June 26, 2011

Emergency scrubbing systems

It is very important to design your emergency scrubbing systems properly. If not, they will fail you when you need them the most. Croll Reynolds has a case history of "a relatively uncomplicated but effective method for handling large runaway emissions of TDI and solvent vapours. "
Read it in this link.

June 23, 2011

OSHA proposes fines

A news article mentions the following : OSHA has proposed fining a company $119,000/=  for 17 serious safety violations. These include "allowing cylinders to be exposed to physical damage; having inaccurate field verifications on tanks and values; using equipment that was not in compliance with recognized and generally accepted good engineering practices; failing to have clear written operating instructions for processes such as unloading hydrogen fluoride into storage tanks and switching storage tanks; failing to address human factors in relation to remote operating valves on the hydrogen fluoride storage tanks; failing to document and resolve issues addressed by the process hazard analysis team; failing to establish written procedures to maintain the integrity of process equipment; failing to implement written emergency operating procedures for emptying hydrogen fluoride tanks; failing to perform appropriate checks and inspections to ensure equipment was properly installed; and failing to establish and implement written procedures to manage changes to process chemicals, equipment and procedures. The company also was cited for a deficient incident report that did not include factors contributing to the vapor release and the recommendation resulting from the internal investigation. "
Read the article in this link.

June 21, 2011

Reactor Blast kills two

A reactor blast at a unit in Ankleshwar has killed two persons. Times Of India reports that "R S Ninama, additional district magistrate of Bharuch, said, "Preliminary investigations have found that the blast was caused by overheating of the reactor. The industrial safety department will investigate the accident and find out if safety has been compromised".
While I am not speculating on the cause of the incident, ensure that you are aware of the following:
Reactive chemical incidents are on the increase. Reasons are attributed to:
1. Lack of knowledge on process chemistry
2. Lack of knowledge on designing relief and vent systems
More and more companies are relying on in house R & D to develop new products. Unless you have a good system of ensuring that process safety is taken care of during the scale up from R & D to pilot plant and manufacturing plant, a disaster is waiting to happen.

Read the article about the incident in this link.

Electric heaters + Flammable material = Fire!

A court in UK has imposed a fine of 1.24 million pounds for an explosion in a tank in a gas terminal. A press release from HSE UK mentions the following:

"Investigators traced the cause of the explosion to a leak of highly flammable hydrocarbon liquid into a part of the plant responsible for treating waste water before discharging it into the sea.The leak was caused by the failure of a corroded metal separator vessel, which allowed water contaminated with the highly flammable condensate to enter a concrete storage tank where it was heated by an electric heater. The heater's elements were exposed within the tank, raising the surface temperature significantly causing the explosion and fire"
Read the press release in this link

June 20, 2011

Global warming and process safety

Just like the scare caused by the Y2K bug, today, chemical industries need to factor in the changes in weather due to global warming. The CSB narrated an incident where there was a propane release due to water freezing in a piping dead leg due to unusually cold weather. When the ice formed, the pipe expanded, cracked and later, when ambient temperature increased, propane came out of the crack and caused a major fire.
A news article reports another incident where a chlorine release occurred due to the freezing of a regulator due to cold weather. Though in India, we do not face such low temperatures, chemical operators must make themselves familiar with the pour points of liquids. Maybe in the not so distant future, we will be having snow and ice in India too!
Read the incident in this link

June 18, 2011

P2S5 accident

Dr Michael Fox has narrated an incident where a worker apparently inhaled P2S5 dust. he mentions that "When P2S5 enters the lungs it reacts with the moisture in the lungs and forms H2S. Only a very small particle of P2S5 is needed to produce a toxic concentration of H2S once inside the lungs. "
Read the incident in this link.
There are other incidents also which can be viewed from the above link.

Hypochlorite + urea explosion

For my friends in the fertilizer industry, Dr Michael Fox has narrated an interesting incident where an explosion killed one person. The explosion occurred when 12.5% sodium hypochlorite was being unloaded into a tank that previously contained a liquid fertilizer consisting of 78% urea and sulfuric acid (1:1 ratio). His investigation found out that when "liquid fertilizer was added to an excess of sodium hypochlorite, an extremely vigorous reaction plus significant heat was generated. One possible explanation seemed that when there is excess of alkaline sodium hypochlorite, the sulfuric acid is neutralized and what remains is sodium hypochlorite and urea, a mixture said to produce explosive nitrogen trichloride "
Read about the incident in this link.

