Why two-way radios make the perfect safety device
24 June 2019
Intrinsically safe professional mobile radios not only provide highly efficient, instant group communications for industries working with hazardous materials, but also offer multiple safety applications for workers and added-value SCADA capabilities. In this article, Matthew Napier of Hytera Communications (UK) looks at the many benefits and capabilities of explosion-protected two-way radios.
Safety is of paramount importance for industries dealing with hazardous materials, including potentially explosive liquids, gases and dusts. Hazardous environments are found in the oil & gas, petrochemical, pharmaceutical, mining/extractive, nuclear, chemical and some manufacturing operations. Others sectors such as ports and airports contain potentially dangerous fuel storage facilities.
These types of businesses operate, or at least should operate, under highly regulated conditions designed to protect workers, the wider population, the environment and the facilities themselves from exposure to harmful spills, leaks and explosions.
It is essential that equipment used does not provide an ignition source such as a spark that might cause an explosion. Electronic equipment must be ‘intrinsically safe’ (IS) and should meet the International Electrotechnical Commission for explosive atmospheres (IECEx) equipment standard and the European ATEX (Appareils destinés à être utilisés en ATmosphères EXplosibles) directives.
Communication devices are no exception and therefore need to be designed to avoid heat generation or the creation of sparks. Standard radios or cellular phones are not safe to use for this reason, but a number of two-way radio manufacturers offer intrinsically safe Professional Mobile Radio (PMR), also known as Land Mobile Radio (LMR), terminals and infrastructure based on standards such as TETRA and DMR.
Robust and reliable
The radio is the worker’s lifeline, so it must be capable of operating in the most extreme conditions. Radios need to come with a high IP rating certifying their ability to resist ingress by sand, dust (including metal dust), oil/fuel, chemicals and water. They must be tested for resistance to thermal shock (the ability to withstand sudden changes in temperature) and be able to operate in temperatures ranging from -30°C to +60°C.
They should be tested for thermal cycling (the effects of alternating heat and cold) to ensure their reliability and be rugged enough to withstand hits and drops measured according to the US Military Standard (MIL-STD) and not create a spark if the radio or its battery are dropped.
Radios should feature an ergonomic design that makes them simple to use in hazardous or extreme environments, including easy operation with gloves or helmets/visors. Loud and clear voice communications are essential, so it is worth choosing radio terminals that feature extraneous noise cancelling technology.
It is also important to ensure that the correct accessories are used including high-attenuation headsets, throat and skull microphones - all useful for hands free operation, as well as clips and belt fastenings that will not cause a spark. All accessories must be tested and approved as complete systems to ensure safety is not compromised within an intrinsically safe environment.
PMR systems have a number of advantages for industries where communication systems are critical to the smooth and safe running of operations. PMR systems provide private communication networks, which enable coverage, capacity, resilience, security and levels of availability to be exactly tailored to the needs of the business.
Relying on cellular mobile phone networks can be problematic as geographic coverage is dictated by the commercial needs of the operator’s business. Many of the industries cited above have sites in remote locations where cellular coverage can be patchy or even non-existent, so a private PMR network is often the only reliable solution.
PMR networks offer the best mission critical voice and messaging applications available, including group calling, individual calling, broadcast calling, emergency calling and even full duplex (telephony) with very fast call setup times of under 300ms utilising push-to-talk (PTT) technology.
Group calling provides a highly efficient way of communicating information to many people simultaneously, which can be of vital importance in an emergency. PMR systems also enable calls or messages to be prioritised according to the needs of the business.
Types of call (such as emergency calls) can be prioritised to have primary access to the network, as can particular call groups or individuals. Lesser priority calls and messages will be queued and get access to the network as channels become available.
A PMR radio should also been seen as a, if not the, primary safety device for workers. Aside from instant PTT voice, almost all radios come with an emergency button, which will send an alert with the highest priority to the control room, along with the worker’s location.
Over the air programming (OTAP) can be utilised by the control room to remotely manage and control the software and configurations on the radios, including the ability to send automated alerts and messages. It is also easy to customise applications to suit individual businesses and industry sectors. They can, for example, support job ticketing and workflow management software.
