ARE YOUR INTERLOCKS TESTED?

A fire broke out in a chemical warehouse that was inactive at the time. The flames had spread through the area used to store acids, bases and peroxides and included 28 storage tanks. This area is separate from the flammable products area. The site's Internal emergency Plan (IOP) was initiated. 

Six tanks containing hydrochloric acid, potash, flocculant, alkaline solutions and soda were destroyed, and the flames damaged five others. Overheating of a heating element in an empty soda tank over several hours caused the incident, as the product low-level detector had not switched off its power supply. The energy produced melted and then ignited the tank filled with HDPE (high-density polyethene). The material of which tank is made of then also fuelled the fire. The operator implemented the following preventive measures: - no heating device on product storage tanks not requiring it; - preference is given to steel or stainless steel tanks with electric or hot water heating; - the new plastic tanks are heated by hot water only; - the heating power must not allow a tank to ignite, - the reliability of the controller used to regulate the tank heating systems must be improved.

Source:Aria database

A process control system can in no way be equated with a safety system

 Inside a chemical plant, a sulphur dichloride (SCl2) leak on a pipeline supplying the boiler tube of a distillation column hydrolysed, thereby generating a strong emission of hydrogen chloride (HCl). 50 ppm of HCl were recorded inside the building. Operating losses were valued at Euros 270,000 (the downstream unit stayed idle for 18 days). A pressure sensor was undergoing maintenance; it had been diagnosed as defective after indicating a reading of 108 mbar of pressure at the boiler tube output, thus triggering closure of the valves controlling SCl2 supply and regulating the vapour heating the boiler tube. Since the sensor was not «fail safe», its electrical disconnection caused the vapour regulation valve to open, thus heating the boiler tube, whose temperature rose from 24° to 120°C in 30 min, and causing the emission of SCl2. Several measures were adopted as part of the feedback provided: monitoring and intervention procedures in a degraded operating mode, modification of the sectional valve / pressure sensor assembly, introduction of a positive safety loop independent of the regulation, thereby prohibiting any automatic restart once the high pressure threshold had been reached. This accident demonstrates that a process control system can in no way be equated with a safety system. More specifically, industrial automation satisfy a rationale and criteria that are not all known by response teams and that do not necessarily incorporate degraded modes and lockouts situations.

Source: Aria ACCIDENT ANALYSIS OF INDUSTRIAL AUTOMATION

FAULTY LEVEL INDICATIONS CAUSES FIRE

 A fire broke out on the vacuum distillation unit in a refinery during its shutdown. The unit had been restarted the day before following the acceptance of the work, while other job sites were still underway at the site. The reheating operation had begun during the night, and the unit was still in the power build-up phase. At around 9.15 am, thick black smoke was observed coming from the stack (fire in the furnace), with flames shooting from the open explosion vents. This situation was preceded by hammering in the pipes and rising pressure in the tower increase and the opening of valves: hydrocarbons began spilling outside. Following the inquiry, it appears that erroneous level indicators caused the tower to be overfilled then the backflow of liquid into the furnace via the vacuum system (backflow of incondensable materials). A brief summary of the findings: the local levels were not visible, the chain associated with the control levels in the bottom of the tower had not been completely checked (card), and the configuration of the system and notably the extraction levels were not correct.

Source: Aria ACCIDENT ANALYSIS OF INDUSTRIAL AUTOMATION

AUTOMATION INCIDENTS IN PROCESS SAFETY

 "The factory of the future will have only two employees, a man and a dog. The man will be there to feed the dog. The dog will be there to keep the man from touching the equipment.» Warren G. Bennis, North American consultant,1996"

HCL LEAKS FROM FURNACE FOR 10 MINUTES In a chemical plant, 0.6 tons of hydrogen chloride (HCl) escaped during a 10-minute period from all furnaces and vents within the potassium sulphate workshop while cleaning the HCl circuits. An employee living adjacent to the site notified the guard house of the presence of a cloud originating from the plant. The emergency sprinkling system connected to the washer was turned on to stop these emissions. Poor calibration of one of the two devices used to measure gas pressure at the furnace outlet (not directly related to the ongoing works), causing the control valve on the gas evacuation circuit to close, was responsible for this incident: since gases were no longer being drawn, they escaped from the furnaces. The lack of an alarm on this control parameter slowed personnel response, and the absence of any means for comparing the 2 pressure measurements prevented the detection of sensor drift. To reduce the probability of repeat occurrence, an alarm was installed to detect deviations between the 2 pressure readings; also, a procedure laying out the most sensitive steps, in particular those requiring a supervisor's presence, was issued.

