November 10, 2018

Minimizing Fire and Explosion Hazards in dusty systems

Minimizing Fire and Explosion Hazards in Dusty Systems: Having honest conversations about material handling hazards allow risks to be properly addressed, thereby reducing fire and explosion threats.

November 2, 2018

12 Tips for Centrifugal Pump Safety

12 Tips for Centrifugal Pump Safety: Centrifugal pumps are used in industrial settings, and there are several steps that should be followed to ensure safe and efficient pump operation.

October 29, 2018

On April 6, 1994, a unit operator was conducting rounds of the coker unit when he observed a leak coming from the mechanical seal of the heavy gas oil pump of coker unit #1. The operator decided to seek assistance; the head unit operator and six or seven unit operators responded. The operators placed water and steam on the leak to suppress the vapor from the seal. The head unit operator decided to shut down the pump and transfer the product to the secondary pump. As the operator shut down the primary pump, the mechanical seal blew, causing a vapor cloud to generate from the seal. The operators continued to put steam and water on the seal and isolated the pump from the pipe line. The remaining product in the pipe line leading to the primary heavy gas oil pump vaporized, leading to the dispersion of the vapor cloud. The operators who responded were wearing bunker gear and several wore emergency respirators. Those with respirators isolated the pump from the pipe line by closing the suction and discharge valves. The operators who were not wearing emergency respirators stationed themselves upwind of the vapor cloud and put water on the cloud; however, the wind changed direction several times, exposing unprotected operators to vapors. Employees #1 and #2, two unprotected operators who responded to incident, were brought to Hospital to be treated for inhalation of hydrocarbons. Employee #1 was hospitalized.
Source: OSHA

October 24, 2018

Hexane Vapors Ignited By Static Electricity; Worker Burned

Employee #1 was standing at the exit end of a conveyor, peeling off a build up of hexane adhesive from the inside of a stainless steel dip tank. A static discharge of electricity, apparently generated by the peeling action, caused a flash fire. Employee #1 suffered second degree burns on the back of his hands and his upper chest and neck. The tank is 12 inches by 15 inches by 22 inches in size. The employee was pulling adhesive from the back side of the tank when the fire started. All the equipment in the area is grounded and bonded and approved for the location. The flash point for hexane is -23 degrees.
Source:OSHA

September 18, 2018

Leak due to vibration

A specialized rubber manufacturing plant experienced leakage of a hexane solution from a pump discharge flange during use. The hexane vapor was ignited by a st atic electricity spark and a fire occurred. Apparently, the flange was loosened by vibrations from the pump.Routine operations were being carried out on site at the time of the accident.
The operation involved the transfer of a hexane solution from an un-reacted raw material recovery tank to the washing process through the outlet of the first flange of the pump. The hexane solution
leaked, ignited, and burned. The financial costs of recovery and lost production were significant.
Causes
The cause of the accident was a loose flange that resulted in leakage of a flammable substance. During the operation, a previously undetected cavitation in the pump produced significant vibration
which loosened the flange. As a cause of the ignition it was considered that the hexane was charged when it spouted from the flange, and static electricity was discharged; then hexane vapor ignited
and a fire occurred.
It was considered that the vibration might have been intensified by the passage of an insoluble polymer lump through the pump, a malformation in the substance generated on the piping wall. In addition, a reducer connected a 3-inch (~75mm) flange of the discharge pump to 6-inch (~150mm) piping. The looseness of this flange might have been accelerated when the force
of vibration was added on the piping.
Lessons learned
Vibrating equipment can increase potential for stress fractures and gaps from loosely fitting interfaces, all of which can be sources of leaks that, if undetected, may result in an accident. It is necessary to pay sufficient attention to vibrating equipment, especially pumps that may be found in many processes throughout the site. Control measures to mitigate potential risks could include regularly scheduled inspections in line with existing technical standards or in-house experience, particular attention to small-bore piping (vulnerable to fatigue), installation of a  vibration monitor to detect and locate abnormal vibration patterns, as well as other measures available in guidance
on vibrations from numerous sources.
Source: European Commission

September 14, 2018

Common Causes of Gasket Failure

Common Causes of Gasket Failure: During the course of our 50 years in business, Associated Gaskets has seen many different types of gasket failures. Sometimes these were seen late at night when we were called out to help with an emergency, other times it was when one of our own gaskets was returned after failing …

September 6, 2018

Global warming and its effect on process incidents

As the effects of global warming are being felt, chemical industries must acknowledge the fact for planning for natural disasters. The "Fire from ice" video about the Valero refinery incident and The Arkema incident due to Hurricane Harvey are two examples related to climate. Cyclone maximum wind speeds are increasing and past weather data may not be a reliable predictor about the future. What are you doing about it?

