Challenges and opportunities of Hazardous Area communications
10 September 2014
It has long been recognised that establishing effective data communication systems within process industry and high hazard plants is usually a complex, and therefore expensive, process. In this article, Extronics Marketing Manager Ross Tye looks at some of the issues surrounding hazardous area communications and suggests some solutions.
Many sites such as large petrochemical and chemical plants are legacy sites and predate the PC-led IT revolution of the late 20th century and were not equipped with data cabling. On this type of plant, it is hugely expensive to retrofit wired network systems, for example with copper based Ethernet.
Wireless systems at first glance would seem to offer a solution but the process industry’s extreme environments pose more than a few problems for wireless network functionality. The heavy metal environment due to vessels and pipes causes RF multi-path where the signals bounce off different surfaces and arrive at the receiver at different times. In some cases this could render a network totally inoperable, but certainly significantly reduce bandwidth or connectivity. This meant that a disproportionate amount of access points needed to be deployed to give adequate coverage when compared to office environments. Add this to the physical size of many sites and the costs quickly become prohibitive.
All these issues and costs are compounded where the area is deemed to be hazardous.
While wired networks can support high data rates with high reliability, it is not always feasible or cost-effective to dig trenches or string overhead wire across chemical plants, LNG terminals or off-shore oil platforms. Manufacturing plants and storage facilities with explosive atmospheres and ignition hazards have to conform to the safety standards applicable e.g. ATEX or IECEx , raising the installation cost and complexity of networks. Consequently many deployments utilise both wired and wireless technologies, often combining licensed and unlicensed spectrum across a number of different frequencies. An added issue was the relative scarcity of product and solutions suitable for installation in hazardous areas.
The two major problems for any manufacturer wishing to develop products and solutions which specifically address hazardous areas in general are the relatively limited size of the market and the lack of a widely accepted international safety standard. Hazardous areas account for a relatively small proportion of the global industrial market with a recent estimate being c$4billion – a tiny fraction compared to the overall size. This means that for products to stand any chance of making a return they have to be marketed on a global basis. This is where the second problem raises its head. Despite the laudable efforts of IECEx to introduce a set of standards accepted world wide, there still exists a whole raft of national standards. For example anyone developing products aimed at the oil and gas market globally must obtain authorisation to many standards e.g. ATEX (Europe), Inmetro (Brazil), Class 1 Div (USA) Class 1 Zone 1 (Canada) IECEx (Australia) GOST-R (Russia) GOST-K (Kazakhstan). This is both time consuming and prohibitively expensive.
The upshot of this is that only a limited proportion of the products available in non-Ex areas are actually available for hazardous areas. A good example of this is antennas. The performance of wireless installations is highly dependant on the antennas used and many powerful antennas are available for non-ex deployment e.g. omni – directional, planar, panel directional, low profile, dual band etc. This means that the coverage from each access point can be maximised and this keeps the number of points deployed, and therefore the cost, to a minimum. In the Ex arena the antenna options available are extremely limited and expensive, primarily as a result of the cost issues outlined above. Without the flexibility of antenna choice, Ex access point deployment has tended to be at greater density than non-Ex, with a consequential increase in costs.
Therefore, until recently, a hybrid patchwork of communication technologies was the best achievable solution. However for mobile, data-intensive clients such as rugged handheld terminals and vehicle-mounted terminals the final results fell short of both IT requirements and user expectations. Wireless signal quality and available bandwidth was often highly variable across an industrial or outdoor site, resulting in user complaints.
Many people felt that WiFi networks based on the 802.11 set of standards offered a clear solution to the issues described above. The prevalence of WiFi at home, office, whilst shopping etc has raised expectation levels as to what to expect from data communications. We are all getting used to having high speed internet and reaping the benefits of the myriad number and type of applications available. Two recent developments have certainly pushed the hazardous area market in the direction of WiFi. Firstly the introduction of MIMO enabled Access Points based on the 802.11n standard has dramatically improved wireless performance in heavy industrial environments with high levels of metals and liquids present. Previously, WiFi links were particularly affected by multipath interference created by the abundance of metallic structures causing the signal to scatter before arrival. In contrast, MIMO uses multipath algorithms to increase the range, throughput and robustness of the data link by capturing the scattered signals and recompiling them. This has lead to dramatic performance improvements and meant much more cost-effective WiFi deployments.