Source: Aria ACCIDENT ANALYSIS OF INDUSTRIAL AUTOMATION

Managing the risk of the Internet of Things - Control Engineering

"Nearly two decades ago, a disgruntled former employee used network access to remotely release sewage.

In 2007, researchers demonstrated that a generator could be destroyed by remotely opening and closing circuit breakers rapidly.

In 2014, hackers broke into the industrial network of a German steel mill and prevented a blast furnace from shutting down. 

With respect to the more modern IoT devices, a researcher hacked his insulin pump, others managed to compromise smart meters, and, in a segment aired on "60 Minutes," Defense Advanced Research Projects Agency (DARPA) scientists remotely controlled automobile brakes"

Read the article

 https://www.controleng.com/articles/managing-the-risk-of-the-internet-of-things/

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Industrial Internet of Things in safety applications

Fast Forward As more wireless and Web-based applications boost IIoT adoption, some functions have moved into safety areas.The wireless diagnostic devices and applications available now covers a huge range and continues to grow.The same techniques used to monitor equipment condition can also be used to monitor safety devices and systems protecting the plant.

 https://www.isa.org/intech-home/2018/march-april/features/iiot-in-safety-applications

Employee Location Monitoring in a Post-Pandemic World

Employee Location Monitoring in a Post-Pandemic World: The COVID-19 pandemic has unearthed a number of challenges for power plant managers. However, technology exists to keep workers safe. Through the use of Location Anchors and WirelessHART infrastructure

SIL and functional safety in rotating equipment

 SIL (safety integrity level) is a very important safety indicator that has been extensively discussed, described and often misunderstood within the industry over the past years. The purpose of this article is to provide operators, reliability engineers, instrumentation engineers and department managers with a practical overview of the areas where SIL and functional safety are important in their daily business life. Note that, in the light of the International Electro-technical Commission (IEC) and most other safety relevant standards, risk is strictly defined as “harm to health safety environment” (HSE).

 Read more at SIL and functional safety in rotating equipment

Protect control valves when production slows

Protect control valves when production slows

ISA - INDUSTRIAL INTERNET OF THINGS IN SAFETY APPLICATIONS

Good article...
Industrial Internet of Things in safety applications

Cybersecurity and physical safety in the plant | Engineer Live

Cybersecurity and physical safety in the plant | Engineer Live

The internet of zombies | Engineer Live

The internet of zombies | Engineer Live

PLC and DCS: How Do They Differ & How Did They Come About?

PLC and DCS: How Do They Differ & How Did They Come About?- Automation.com

Redundant solenoid manifolds

https://www.processingmagazine.com/redundant-valve-manifolds-help-hipps-achieve-sil-3/

Cross sensitivity of detectors

During an examination of a liquefied natural gas (LNG) carrier whose cargo tanks contained ethylene vapors, CO (Carbon Monoxide) gas alarms were received which were traced to an eight-inch crack on a cargo vapor line.
It was noted that the molecular weight of Ethylene (28 g/mol) was identical to the molecular weight of CO, which accounted for the CO PPM readings.  Coast Guard personnel contacted the manufacturer who confirmed that gases such as methane, propane, ethylene and mercaptan, could actuate the CO sensor without ever coming into the range of the LEL limits.

As a result of these events the Coast Guard “strongly reminds all surveyors, marine inspectors, port state control examiners, and any other persons utilizing portable gas monitors and detectors while working onboard on Liquefied Gas Carriers to remain acutely aware that the ethylene gas vapors can exhibit cross-sensitivity.  This issue is not limited to the monitors that the Coast Guard uses but also those made by other manufacturers.  Everyone using a monitor must be aware that if the CO alarm goes off it may be an indication of dangerous gases or chemical vapors and not the presence of CO.  When the alarm sounds users must take corrective action to minimize exposure risks.”
Courtesy: USCG

New IEC 61511

https://www.chemicalprocessing.com/articles/2018/does-your-existing-sis-get-the-job-done/?show=all

Anatomy of an attack on Industrial Internet of things

https://www.darkreading.com/vulnerabilities---threats/anatomy-of-an-attack-on-the-industrial-iot-/a/d-id/1331097?

Safety and automation

https://insideautomation.net/safety-automation-evaluating-a-critical-relationship/

Alarm floods and plant incidents

Alarm floods and plant incidents

The issues in BA and back up systems

The recent problems in British Airways flights all around the World due to failure of their computer systems is being attributed to a power failure and the back up systems did not come in line. Even though you have power back up systems, have you tested the time it requires to kick in? There are lessons to be learnt from the BA incident including crisis management.....

Contribute to the surviving victims of Bhopal by buying my book "Practical Process Safety Management"