June 17, 2011

Explosion proof and intrinsically safe fork lifts

The Hunstman Corporation has reported that it has recently completed an upgrade of their forklifts used in their Chinese facility to meet Chinese standards. The article mentions the following:
"The firm originally imported all of its explosion proof equipment from Europe to comply with EU standard (EN1755:200), American standard (UL NEC500/505) and International standard (IEC). However China only accepts its own in-house standard when accrediting explosion proof equipment.
As a result of this all equipment had to go through system upgrade to ensure that it was up to the Chinese “General Principles for Explosion Proof Industrial Trucks in Explosive Atmospheres” (GB19854-2005). A representative for Huntsman and the factory said:
“The aim was to conduct an overall system upgrade on the European converted explosion proof trucks to meet the Chinese national standard.”
The importance of using explosion and intrinsically safe equipment in potentially unsafe environments is vital, especially when transporting raw materials as is the case in the Guangzhou plant. On vehicles such as forklift trucks components such as the ignition must be adapted to prevent any spark or heat that could cause safety concerns when in the working environment.
The representative added: All the requirements of explosion protection safety management and safety supervision were considered, including, for example, the design and installation of Exd batteries and Exd lights, rewiring of Exd enclosures and changing the start-up battery on the diesel trucks.”
 Read the article in this link

Incidents with relevance to process safety also

Two recent incidents have a relevance to process safety also. In the first, a patient reportedly went into a coma after she was administered NO2 instead of oxygen. The doctors involved in the incident have reportedly been suspended but their contention is that nitrous oxide was filled by mistake in the oxygen cylinder. Ensure your gas cylinders are properly colour coded and you buy it from authorized dealers. Many plant accidents have happened when a wrong gas cylinder was connected and caused an inadvertent reaction.

The second incident, sent by Mr P.Vijayaraghavan, mentions that a housewife was killed due to burns when she sprayed insect repellant near a gas stove that was burning. Insect repellants are propelled by flammable gases. So are some hair sprays. Pressurised spray cans are also used in industry for dye checking etc. Ensure that people read the warning signs written on the cans before they use the can.
Please spread this message. It may save a life.

June 15, 2011

Process Safety Violations and fines

OSHA has cited a chemical plant for 18 violations, 16 of them considered serious and one labeled "willful."
The news article mentions the following:
"A willful violation is one committed with knowledge of and disregard for the law, or with indifference to worker safety.
OSHA's serious violations included failure to provide a proper hydrogen gas detection system, over-pressure protection, emergency egress, personal protective equipment and hazard communication training. It also cited AL Solutions for failing to safely store flammable materials and ensure the safe use of forklifts.
A minor violation was for failing to keep proper injury and illness records.
OSHA said AL Solutions is now in its Severe Violators Enforcement Program, designed to focus on "recalcitrant employers that endanger workers by committing willful, repeat or failure-to-abate violations."
Read the article in this link.

June 11, 2011

Submersible pumps and safe work practices

A friend was mentioning about an incident in his plant where a submersible pump was removed for maintenance. The tank contained a molten chemical. The opening where the submersible pump was fixed, was covered with a thin plywood cover. A trainee who was interested to know what was going on, accidentally stepped on the plywood cover which did not hold his weight. The cover gave way and opening was just sufficient for him to slip inside upto his armpits. Luckily other operators were around and lifted him up.
Do your job hazard analysis properly when you issue a permit. It is always better to custom make proper metal covers which are bolted down in place when submersible pumps are removed.

Cooling water treatment without chemicals

I came across an article in which mentions the elimination of chemicals and their associated handling hazards in the treatment of cooling water. The article mentions the following:
"To resolve many of the issues associated with chemical treatment, technologies using non-chemical treatment have been evolving. Non-chemical devices (NCDs) use many different technologies to achieve biological and corrosion control. Over 30 suppliers are known to provide commercially available products that can be grouped into four basic classes or methodologies: magnetic devices; induced electric field devices; ultrasonic devices, and mechanical energy devices.
How CHC Works
The CHC unit consists of a pressure equalizing chamber and a cavitation chamber. Inside the cavitation chamber, two pairs of nozzles are positioned opposite each other at specific distances, lengths, and angles. Water is first pumped into the pressure equalizing chamber at a pump pressure of ~70 PSI. From the equalizing chamber, water is channeled into the cavitation chamber, where water is forced to rotate with high velocities. The rotation of water streams creates a high vacuum, typically greater than -30 inch Hg. This high vacuum condition causes micro-sized bubbles to form in the water streams. These bubbles are filled with a mixture of vapor and dissolved gases. The water streams in two nozzles rotate in opposite directions. Meanwhile, the water streams travel forward at accelerating speeds. Upon exiting from the nozzle, the opposite water streams collide at the mid-point of the cavitation chamber. At this point, pressure increases spontaneously, causing the sudden implosion of micro-sized bubbles. At the moment of collapse, hydrodynamic cavitation generates intensive shocking waves and produces extremely high temperatures. Under these conditions, chemical reactions such as conversion of dissolved calcium and bicarbonate ions into calcium carbonate (CaCO3) and oxidation of organic compounds can occur. In addition, the bacteria in the water are ruptured by mechanical, physical and chemical forces".

Read the article and see the images in this link.

