Mobile Workers in hazardous areas: solutions for workers in process plants

Greater need for documentation, smaller workforce: workers in process plants are faced with constantly increasing demands. At the same time, the security requirements are also on the increase. Digital tools can help to meet these, but only with the right overall concept.

Systems in the process industry can be compared to enormous organisms: their connecting lines are pulsing with a great variety of substances. Pumps and compressors generate the heartbeat, tanks and pipelines ensure the supply. The original substances are "digested" in reactors and other machinery, where they are turned into value-added products. And just like biological organisms, processing plants also undergo constant monitoring and repairs. The processes carried out in the body by nerves, enzymes, phagocytes and other biological mechanisms are the responsibility of specially trained staff in plants: reading process parameters and measuring instruments, taking samples, visually inspecting system components for damage and, if necessary, carrying out repairs. Of course, staff also have to document the results of this inspection and maintenance work.

In the oil and gas, (petro) chemical and pharmaceutical industries, this is subject to very specific regulations. Here, hazardous chemicals and toxic gases are circulating in the lines and containers, frequently under high pressure. Add to that the mechanical and electric hazards of movable machinery, and elevated work entailing the risk of falls. But above all there is the explosion hazard, since most machinery and system components are located in areas that are briefly or constantly exposed to explosive atmospheres, which means that work in such environments is subject to very strict rules. In addition to protective equipment for the workers and explosion protection for the system components on site, there are also further workplace safety measures such as preparation for emergencies. This includes emergency plans and drills as well as the communication with the on-site workers.

A trend that has been emerging during the last few years is the increasing amount of documentation required for inspection results and repair measures. At the same time, the increasing shortage of skilled labour also affects maintenance and system operation, requiring operators to look for solutions. These include for example the application of digital aids to help mobile workers to not only become more efficient, but also work more safely. Frequently, this entails the purchase of tablet computers and smartphones to replace the inefficient and error-prone recording of information with pen and paper to be subsequently transferred to computer systems. Also, these kinds of tools enable workers to access instructions and videos on-site to help them, for example, repair machinery and other system components efficiently. In the future, machines will be fitted with digital type plates, with which the required operating or repair instructions can be directly accessed at the machine, without the need for lengthy research. Video communication and augmented reality solutions can be used to connect with experts on site.

An important aspect is the safety of mobile workers when they are in field, at large factory premises and sites, and in areas of increased hazard (lone worker protection). Be it emergency alarms, dead-man monitoring or localisation of workers in real-time: even complex case scenarios can be handled with adapted every-day devices – for example an explosion-protected smartwatch.

Frequently, however, the solutions in use at processing plants are something of a piecemeal approach, for example tablets that are initially only purchased for dedicated maintenance tasks, or smartphones that can in theory do everything, but due to their size cannot be operated with gloved fingers or only one hand. In practice, mobile worker projects frequently fail because solutions were selected without consulting the local workforce, and without taking into account the actual application scenario on site. Aspects such as reparability, technical support for the devices and the update policy of the providers of the operating systems and softwares play a much greater role in the rough industrial environment than for private use: will the battery last for entire shift? Can the battery be replaced or must the device be scrapped at the end of the battery life cycle? Do the update strategies for the operating system and the apps match? After all, workplace safety and maintenance and documentation are usually handled by different, special applications. Considerations concerning the selection and design of network technology play an important role here. Without due care, the system is bound to be frustrating for the users.

At R. STAHL, such projects are handled by a team of experts in the field of system solutions for automation in hazardous areas: these specialists not only analyse the actual application scenarios and the work environments of the mobile workers, but are also familiar with the technical challenges and obstacles. The ideal solution will always feature a combination of mobile devices and the right network infrastructure: which wireless network is most suitable? What are the benefits and drawbacks of Wi-Fi, LTE or 5G for cramped or spacious sites? How future-proof are the devices, operating systems and the IT infrastructure in general?

The actual application also plays a major role when choosing the network technology, because a mobile application won't work without a network. The monitoring and localisation of workers for the purposes of workplace safety requires only a small volume of data, meaning the transfer technology only needs a small bandwidth. However, since the safety of the workforce is at stake, the network must be available non-stop. In contrast, applications for inspection, maintenance and documentation require substantially higher bandwidths, but their availability is not time-critical.

In the foreseeable future, WiFi6 and 5G are expected to prevail for processing plants out of the large variety of network technologies – here too, the choice depends on local conditions and intended applications: WiFi is generally used indoors or in selected outdoor areas, and is based on familiar IT technology. Licence-free frequency bands (ISM bands) are used, and there may be interference with other applications using these bands. The 5G mobile network standard consists of public and private networks. If the company premises have sufficient signal coverage you can use the public networks of the mobile network operators. While this means there is no need to develop your own infrastructure, using public networks entails substantial monthly costs. Also, the use of public networks gives rise to questions concerning data ownership and resource prioritization in the case of capacity overload. 

The 5G cellular network standard can also be used for operating a private network on company premises. Whilst there are investment costs to be considered for the initial infrastructure, you can customise the network to meet your own requirements. This version also has running costs for the licence, but these are manageable. Both public and private 5G networks are ideal for covering large production areas such as those prevalent in the process industry. Also, WiFi and mobile communications can complement one another extremely well under certain conditions.

In any case, the base stations covering plants with hazardous areas also have to meet explosion-protection requirements. R. STAHL can provide sophisticated enclosure systems for the design of a network infrastructure that allow the use of any type of radio application.

For the "inspection and maintenance" application described earlier, both WiFi and 5G are equally suitable. Due to its greater signal coverage, 5G is the better solution for the "workplace safety" application.

Choosing the best possible solution, and designing WiFi and 5G networks in process plants and in hazardous areas is complicated and should be tailored to the needs of the intended application. Because mobile workers move around the plant, the network must be designed with a seamless handoff between cells in mind.