Water tank explosion....yes, a water tank 4

[fel3]

https://www.yourcentralvalley.com/n...tures-deadly-water-tank-explosion-in-lemoore/

This happened in my area. I am very familiar with Lemoore and its water system because twice I was at firms that served as the contract City Engineer and I have designed some elements of that water system. My first stint was long before the Well 7 site was developed. My second stint was after the well and first tank at this site had been constructed. I helped the engineer who designed the water treatment vessels and second storage tank at this site sort out some piping connections, but I can't tell you if it was the older or newer tank that just blew up and my records are in storage.

Apparently, someone was welding something to the outside of the tank and it sparked flammable gas inside the tank (that's what the City's Public Works director speculated about in an on-site interview I saw online). This tank appears to have had a good amount of water in it, so I'm having trouble understanding how a flammable gas got into the headspace of the tank. More details will certainly come in the next days/weeks/months.

============
"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

[TugboatEng]

You're missing my point. Ventilation is the key to safety especially considering most gas analyzers only test 4 parameters. As I said earlier as well, flammable gasses can also be produced during welding so continued ventilation is still mandatory during the entire process. The gas analyzer is a backup safety check to verify the performance of your ventilation.

 

[waross]

In the early years of crude oil tank farms in Northern B.C., a common death was a worker falling off of a tank
The worker would would be on top of the tank for some reason and would get a blast of H2S and become so intoxicated that he would fall off the tank.
The fall would kill him.
It's pretty hard to install a ventilation system if you didn't check for gas and you are already dead.
It was mentioned that H2S is known to occur in well water in the area.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[FacEngrPE]

I am glad you all agree that a suspenders and belt approach is necessary with confined space ventilation.

 

[waross]

When you consider the "suspenders and a belt" approach look at the trousers as the first step.
I have worked under too many "Hot Work Permits" and "Confined Space Permits" to consider a gas test to be redundant or supplementary.
I have been evacuated and seen crews evacuated too many times, despite ventilation, to consider gas tests to be redundant or supplementary.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[TugboatEng]

Waross please see Eufalconimorph's post. It explains your disagreement.

 

[waross]

You don't get it Tug.
I am familiar with the suspenders and belt approach.
Meditate on "First" and "Mandatory" as opposed to redundant.
With redundant systems, either system will provide protection.
In the case of H2S, a worker may die installing the ventilation if he has not first checked for the presence of H2S.
This is NOT redundant.
Redundancy would be two gas tests with two different gas detectors.
On the other hand, it is common to have ongoing gas checks, either with automatic monitors (Rig-Rats) or manually, while work is in progress. That I will consider as a redundancy.
However the first and most important gas check is mandatory and is not redundant to anything.
I have many times worked under "Hot Work" permits where the first, mandatory, gas check was done, but no further "Redundant" gas checks were done as work progressed.
It depends on the circumstances.
Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[dik]

When I was young and rockclimbed... I never considered the supplemental attachments as ever being redundant... redundant implies they are not necessary. Other than the Floodway gates, I don't think I've ever gone into a confined space without 'air' and testing beforehand.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[RedSnake]

I think Eufalconimorph is talking about what we in the computer and PLC world calls redundant systems or redundancy.
Meaning we copy everything to two places where all information is equal so if one server, machine or backup fails it automatically starts using the other "copy"/machine and everything keep running as usually.
It is like a safety net, backup, insurance.

Some other uses.

Redundancy is called information that repeats already established information without adding any new one.
Redundant information is therefore sometimes also called surplus information.
However, such information plays an important role in many contexts in clarifying or securing information, but can also be seen as something that takes up unnecessary space or constitutes unwanted repetition and should be reduced.
The word is also used for technical systems that, for safety reasons, have more components that can replace each other in the event of operational problems.

A word with many meanings. ;-)

Best Regards A



“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Eufalconimorph]

Yep. The classic climbing mnemonic acronyms of "ERNEST" (Equalized, Redundant, No Extension, Solid, Timely) "SERENE" (Strong, Redundant, Equalized, No Extension) and the more modern Alpine "STRADS" (Solid, Timely, Redundant, Angle, Distribution, Simple) all use "redundant" to mean a system that has multiple components wherever possible such that if any single component fails the whole system remains safe.

