What Smart Plants do for Greater Situational Awareness

28 April is the World Day for Safety and Health at Work #SHWDay setup by the International Labour Organization (ILO) which is a specialized agency of the United Nations. Safety and health in the plant is important so this time I’ll shine the light on some recent developments in automatic monitoring which can improve safety and health in smart plants. Can the digital ecosystem solve problems to help the industry further improve personnel safety and health in the plant? Here are my personal thoughts:

The industry has done a fantastic job of reducing accidents, emissions, and injury etc. Yet incidents still occur every day. See for instance US Chemical Safety Board chemical accidents in the news reel. Industrial incidents recently reported include leaks, fires, explosions, spills, injuries, burns, blasts, contamination, blaze, evacuation, persons killed or hurt, and long incident response time.

Also, new HS&E regulations with new requirements are coming into effect on a regular basis with requirements for incident response time, effluent and emissions monitoring and reporting, as well as inspection and verification. A second layer of automation can help meet these new requirements.

Improved Health

Innovative use of automation has created a number of solutions which can have a positive effect on personnel health

Emergency safety shower and eyewash stations

Plants have emergency safety shower and eyewash stations for personnel to rinse off hazardous chemicals they have come in contact with. While doing so they may not be able to call for help on the walkie-talkie at the same time, or may not be able to give their location accurately. There have also been cases where the radio set was rendered non-workable by the water. While most modern plants have the safety shower and eyewash stations connected to the control system, many old plants do not. Old plants can be modernized by adding wireless discrete input transmitters for monitoring of the safety showers, notifying operators if a safety shower is activated, and exactly where, such that first aid responders can be dispatched quickly to assist the person in distress. A fast response is important to minimizing the extent of the injuries. In cold climates, pressure and temperature sensors can also be added to monitor the water temperature to detect too cold water or freezing. The monitoring also helps with regulatory compliance for incident reporting and as automatic recording of safety shower testing as proof of safety compliance audits. Countries like USA and regions like Europe have regulations for safety showers, such as OSHA 1910.151B requiring response within 4 minutes or less, as well as ANSI Z358.1.2009 and EN 15154 requiring weekly inspections and annual functional tests. Other countries may not have such regulations right now, but may institute such regulations soon. Some companies also have such regulations. Other companies may follow.

Manual data collection

I have written before about how automating manual data collection with sensors is easy with wireless or fieldbus and results in more accurate and timely data for a more predictive operation than mechanical gauges and portable testers. There is also a personnel safety aspect to automating data collection in that people spend less time in the field which means reduced risk of possible burns from high temperature of piping, vessels, and equipment, as well as avoiding the need to climb over or under pipes and vessels which could be unsafe. Not to mention avoiding slips, trips, and falls, especially during inclement weather and at height. Reducing the burden could possibly also relief some stress.

Greater Safety

Clever use of sensors has also produced a number of solutions which make a smart plant a safer place to work

Manual valve position

Plants have hundreds or even thousands of manual valves. When we read about accidents we often learn that the investigation found that the root cause was a valve which was supposed to be closed had been left open. This may include for instance isolation valves, dyke drainage valves, or sampling valves, and in some plants even ESD bypass valves. The information may not have been passed from one shift to another. Such accidents could perhaps have been avoided if the operators had the valve position indicated on the console screen which is easily accomplished with wireless position transmitters.

Product transfer valves in tank farms if not lined up correctly may result in product being pumped into the wrong tank resulting in overfill, spill, and possibly fire or explosion. Valve position feedback can possibly avoid such incidents or product mixing by incorporating interlocks in the control system.

Shutdown valve position and performance

Plants have several Emergency ShutDown (ESD) valves for which operators would like to see confirmation of successful actuation and which must perform within expected response time. While most modern plants have monitoring devices on their ESD valves, many old plants do not, and therefore instead require time consuming manual stroke time testing which can be particularly challenging in remote locations such as on unmanned offshore platforms. Old sites can be modernized by adding wireless position sensors for monitoring of the valve position and verifying the stroke time providing operators reassurance the valve is in a safe state and identifying need for overhaul. Note that wireless is not part of the safety function.

Storage tank breather valve and blanketing

A failed breather valve on a storage tank may cause the tank to explode or implode during filling, emptying, or temperature change. A discrete transmitter can monitor breather valve operation and detect if it fails thus avoiding potential tank rupture and possibility of spill, fire, and explosion. Similarly, transmitters can monitor that the tank blanketing valve is functioning correctly.

Coal pile fire

Coal fired power plants have piles of coal. Other plants may have stacks of similar combustible materials. There is a fire hazard should the temperature in the pile get too high. Monitoring the temperature in these stacks is a challenge because these piles “move” as the coal is consumed from one pile and as deliveries are taken in new stacks. Since these piles do not stay in one place, plants now use wireless temperature transmitters on “spears” which are moved from stack to stack to detect and alert operators to rise in temperature before a fire breaks out.

More Environmentally Friendly

Smart plants are made more environmentally friendly by novel ways of deploying sensors.

Relief valve release

Pressure relief valve (PRV), pressure safety valve, pressure relief device, or pressure safety device – call them what you like but they are important for process safety. However, when they release to flare or the vent system they impact the environment as does seat passing and simmering. Product losses also result. Wireless position and acoustic transmitters are able to detect lifting and simmering to automate reporting. Moreover, by historizing these events and correlating them to process data, plants may be able to make adjustments to the process or equipment to reduce flaring and venting in the future. Acoustic transmitters are also able to detect seat passing which can be used to schedule valve overhaul to stop losses. Pressure transmitters can detect rupture disk pinhole leak. Countries like USA have regulations that apply to this, such as the Clean Air Act.

Hydrocarbon leak/spill

Hydrocarbon leaks and spills may result from faulty pump seals, valve stem packings, tank overfill, or tank damage such as a corroded tank bottom. By deploying hydrocarbon liquid detection sensors under or around tanks, in pump sumps, pits, and storm water drains etc. liquid hydrocarbon leaks can be detected sooner. This results in reduced emissions and reduced fire hazard.

Cooling water discharge

Many plants use cooling water from the sea, a lake, or a river. If the discharge water temperature is too high, the marine life may be affected. Therefore many countries have regulations on cooling water discharge temperature. If the plant doesn’t already have this temperature measurement, adding a fieldbus or wireless transmitter is very easy.

Shared Infrastructure

These are just some of the many health, safety, and environment solutions I have seen. The beauty is that there is no need to install dedicated network infrastructure for these HS&E solutions. Many plants already have a plant-wide WirelessHART network where the sensors can easily integrate. That is, the same wireless network used for reliability, maintainability, energy efficiency, integrity, and productivity is also used for HS&E. For plants built on Foundation Fieldbus, many of these sensors can alternatively use fieldbus transmitters connected to existing fieldbus networks in the nearest field junction box.

Speak to the HS&E officer in your plant about a plan to deploy these solutions. If the plant does not already have a wireless sensor network, talk to the I&C department about deploying wireless infrastructure. Arrange for a plant modernization audit to identify the missing measurements. Well, that’s my personal opinion. If you are interested in how the digital ecosystem is transforming process automation click “Follow” by my photo. Click “Like” if you found this useful to you and share it with others if you think it would be useful to them.