The second important breakthrough is the development of an intrinsically safe RF galvanic isolator. Effectively this makes all RF outputs protected by intrinsic safety and blocks all known fault i.e AC, DC & Hazardous Transients. This enables the use of standard RF equipment and greatly simplifies both the certification and installation of wireless data networks. This means that any standard antenna can now be deployed in a hazardous area if the RF is protected by one of these isolators. As a result significant performance gains can be created using the most appropriate antenna for the installation. The fact that these more powerful antennas are often a fraction of the cost of Ex d or Ex e antennas is an obvious additional benefit.
As a result of these important developments a number of significant applications are able to be effectively deployed and many companies in petrochemicals and oil & gas exploration are actively investigating them. Additionally the new generation of smart mobile devices, including phones and tablets, are being developed to meet intrinsic safety standards. The ability to develop low cost apps will provide a further boost to the uptake of hazardous area wireless. A couple of key areas where rapid development is taken place are here as examples.
Key Application – RFID Asset Tracking
Asset tracking by RFID is well established in the retail and manufacturing sectors and now the oil and gas sector is responding to heightened costs in exploration and production looking to improve the cost-effectiveness of all its operations. Due to the high cost of tracking and transporting assets across remote exploration sites, companies in the oil and gas industry are overstocking assets to minimize downtime and delays at work sites. Overstocking work sites is extremely expensive and companies are searching for a cost effective solution to manage asset allocation and thereby reduce the need to overstock expensive equipment. Safety inspection and maintenance is another area where RFID is gaining a real foothold in hazardous areas through innovative developments. For example the new smartphones mentioned earlier coupled with small Bluetooth enabled RFID reader can create a low cost alternative to bulky and expensive handheld readers.
Use of RFID is a major area in which improvement in the supply chain and updating of information in real-time can boost performance without sacrificing cost effectiveness. RFID can help the oil & gas companies to sustain and compete in the cut-throat market environment. Both WiFi and UHF have been successful deployed due to these frequencies giving good performance near metals and liquids. Clearly successful deployment requires an effective data communication structure and the developments in MIMO WiFi and antenna deployment underpin this progress.
Key Application – Personnel Safety
Harsh environments such as oil and gas facilities, mines, chemical plants, pharmaceutical plants etc., require taking special measures to ensure employee safety. Conventional manual systems such as T Cards, Entry/ Exit Logs & Card Reader Systems rely on personnel to make the action of signing in & out. The availability of effective wireless networks has led to an increase in the use of personnel tracking and mustering systems. These systems provide fast, accurate data on the numbers and whereabouts of employees; absolutely vital during an emergency situation.
Increasingly these systems are being used on WiFi networks as they provide a much quicker return on investment as the underlying network can be used for a variety of other data tasks. A new generation of intrinsically safe smart phones and tablets are coming onto the market which, utilising a WiFi network will provide additional worker protection features via low cost apps, such as Lone Worker / Man-Down Protection.
In today’s highly competitive world, manufacturers and service companies in the Oil & Gas, Chemical and Pharmaceutical process industries must ensure optimum efficiency to remain competitive and achieve the expected return on investment. Now that it has become economical to access the large amounts of plant data previously trapped on “data islands” a whole new era is born. The step change to process optimisation, efficiency gain and plant data visibility is now happening using wireless networks and wireless equipment. Applications once deemed impractical and too costly are now a commercial reality.
About the author:
Ross Tye is Marketing Manager at Extronics, which he joined in 2010. He has held senior marketing positions at Kalamazoo’s Computer Division and the Co-operative Wholesale Society, as well as running his own network integration company, which was sold on to Capita.
In 2014, Extronics was awarded the Queen’s Award for Enterprise: International Trade.