In a Hydrocarbon Engineering article, Emerson’s Amanda Alexander describes two ways to extend existing wireless networks for worker location and toxic gas monitoring.
Emerson colleagues who were around back at the dawn of WirelessHART tell me the earliest deployments were usually limited to monitoring applications. At that time there wasn’t a long enough track record of reliability for us to suggest this still-new technology for real-time control. It didn’t take long for our customers to get ahead of us and use it for control of low-criticality loops anyway because they saw the value very quickly. They weren’t disappointed.
Although wireless isn’t yet widely used for safety instrumented functions (SIFs), this doesn’t mean WirelessHART can’t be used in critical ways to make plants safer. Pursuing two of these possibilities is the topic of my article in Hydrocarbon Engineering. The article looks at personnel location awareness and toxic gas monitoring, with both systems using the same WirelessHART infrastructure as conventional process instrumentation. Let’s look at location awareness first. Most competing systems are built using Wi-Fi infrastructure, but this is very expensive.
Creating a location system using WirelessHART involves more than adding new process instruments to the network. The location triangulation functions operate with a different type of device called a location anchor. These communicate with each other and the WirelessHART gateways and access points similar to conventional WirelessHART instrument transmitters. Anchors communicate with the location tags that individual workers wear in the plant environment, and they provide the means to triangulate and determine where each tag/worker is located.
Emerson Location Awareness is supported by data processing software able to provide functions such as geofencing, mustering, and alerting of an emergency in progress. Using WirelessHART, even if it requires adding a few anchors in the plant or facility, is far less expensive than trying to achieve the same level of precision using Wi-Fi.
The second application is much more like adding conventional process instruments. WirelessHART toxic gas transmitters, such as Emerson’s Rosemount 928 Wireless Gas Monitor, can detect one of several target gases, depending on which Rosemount 628 Universal Gas Sensor module is mounted in the monitor. Its data can be displayed on a preconfigured dashboard to help operators in the plant and control room know there is a gas release in progress. Location awareness can show which workers might be in harm’s way and if they need to be moved to a safer area, and worker location can then be tracked using Location Awareness.
Extending the WirelessHART networks that you already have is an effective and economical way to extend protection for your people. Begin by thinking about where you are now. Do you know where your workers are in the plant, or do you still depend on walkie-talkies? Ditto for toxic gas emissions. Are peoples’ noses still the primary detection method?
Visit the Control & Safety System and Flame and Gas Detection pages at Emerson.com for more on technologies and solutions for safety strategies. You can also connect and interact with other engineers in the Oil & Gas and Chemical Groups at the Emerson Exchange 365 community.
