LPG explosion during welding inside a pipeline

While doing welding inside a pipeline below the ground level, with LPG gas cylinder outside at ground level, there was an explosion inside the pipeline. Unable to escape, four persons inside suffered burns. One person received 87% burns.

The reasons for gas leakage into the pipeline are not known. Poor quality of hoses, not following confined work procedures (like checking the flammable atmosphere, oxygen levels, having arrangement for emergency escape, buddy system), etc can be possible reasons.

The report can be read from the link below.



http://timesofindia.indiatimes.com/city/hyderabad/Four-welders-suffer-burn-injuries/articleshow/53757037.cms

Two persons killed, three injured during LPG line cleaning

Two persons standing in front of gas piping during cleaning were hit by cleaning device at high pressure, hit the compound wall and died. There was no fire or explosion. Only mechanical impact caused the incident.
http://indianexpress.com/article/india/india-others/two-killed-in-accident-at-gails-lpg-pipeline-in-telangana/

The reason reported was nonisolation of pressurized gas supply to the pipeline, though it was assured (?). On any energized system, before working, one should do positive isolation and vent and flush the system, which seems to be not done in this case. Assurances alone will not help.

http://www.thehansindia.com/posts/index/2015-04-05/Negligence-behind-the-mishap-in-GAIL-gas-leak--142181

Person suffers burns during digging

A construction labourer suffered burn injuries while working in a trench to repair a septic tank piping. The person using a power tool to remove the damaged pipe hit an LPG line in the trench and the sparks led to fire engulfing the person. The injured with difficulty came out of the trench and rolled over the grass to extinguish flames. The person who engaged the injured was penalised for various lapses.

From the description about the incident, the lapses that come to notice are,

1. Whether any permission taken for digging where the gas lines are present. It is a widely followed safety practice to identify presence of utility lines like electrical/gas/water in the area proposed for digging and take precautions to ensure safety of the persons and property. If it is in a factory area, concerned engineer will give clearance and in case of public area, town planning engineer will give such clearance.
2. From the photograph in the weblink, service line identification marks are not visible in the area.
3. Absence of measures for preventing trench cave-in.
4. Lack of proper means of access/egress from the trench like a ladder at 30 m distance intervals.
5. Whether only one person was engaged for such work and if not what happened to other workers.
6. Absence of supervision.

Most of accidents reported are leak/fire/explosion due to puncturing of gas lines during digging.

NDTV Video of LPG Tanker explosion

There is a video of an LPG road tanker explosion occurred in Turkey. The video was captured in a cell phone camera. It shows the impact of pressure wave generated by the explosion in the form of fall of persons, light emitted during explosion, widespread damage to property and a crater in the road.
This reminds me of an incident where an LPG tanker toppled and fell on the road. Without understanding the hazard of explosion any time, passersby gathered around. Even the company officials took more than a day to put it on the road and tow away.
In another incident an ammonia tanker fell on the road. However, in this case, the road was blocked, the company officials promptly transferred the content to another vessel and cleared the area in a few hours.

Though everyone should be careful, it is the responsibility of the transporter and the manufacturer of the chemicals to ensure that transport containers are fit for road journey, the drivers know what to do in an emergency and are trained to handle the situation. Normally, the behavior of the public at large is to gather and watch. So, the driver of the vehicle, in an emergency, should caution and drive away the public to safe distance so that they are safe in case of any eventuality.

LPG GAS leak, explosion and burns

Many times it is reported in news papers that there was LPG stove explosion leading to burns / deaths. Not many people are clear whether it is the explosion of stove or cylinder or gas. Normally, the leaking gas creates flammable atmospheres and when someone tries to switch on the light in the morning or uses lighter, the leaking gas in flammable range ignites and explodes. Bursting of cylinder is a rare case which can happen only when the cylinder is exposed to external fire and contents inside are pressurised and then the cylinder explodes with fragments flying all around.

Few years back, it is reported that a fragment from such explosion killed a person on the road. Otherwise, the gas explosion causes burn injuries and deaths to occupants of the building, causes collapse of the roof, shatters window panes, doors, etc.

Simple precautions like closing the regulator after use every time, keeping constant vigil / observation when milk or other items are kept on the stove, changing the hose once in two years or as recommended by the hose manufacturer will keep safe our homes and save us from consequences.

Similar to the above, auto rikshaw drivers check the level of petrol / diesel in the tank in the darkness with the help of a lighted match stick and the vapour in the tank catches fire leading severe burns. Such news reports also appear now and then in the news papers.

Such incidents as above show that people lack even common sense and it is a big question mark about how governments, regulators, society can protect them. Because such acts not only injure these silly people but also affect nearby persons and may cause destruction to persons / property located even 50-100 m away.

Gas cylinder Explosion

Yesterday (16.01.2009 Friday), I read a news items in a local news paper with the title, which is the title of this post. It states that four persons were seriously injured due to burns in this accident. It is reported in the news paper that when gas cylinder in use has become empty,  the house owner (a gold smith, may be with both shop and house together) informed and got refil cylinder from the LPG supplier at about 1430 hours. When the family members  of the house opened the gas (stove knob ? / cylinder cap ? / regulator knob ?), the gas leaked. Seeing this, the workers in the shop put the cylinder in a water tub. Still the leaked gas (obvious, as LPG does not dissolve in water) spread around and caught fire (there can always be an ignition source for a combustible material). The fire caused burn injuries to four persons who were working in the shop. After extinguishing the fire, the other workers admitted the injured in a private hospital and informed the police. The police went to the spot and shifted the injured to a government hospital for further treatment of the persons whose condition is serious.

