring areas. This may help to resolve excessive tag quantities and costs.
Our Expertise: Tailored Solutions and Future-Proofing
Fortunately, we have over 15 years’ experience engineering tailored solutions. The decision doesn’t have to be binary. Many customers begin with a single solution focused on the biggest risk and then expand to a modular proximity warning system as their budget and needs evolve.
Our solutions are designed to complement your existing safety measures, including personnel training, by actively reinforcing your primary control measures of physical segregation and traffic management plans.
Just getting started can make a significant difference by lowering the risk of collisions at the people-plant interface, subsequently mitigating financial and human costs for your business.
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