Explosion in boiler due to acid cleaning

Two people were killed when an explosion occurred in a acid cleaned boiler. The explosion occurred when a an ordinary halogen lamp was inserted inside. The investigation report mentions the following:
"The most likely cause of the accident was the ignition of hydrogen gas that built up in the starboard boiler steam drum. The hydrogen accumulation occurred because of inadequate ventilation arrangements to release the gas to atmosphere, as it evolved during the chemical cleaning procedure. As the steam drum door was opened, air was drawn in and combined with the hydrogen gas to produce a mixture between the hydrogen’s Lower Explosive and Upper Explosive Limits. This potentially explosive gas was not ventilated to atmosphere, nor was the confined space of the steam drum tested for toxic or flammable gases in accordance with normal practice. As the non-intrinsically safe, halogen lamp was passed into the steam drum, either the high temperature of the halogen bulb or lens glass, or an electrical spark from the lamp, ignited the gas and caused the explosion
Southampton University’s report at Annex O clearly explains how hydrogen gas can evolve when using sulphamic acid to clean steel structures such as boilers. A conservative estimate was made of the amount of hydrogen gas that was likely to have evolved through contact with the steel in the starboard boiler. This estimate, which did not consider the interaction of other possible contaminants, was based on the assumption that there was no effective ventilation and the inhibitor was 95% efficient. The report determined that, at the point of opening the steam drum, there would have been about 2.7m3 of hydrogen present, giving a hydrogen air/mix of about 55%. This is well within the hydrogen LEL and UEL range of 4 -75%, i.e. an explosive mixture existed in the steam drum"
Often heat exchangers and new equipment are acid cleaned using sulphamic acid, in chemical industries. Ensure that your personnel as well as the contractor personnel who are doing the job are aware of the hazard of hydrogen generation in the process of acid cleaning. I would like to know from readers whether they have experienced any similar incident and what are the precautions you follow.

Read the detailed incident report in this link.
 
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Molasses tank leak

A news item mentions that a molasses tank in a sugar factory in Odisha had developed a crack and molasses entered the " staff quarters" and killed three persons.
Read the article in this link.
 
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Horrible confined space incident

Two metalworkers were "cooked" inside an oven after a worker mistakenly switched it on. The news report mentions "Detectives investigating the horrific deaths in the massive oven say the pair had tried to rip the insulation off the wall of the oven and clawed at the door in a desperate bid to get free".
Ensure you follow all your confined space entry procedures, including lock out, tag out and try procedures.
Read about the incident in this link.
 
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Major gas leak from oil rig

A major gas leak from an oil rig in the North sea has been reported. The gas has not caught fire yet. The rig and surrounding ones were evacuated. The flare on the rig continued to burn but the wind direction was blowing the gas away from the flare. Read/ see the videos in these links:
Link 1
Link 2

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Fatality due to fall through removed grating

Thanks to Senthilkumar for sharing news of a fatal accident due to fall through a removed grating:
"At the filtration section of a Phosphoric Acid Plant plant maintenance personnel were lifting a 3 meter filter cloth through a removed grating at the filtration floor at 12 m height. The filter cloth was being removed every four weeks. To lift the filter cloth, the gratings are removed and fixed back every time after lifting/replacement of the filter cloth. Unfortunately the same operator who was watching the lifting activity stepped in to the open hole (of the removed grating) while talking in a radio. He died because of the fall from from 12 m height to ground level".
Removed gratings are very dangerous. During erection or maintenance stages, ensure you have proper control over them. 

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Confined space and gas detectors

Thanks to S.Selvam for sending news about an incident where the gas detector used for confined space tests was out of calibration.Read about the incident in this link.
 Another article by Concept Controls mentions the following:
'There has never been a consensus among manufacturers regarding how frequently confined space gas detectors need to be calibrated. However, manufacturers do agree that the safest and most conservative approach is to verify the
performance of the instrument by exposing it to known concentration test gas before each day’s use. This functional “bump test” is very simple and takes only a few seconds to accomplish. It is not necessary to make a calibration adjustment unless the readings are found to be inaccurate. The regulatory standards that govern confined space entry
procedures are in agreement with this approach'.
Read the article in this link.