The radios can be used to receive and activate alarms and to shutdown equipment if connected to remote terminal units (RTUs) without the need to send any staff, saving time and potentially keeping personnel out of harm's way.
Man Down alarms will trigger an automatic alert if the radio’s tilt sensor passes a certain angle and remains there beyond a pre-set time. Lone Worker alarms also send immediate automatic alerts based on tilt sensors. If the worker does not check back in with controllers within a pre-set time the control room is alerted again.
Integrated GPS provides location-based applications, so if any of the above alerts is triggered, controllers will know exactly where the worker is and be able to coordinate a rescue response more quickly.
More generally, GPS enables workers to be tracked and monitored, so managers know where everyone is at any one time. If there is an accident or an emergency this makes it easier to locate the most appropriate people to respond to the incident - be it first aiders or fire marshals.
GPS technology can also be used to set geofences. The radio will trigger an alert if unauthorised personnel attempt to access a restricted area, or there is unauthorised movement of tagged equipment. Personnel can also receive an alert on their radio warning them if they come near danger zones.
Most modern digital radios support Bluetooth and other technologies for near field communication (NFC) applications. As GPS does not work well indoors, Bluetooth location beacons can be deployed to track the whereabouts of staff inside buildings, basements, tunnels and the like.
They can be used to identify employees clocking in and out of work or entering certain areas. They can also provide an audit trail for security guard patrols or inspection regimes by maintenance and equipment staff proving who was where, when.
Bio harnesses measuring personal vital body signs such as abnormal temperature, blood pressure and heart rate can also be integrated via Bluetooth. The data is transmitted to the radio and then sent on to the control room. Supervisors can then be more proactive and warn workers of possible health issues.
PMR terminals can also pick up information from either Bluetooth-enabled fixed or portable gas detector sensors. Managers can analyse the data to see what is in the atmosphere in real time and work out a worker’s exposure to toxic gases over time. This may help to prevent diseases caused by exposure to hazardous materials later in life.
Another advantage of deploying digital PMR solutions is that the network can also carry IoT (Internet of Things) and SCADA (supervisory control and data acquisition) data. The amount of data involved is quite small and can easily be transmitted from RTUs via narrowband PMR technology.
Remote monitoring of equipment provides much greater visibility of operations to enable proactive management of critical assets. If something goes wrong it is much easier to identify what has failed, where the unit is located, and potentially some immediate diagnostics as to why it has failed.
Early warning of possible equipment failure enables planned preventative maintenance regimes, saving time and money as expensive shutdowns are avoided. The time and opex cost of manual inspections and maintenance is reduced, thereby boosting operational efficiency.
A wide range of equipment can be monitored in this way from drilling well heads, storage tanks, pipelines, petrochemical units, electricity substations and distribution grids. Parameters such as flow, pressure, vibration, temperature and electricity network loads can be controlled and field production processes automated, including remote equipment shutdown and recovery, in distant locations from a single central point.
IoT/SCADA can also be used for environmental monitoring to provide compliance with regulatory regimes and to provide fast alerts of any spillages or leaks of toxic liquids or gases. This helps to reduce the number of incidents and exposure to liability and potentially expensive fines in the event of environmental damage.
Finally, it is worth noting that modern digital two-way radio systems can in integrated with other communication technologies, including back office IT systems, fixed telephony networks, cellular mobile phone systems, CCTV monitoring systems, body-worn and vehicle-mounted cameras and, as already indicated, IoT/SCADA networks.
The latest unified communications connectivity platforms integrate all these data sources and communication systems into a single stack of information and services, which can be displayed visually using modern control room dispatch systems. PMR systems also offer advanced encryption for extra security, as many operations will be transmitting sensitive business information.
A robust, reliable communications system lies at the core of efficient and safe business operations. As well as being a vital safety tool for workers, having reliable group communications everywhere can also improve the efficiency and productivity of the workforce.
About the author
Matthew Napier is Sales Director at Hytera Communications Corporation (UK) Ltd. and is responsible for Hytera’s sales operations in the UK, France and the Nordic countries. With over 20 years’ experience in the two-way radio and communications industry in various account management and sales roles, he has a wealth of experience and expertise specifying radio systems across a variety of industries in the private and public sector.
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