The above news items and similar such news items earlier always raised so many questions in me.  A few of them are,

Whether the cylinder exploded (as per the title of the news item)

However, as per the news item mentioned below the title, it is understood that the cylinder did not explode but it is the leaked gas that exploded.

- Similarly, sometimes reports appear as gas stove explosion. This also gives impression that the stove (burners) exploded. But mostly it is the leaked gas explosion.

The reaction of the persons for arresting the leak is another question in my mind.

We can't blame the persons who have put the cylinder in a water tub in this case because of their knowledge / awareness. However, it is better if the gas cylinder suppliers put stickers on the cylinder containing information like, what to do in case of gas leak / leak and fire; whom to contact; the emergency contact numbers, what checks are to be done by the receiver i) when the cylinder is received (this is normally done by the supplier / delivery boy in some occasions) and also ii) during regular use; the cylinder test date and due date for next testing by the company; instructions for the user to inform with contact numbers  if receives a cylinder after expiry date / damaged condition of the cylinder,etc. Normally, this type of information is provided on the industrial gas cylinders and similar information with more details should be made available to the domestic users.

Eariler a few years ago, when I was in my office, I received a call that outside our organization a lorry (truck) with gas cylinders was stopped because of gas leak. My self with a colleague visited the spot and found that all gas cylinders were unloaded onto the road side and also observed some white powder on a few cylinders. On enquiry with the driver of the lorry, we found that as a precautionary measure, he used the portable fire extinguisher in the lorry.  This also shows the poor knowledge of the drivers of hazardous chemicals. Though he will get licence for hazardous chemical transportation and will be renewed every year, the employers should ensure that all their staff get required training and retrained again and again. Without training, they should not be engaged in transportation at all.  Sometimes, the material brought by the driver will be different from what is mentioned on HAZCHEM information on the containers. The trained driver will ensure that correct HAZCHEM stickers are displayed on the container and this will help the others on the road also, if the driver is not in a position to take proper measures. In the drivers cabin also, the tools and personal protective equipment list and location should be displayed prominently for the same reason.

Normally, the procedure in case of gas leak is take the lorry to a less inhabitated / less crowded place atleast and cordon the area by atleast 300 m around, simulatneously inform the police and their employer and wait for instructions. In case of gas leak of a domestic cylinder in a house, inform the supplier, take the cylinder outside in to a open area (not through lift), remove ignition sources in the nearby area to the extent possible and wait for the supplier to do the needful. In the news item reported above, it appears the cylinder was put in the water tub inside the house and may the confinement of the house lead to accumulation of gas and it is not able to disperse. The ignition source is obvious as it happened in the house that belongs to a goldsmith with shop in it. Goldsmith will have fire kiln  or of such arranagement for making the ornaments. Moreover, the refill was delivered at about 1430 hours and the cylinder was handled soon for replacement as per the news item. This shows that it happened during the working hours of the gold smith shop.

Had the cylinder was put in a water tub or covered with wet blanket / cloth outside, the leaked gas could have dispersed easily and cylinder will have cooling to prevent overpressurization in case of fire nearby.

The incident of gas leak happened in my house also once a few months ago. When I replaced the empty cylinder with a full cylinder and opened the regulator knob, I found gas leaking from the cylinder nozzle. I removed the knob and placed cylinder cap and it arrested the gas leak. I opened all windows ( I stay in an apartment) informed the supplier immediately about the leak. I could not get connection to the supplier as the phone line was busy (obvious as he will be getting calls for refill bookings). My wife went to the supplier's office located at about 3 - 4 km from my house. It took about 15 - 20 minutes to reach the office as the traffic was more on the roads and by the time we tried by phone and then informed personally, more than 45 minutes time elapsed. Then, the person came about 2 hours later, checked the cylinder nozzle and replaced the rubber gasket in it. 

It may be routine call for the gas suppliers but the users will be under tremendous tension. In my case gas leaked only when connected and regulator knob is opened. If it is leaking even when the cylinder cap is not removed then imagine the plight of the people. Similarly if the leak occurs on a weekend or non-working hours of the gas supplier, then getting help is also very difficult.

Though emergency numbers are listed in the telephone directory, in emergency people will be panicky and may not remember what to do. Also, the the numbers in the directory may be old. Further, telephone directories are not published by all telephone companies. If the users are having only mobile phones, then they don't have any directory. Fortunately, now phone number 108 is available to contact in case help required when there is an emergency (fire/police/ambulance). But, how many people know this information is questionable. Only learned people with an eye on what is happening in their surroundings will know. Otherwise, there are many people who don't read news papers or look around billboards / stickers pasted at important places.

If this information and other important details as mentioned in the beginning of this article are displayed on the cylinder itself, it will be help for all the users. The information should be available in English, Hindi and the local language. Pasting of the sticker by the gas cylinder delivery agency should be made mandatory. If the agency is made responsible, then the sticker with instructions in local language along with English and Hindi can be ensured. The sticker may cost 2-3  rupees. But, this will definitely help the users. If stickers are not used and only pamphlets are distributed, users may lose them and utility can'g be guaranteed.

I will put some more information on this subject in my future posts.