the story So Far: One Explosion at Barzan gas facility in Ras LaffanOn June 21, Qatar took the lives of 12 Indian workers and one Pakistani worker. While local authorities have just begun their investigation, QatarEnergy, the country’s national energy company, which maintains the gas facility, said the explosion occurred as workers were restarting it — pointing to a well-known risk but poorly managed type of industrial activity in India, called a transient process.
How can starting again be dangerous?
An industrial plant is often at its most dangerous, not when it is running at full capacity as it was designed for. It is more dangerous when it is starting up or shutting down because during these transient operations, the facility is going from one state to another.
In fact, a typical industrial facility will spend more than 90% of its time in steady-state operation, that is, when it is not switching between states. During this period, variables such as temperature, pressure, and flow rate are fixed and/or predictable. On the other hand, data evaluated by organizations such as the Center for Chemical Process Safety consistently show that approximately 50% of all process safety incidents occur during the remaining 10% of the time when the facility is in transient mode.
Recent examples of such accidents in India include the Ascientia Advanced Sciences explosion in Andhra Pradesh in 2024, the Amudan Chemicals explosion in Maharashtra in 2024, and the Vedanta Power Plant explosion in Chhattisgarh in April this year.
Why are transient procedures so risky?
In technical terms, during transient operations, engineers say that a plant’s safety envelope is being tested in real time.
During a startup, such as at the Ras Laffan port in Qatar, the facility’s equipment is subject to rapid changes in temperature and pressure. This introduces thermal stress: different parts of the metal structure expand at different rates. So if a pipe is heated too quickly, physical expansion can cause mechanical
Failure or creep, leading to breach of containment.
In chemical reactors such as Amudan Chemicals, the concentrations of the reactants are not at their equilibrium during the initial charge. This can lead to exothermic runaway, a condition where a chemical reaction releases heat faster than the cooling system can handle it, causing the temperature to rise rapidly, posing a risk of explosion.
As was the case with the Vedanta pipeline burst in Chhattisgarh in April, equipment that was lying idle or not being properly maintained came under sudden pressure. In this part of the restart phase, hidden issues such as dead-legs, i.e. sections of pipe that do not have flow, causing moisture and rust to accumulate, or oxygen ingress, i.e. air leaking into a system that should be idle, become threats.
If a system is not properly purged using an inert gas such as nitrogen to displace oxygen and/or volatile vapors, generating sparks or heat during startup may result in a vapor cloud explosion.
Which Indian laws/rules apply to such accidents?
The Factory Act 1948 applies to almost all accidents as it addresses the duties of the operator to prevent fires and explosions, mandate safety measures and disclosures, and make emergency plans when dealing with hazardous processes.
The 1989 Manufacture, Storage and Import of Hazardous Chemicals regulations under the Environmental Protection Act 1986 aim to prevent vapor cloud explosions and other chemical accidents by requiring safety reports, on-site emergency plans, risk assessments, notification of major accidents and control of ignition sources, leaks, runaway reactions, etc.
If any source of ignition or electrical equipment contacts any flammable gas or mixture of gases the 2010 Central Electricity Authority Regulations may apply.
Under the 1989 regulations, the ‘Major accident hazard’ section calls for periodic hazard reviews, emergency drills and documented standard operating procedures for ‘abnormal’ conditions of operation, including transient procedures.
The Boiler Act 1923 and various state boiler regulations address periodic inspections, including inspection and certification of boilers and pressure systems, safe operating conditions, qualification of operators, and periods after repair or shutdown.
Finally, environmental and labor laws respectively are applied when hazardous emissions occur and working conditions, contractors’ responsibilities, maintenance and shutdown safety operations, and worker training and access to safety equipment are relevant.
What is process-safety engineering?
Preventing disasters during transient operations requires great care, but operators and workers also need to apply specific engineering concepts designed to catch errors before they result in a fire or explosion.
The first is a pre-startup security review. This takes the form of a multidisciplinary formal inspection by experts before a highly hazardous chemical is introduced into a process. Specifically, the review ensures that the hardware is built to design specifications, the software (control logic) is tested, and the ‘peopleware’ (i.e. operators) are trained on specific startup procedures.
Second, ‘management of change’ is a protocol that engineers use to evaluate the impact of any modification – whether due to changes in raw materials, equipment or personnel – before it is implemented. The power plant accident in Chhattisgarh occurred after the plant got a new owner (Vedanta) and was later restarted. An effective ‘management of change’ may require full structural integrity audits of old pipelines to ensure they can handle the forces of restart after a period of inactivity.
What are HAZOP and LOPA?
HAZOP is the acronym for ‘Hazard and Operability Study’ – a systematic method of identifying deviations from the design intent of a facility. HAZOPs typically focus on steady-state operations and are interested in questions such as how a pipe will behave if there is no flow inside it. For transient operations, engineers use procedural HAZOPs, where they analyze every single step of the startup manual.
For example, during startup of the Ras Laffan gas facility, engineers conducting a procedural HAZOP might ask, “What if a technical failure occurs exactly when gas is introduced into a component?” Then, based on the possible modes of failure, they may have installed automatic kill-switches that will immediately isolate the component.
Layer-of-protection analysis, or LOPA, is similarly a semi-quantitative tool that operators use to check whether there are enough independent protection layers to prevent an accident. One layer could be the operator, the second could be the alarm, the third could be the relief valve, the fourth could be the blast wall, and so on.
LOPA is useful in high-risk transient operations because operator vigilance alone is not strong enough to prevent a small error from growing rapidly, and often involves passive or automatic response systems.
What role does human error play?
During steady-state operations, well-equipped industrial facilities have advanced digital automatic controllers, called distributed control systems, that handle changes in parameters as necessary to prevent damage to the facility. But during transient operations, operators may convert many automated loops into manual ones – which can place a heavy cognitive load on operators. This has been called the ‘out-of-the-loop performance problem’.
This occurs when “operators of automated systems become impaired in their ability to handle manual operations in the event of an automation failure”, according to a 1995 research article in the journal. human factors. “This accounts for the potential loss of skill and situation awareness resulting from problems of alertness and complacency, the shift from active to passive information processing, and the change in feedback provided to the operator.”
For example, in the Ascientia incident in 2024, the start of a new campaign involved manual solvent transfer. When humans need to make rapid decisions amidst an alarm flood, a situation where a control room receives hundreds of alarms simultaneously, the potential for human factors error can also increase significantly.
Over time many industrial accidents in India and abroad have been traced to shortcuts that operators took during one or more of these processes. According to a comprehensive review published in Security Research Journal In 2023, when a facility has operated normally for some time and accidents become rare, the costs of safety become visible while the benefits of safety become harder to achieve. If at the same time the facility is under pressure to increase production, operators may be motivated to take greater risks – until a major accident reminds them why these safety measures were in place in the first place.