September 3, 2018

Gasket failure incident

On 5th January 2008 a production operator discovered a fair sized phenol leak in the phenol pump house next to the phenol storage tank. One of the gaskets on the flange connection on the outlet pipe of the tank had failed. The head of the operations department tried to stop the leak by tying a rubber belt around the flange. In the meantime, an operator sprayed water on the flange to avoid contact with phenol as much as possible. The phenol that had leaked was collected in a catchment pit of 20 m3 underneath the pump house. This catchment pit had a high level alarm, but it was not functioning at the time of the leak. The company was not aware of the malfunction because the alarm was not subject to periodic inspection.
An attempt was made to close the only manual valve on the pipe,located between the inner and the outer tank shells, but the valve spindle broke off during this manipulation, so the line could not be
shut off. After the temporary repair of the flange connection, three leaks continued to release phenol, which were also collected in the catchment tank. It was not allowed for the employees to enter the
pump house while the phenol was leaking. To clean up the catchment pit, the company provided a waste tank big enough to contain all the leaked phenol. When starting to pump the phenol from the catchment tank to the waste tank, it was discovered that the catchment pit had overflowed. Part of the
phenol/water mixture had passed over the rim of the open pit into the municipal sewer system. At the time, it was not yet known how much phenol had leaked to the sewer system.
On 7th January 2008 it was decided to start up the phenol-based batch production to consume all phenol in the storage tank since the phenol tank had to be taken out of service in order to replace
the gasket on the flange. On January 8th, after a few batch productions, it was found out that the level indicator in the phenol storage tank had become stuck since the last control of the level on 4th January (comparison of manual level measurement with level indicator). Only at that moment did the company realize that 25t of phenol had leaked out of the tank. The catchment pit probably
collected most of the release, but more than 5t of the phenol spilled into the municipal sewer. No consequences were reported as a result of the release into the municipal sewer. A specialized
company was hired to repair the remaining phenol leak.
Causes
In this case, a variety of causes contributed to the accident. The direct cause was the degradation of gasket that caused the leak. After the flanges and valves were replaced following the accident, it
was discovered that the valve broke down because the gasket next to it had been reacting with phenol over the course of many years, leading to a solid deformation that prevented the valve from moving,
hence, the valve could not be closed. The spindle of the manual valve at the tank broke off as a result of the deformation of the adjacent gaskets.
Source: European commission