June 9, 2011

Fire in refinery furnace injures operator

A fire in a furnace in a crude unit in a refinery in the USA has critically injured a worker. He apparently inhaled superheated air. I can imagine the terrible internal burns he must have received. The cause is being investigated.Read about the accident in this link.
OSHA has a good technical description of refinery processes and their safety hazards. Read it in this link.

June 8, 2011

Learning lessons

The investigation of the refinery tank explosion that killed 4 persons is underway. A BBC news item mentions the following:
"Maintenance work had been carried out on a 730 cubic metre storage tank which exploded on Thursday evening, damaging an adjacent vessel.Dr Ivan Vince, a safety, health and environmental specialist at ASK Consultants told BBC Radio Wales that the investigators will look at two types of causes.
"The first part of the investigation is narrowing it down to exactly what happened and what were the immediate causes," he said. It could be some time before the cause of the explosion is known."Then the route cause investigation looks at the bigger picture like the safety management systems, the adequacy of the training and procedures in general or deeper, the status of the safety culture, the working environment in general."I have never come across a situation where there have not been lessons to be learnt. The problem is lessons are learnt but then forgotten when personnel change."
The last statement is highly significant. Organisations should implement and sustain a process safety knowledge management system.Otherwise, as people change, their knowledge goes with them.
Read the article in this link

June 5, 2011

A piece of cloth causes chlorine release!

An interesting incident is mentioned by Stephen P. Andrew, T. Kim Parnell, Robert Caligiuri, Lawrence Eiselstein of Parnell Engineering and consulting:
"A process upset at a chlorine production facility resulted in a release that forced the partial evacuation of a nearby town. Investigations revealed that the events commenced with the failure of a shell and tube heat exchanger used to condense chlorine gas. Post-incident inspections revealed a cloth at the liquefier coolant inlet that accelerated the flow in that region, causing certain tubes to be breached. As a result, the water-based brine liquefier coolant was entrained in the chlorine process stream, forming a highly acidic oxidizing mixture. This corrosive mixture then flowed to the chlorine storage tanks destroying an elbow in the tank inlet piping and rendering the tank shut-off tank valve ineffective, thus allowing chlorine to vent into the atmosphere".
Read the detailed report in this link. 

June 3, 2011

Tank explosion in refinery

An incident in a refinery in the UK has reportedly killed 4 persons. The Telegraph reports the following:
"Four people were killed yesterday evening when a 730 cubic metre storage tank exploded in what appears to have been a tragic industrial accident.This is the first serious accident at the plant. Previous incidents include a small fire caused by a hydrogen leak in 2001 and two fires in 2003 in which no one was seriously injured.John Davies, leader of Pembrokeshire Council, praised the refinery's safety record saying: “I have known it all my life and this is first time as far as I am aware that a life has been lost in similar circumstances. It has an exceptional (safety) record.”
The refinery is one of the largest in western Europe, employing 1,400 people".
Read the article and see the video of the tank and spokespersons comments in this link  We have to wait for the investigation to see why this happened.
See some photos of the explosion in this link.

Understand the basics of chemical safety while managing change

The International Program on chemical safety has a good basic write up on chemical safety - corrosive materials, incompatibilities, materials of constructions, storage and effects of chemicals on concrete. Many times, we tend to forget the basics when managing change, that later results in an incident.
Read the article in this link.

June 1, 2011

Welder killed in accident

A regulator of a gas cylinder apparently malfunctioned and came out, killing a welder on the spot at an accident in a factory in Odisha. Times of India reports the following:
 "In the accident, Rawat`s leg flew 50 m away from the spot, while the palm of his left hand is still missing, Ponda sub-divisional fire officer Parab said. Quoting the factory officials, Parab said that the blast was the result of a broken knob of a gas cylinder with which Rawat was cutting metal sheets at the Kundaim-based iron plant. "As the cylinder's knob was broken, the force of the gas centered around the knob and moved out with a tremendous force that caused the blast," Parab said."
Treat your gas cylinders and their fittings with respect. I keep observing scant disregard for the handling and safe usage of gas cylinders at many sites. Read the article in this link.

Process safety and metrics - don't get lulled into a false sense of security!

There has been a lot of discussion on how to make process safety management work and new initiatives like risk based PSM and others have been suggested. These include metrics for tracking of process safety performance. The old adage " what cannot be measured cannot be managed" is true for process safety, too. However, I observe a stark difference between metrics for measuring PSM performance and UNDERSTANDING that measurement. In many of today's chemical companies, the board of directors often do not have a person competent to analyze the PSM metric that is being displayed. With the net result that the number being displayed is just that - a number. For example, if a metric that is being displayed to the board is the pending items from a process safety audit, the actual number may be less but its severity may be very high. What is the solution? There is only one answer - the board of directors of chemical manufacturing companies should ensure that there is someone competent to analyse the PSM metrics for them.