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Lessons to learn from safety report of Railways

The Indian railways high powered committee on rail safety has published its report. There are two recommendations in the report which also apply to process safety management in India. I am quoting from the report: "There is no practice of independent safety regulation by an independent agency separate from operations. The Railway Board has the unique distinction of being the rule maker, operator and the regulator, all wrapped into one. Commissioners of Railway Safety though considered to be the safety watchdogs have negligible role at the operational level. Compliance of safety standards set by Railways for themselves are often flouted for operational exigencies. The Committee has recommended a statutory Railway Safety Authority (RSA) and a safety architecture which is powerful enough to have a safety oversight on the operational mode of Indian Railways without detaching safety with the railway operations. The Committee has also recommended measures to strengthen the present Railway Safety Commission to undertake meaningful regulatory inspections" IR suffers from ‘IMPLEMENTATION BUG’. Implementation of accepted recommendations of the previous safety committees has been a major issue. The Committee has recommended an empowered group of officers in Railway Board to pilot the implementation of the recommendations in a time bound manner with full funding. The Committee has also recommended the review of implementation of recommendations by the new statutory outfit of Railway Safety Authority under Government of India. In India, we need to make PSM mandatory and bring an independant investigating authority like the CSB. Also, the recommendations of safety audits need to be followed up. Read the full report in this link.

Capacitor failure incident

An interesting incident of a capacitor failure aboard a ship is reported.
Chemical plants use capacitor banks to improve power factor and there are lessons to learn from this incident.
Read about the incident in this link.

Fire in Chemical Tanker

A fire has been reported in a chemical tanker in Mumbai. It appears that toluene was unloaded and "stripping" operations were on when the fire occurred.
Read about it in this link.
UPDATE: An explosion has occurred in the same vessel reportedly injuring 7 petrsonnel, one critically. Read about it in this link.

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Murphy's technology laws

I came across some interesting technology laws from Murphy! The best I liked were:

1. "The degree of technical competence is inversely proportional to the level of management.
2. Logic is a systematic method of coming to the wrong conclusion with confidence.
3. Technology is dominated by those who manage what they do not understand". 

No harm intended to anyone......but it is of relevance to PSM today!!!!

Read many good ones in this link

Modifications and HAZOP's

The Management of change element of PSM requires that a PHA be carried out when carrying out modifications. The problem I see in many companies is the lack of continuity of a PHA team due to resignations and retirements. However many checklists and procedure we write, a good PHA depends on the skills of the team leader. With people moving in and out as the PHA chair, the PHA study suffers. No PHA software can replace the skills of a trained PHA facilitator. Whenever a PHA facilitator is changed, go through your facilities management of organizational change procedures and ensure that the requirements of a PHA facilitator are met.

Update on China pesticide factory explosion

Further to my earlier post on an explosion in a pesticide factory in China, a newspaper report indicates the following:
"The investigation found that a heat transfer oil spill under one of the three chemical reactors inside the factory caused a fire that heated the ammonium nitrate and guanidine nitrate in the reactor. Both compounds are used to make explosives and explode at high temperatures.
This caused one reactor to explode, triggering a second, massively destructive blast in the plant. "The blast revealed severe problems with the production processes at the Keeper Chemical factory," according to the investigation statement.
The factory was poorly equipped, had low safety standards, and most procedures require human labor, according to the statement. Further, the factory altered the raw materials and the heat transfer oil system without assessing the risk. In addition, the workers were unqualified. Most of them, including the head of the workshop, were middle school graduates without education in chemical production. "The workers had low qualifications for dealing with emergencies and did not meet the requirements for chemical factory production," the statement said".

Read the report in this link.