August 27, 2018

Rupture of sulphuric acid tank


On 4th February 2005 a storage tank containing 16,300 t of 96 % sulphuric acid ruptured. The entire contents of the tank were spilled out into the bund and then overflowed out into the nearby dock. The environmental consequences of the accident were quite significant,the sulphuric acid emission had a serious effect on local flora in the inner and deepest parts of the harbor and harbor entrance area. When the sulphuric acid came into contact with the salt water an exothermic reaction occurred, producing a vapour cloud consisting of hydrogen chloride that drifted northwards along the coastline in the direction of the wind. Fortunately, the wind was blowing towards the sea and away from populated land areas and the cloud diluted very quickly. After the spill approximately 2,000 t of contaminated sulphuric acid remained in the bund. The acid also soaked into about 100,000 square metres of the ground surrounding the spill.
Causes
The cause of this incident was a leak in an underground coolant supply pipe of reinforced concrete installed over forty years before that resulted in a weakening of the ground under the tank farm. Apparently, water forced its way out of the pipe, eroding the ground near and around the sulphuric acid tank. This erosion damaged the ground under the tank which ultimately failed due to the lack of support of the tank floor. A study of the appearance of the involved part of the coolant supply pipe suggests that the corrosion was a result of an acidic attack on the concrete.
Important findings
• The damage indicates that the acid exposure occurred over a long period of time. However, it was not possible to determine the exact duration of the exposure.
• The pipe had been in use over many years and the operator had mno suspicion that the pipe was suffering severe degradation. The inspection of the failed pipe after the incident detected little or no internal corrosion, but heavy external corrosion to the concrete. In certain places the concrete had corroded so severely that the reinforcing steel was exposed.
• According to the German standard, DIN 4030 (equivalent to the European standard, EN 260) a strong attack on concrete occurs if the pH level in surrounding water is < 5.5 and a very strong attack can occur if the pH level is < 4.5. Fifteen years before the accident a ground pollution study was carried out in the area, during which one of the sample taking points was close to the failed coolant supply pipe. At this point the pH level was measured at 4 in the shallow groundwater. With this knowledge the company drew the conclusion that this pH level entailed risks for strong acidic attackson the concrete.
Lessons learned
• The uneven corrosion on the outside of the pipe can possibly be explained by the fact that it lay partly in groundwater flow. In this environment, the acid can pass through the barrier more easily, and the reaction products (gypsum) formed can be more easily dissolved. As such, the concrete barrier was not as effective as on the part of the pipe that remained in drier surroundings. Therefore, concrete piping exposed to ground water should be should be subject to protective measures, monitoring and inspection to take into consideration the increased risk from groundwater exposure.
• Similarly, underground piping that entail risks to foundations should be inspected and measured..
• There are a number of strategies that can be applied to piping where there is accelerated potential for degradation or where there are high consequences should significant degradation occur.
Pipes may, for example, be tested for stability (remains in place) and hydraulically checked on a regular basis. Alternatively, consideration should be given to positioning the pipe above ground. The pipe could also be placed in casings, especially where a leak may cause damage to the surroundings or where pressure and ground deformation may cause damage to the pipe.
Source: European commission

August 24, 2018

Confined space fatality

Confined space fatality – Sharp LadyThe Isle of Man Ship Registry has published Casualty Investigation Report No. CA118 on a confined space entry fatality that occurred on a crude tanker. The incident occurred after discharging crude oil. Equipment was lost at the bottom of a tank. It was decided that once the discharge was finished and crude oil washing completed, the equipment should be retrieved before loading the next cargo into this tank, to avoid any potential damage to the ship’s equipment.

The Chief Officer and Cadet entered the cargo tank after an enclosed space work permit and risk assessment had been completed. When the Chief Officer and Cadet reached the bottom of the cargo tank they felt debilitating effects of hydrocarbon vapour present at the lower level of the cargo tank. Both the Chief Officer and Cadet attempted to activate their Emergency Escape Breathing Devices (EEBD) and exit the cargo tank.
The Master observed the Cadet in difficulty and quickly entered the tank, ignoring the advice of a fellow crew member. The Chief Officer successfully exited the cargo tank but the Cadet had collapsed unconscious on the tank bottom. When the Master reached the tank bottom to aid the Cadet he was overcome by hydrocarbon vapour and collapsed.
The alarm was raised and a rescue was quickly initiated. The Master and Cadet were retrieved from the bottom of the cargo tank and brought to the main deck where first aid was administered. The report concludes that the Master died and the Cadet was injured as a result of entering the cargo tank containing a concentration of hydrocarbon vapour at the bottom of the cargo tank. The ship’s safety procedures for enclosed space were not fully complied with and the risk posed by the hydrocarbon vapour measured in the cargo tank was not appreciated by those involved in the tank entry preparations.
The report also concludes that opportunities were missed on board to stop the tank entry by several crew members and that the death of the Master could have been prevented had the safety procedures on board been followed in full.
The full report can be found at gov.im/lib/docs/ded/shipregistry/formsdocs/reports/casualty/iompg12.pdf

Source:IMCA

August 18, 2018

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

August 5, 2018

Level gauge and Bromine Transportation incident

Mixed acid charging in the reactor was in progress. Level gauge of mixed acid measuring vessel broke and mixed acid splashed on the body of two employees, injuring them seriously. Root Causes: Inadequate preventive maintenance, Employees not aware about potential hazard involved in the operation.

Transportation of Bromine carried out in glass bottle having 3 Kgs capacity in wooden box by goods vehicle. During transportation few bottles broken & started leaking. Due to leakage near by area affected with bromine gas. People around the area were affected due to inhalation. Root Causes: Inadequate packing of bromine bottle. Untrained driver.

Courtesy: A.G.Shingore, National Safety Council