 

[Carlos F Molina]

I hope the real reason behind this explosion should be shared for all of us. BTW I dind´t know H2S could be flammable. tHANKS FOR POSTING ALL

apiexam.com

 

[Hoxton123]

In the UK we had an explosion in 1984 in a waterworks valve house due to methane seeping from coal seams. Unfortunately there were people inside the valve house at the time.

https://en.wikipedia.org/wiki/Abbeystead_disaster

 

[fel3]

Well, according to this report it was CH4, not H2S.

https://hanfordsentinel.com/news/le...cle_3cb6fe3d-6f14-51c1-b8c2-05d9f625446e.html

============
"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

[itsmoked]

OK.

It's SO easy to forget that real methane is completely odorless in a world filled with odorized methane. A million gallons of cold water and no smell the thought won't even cross one's mind.

I'd say a warning sign reminder on any weldable water tank would be a cheap but effective safety precaution.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[LittleInch]

For anyone not able to access.

https://abc30.com/lemoore-water-tank-explosion-deadly/10902429/

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[wayne440]

That sign should perhaps say -"odorless methane..."

 

[itsmoked]

wayne440; Excellent point!

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Demented]

Could this have been prevented by simply training on and following existing OSHA guidelines?

1910.252(a)(2)(vi)(C)
In the presence of explosive atmospheres (mixtures of flammable gases, vapors, liquids, or dusts with air), or explosive atmospheres that may develop inside uncleaned or improperly prepared tanks or equipment which have previously contained such materials, or that may develop in areas with an accumulation of combustible dusts.

1910.252(c)(1)(iv)
Hazard communication. The employer shall include the potentially hazardous materials employed in fluxes, coatings, coverings, and filler metals, all of which are potentially used in welding and cutting, or are released to the atmosphere during welding and cutting, in the program established to comply with the Hazard Communication Standard (HCS) (§ 1910.1200). The employer shall ensure that each employee has access to labels on containers of such materials and safety data sheets, and is trained in accordance with the provisions of § 1910.1200. Potentially hazardous materials shall include but not be limited to the materials itemized in paragraphs (c)(5) through (c)(12) of this section.

1910.252(a)(3)(i)
Used containers. No welding, cutting, or other hot work shall be performed on used drums, barrels, tanks or other containers until they have been cleaned so thoroughly as to make absolutely certain that there are no flammable materials present or any substances such as greases, tars, acids, or other materials which when subjected to heat, might produce flammable or toxic vapors. Any pipe lines or connections to the drum or vessel shall be disconnected or blanked.

If they had just tested the atmosphere prior to hot work.



Precision guess work based on information provided by those of questionable knowledge

 

[RedSnake]

Just from reading the text I would say none of the above paragrafs can be applied here.

1910.252(a)(2)(vi)(C) refers to tanks that hade previously contained such materials, or dust.
1910.252(c)(1)(iv) refers to potentially hazardous materials solid ones.
1910.252(a)(3)(i) refers flammable materials present or any substances.

The tank where made to contain the material water not CH4.
Not sure if gas is considered a substances though.

Maybe there is other paragraphs that might apply.

/A



“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[dik]

any confined space training I've been exposed to has always stressed the presence of toxic or explosive fumes, moreso than the actual safety code stipulated. Testing air quality was first thing on the agenda... I was surprised to learn that if someone 'goes down' you leave them and get out...

I still feel the pain from the 'dressing down' I received from taking some 'testing guys' into a confined space about 10 years back. It was confined, but not hazardous and the 'keeper' had gone for lunch... we all signed in and entered the space to take coupons for metallurgical testing on my OK. We had a monitor with us, but should have had someone at the 'entrance'. I was wrong, and should have waited.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[RedSnake]

But in this case the welder must have been welding from the outside.
And the tank was not totally empty maybe 1/4 filed with water, if it had been full of water it would probably not have happened.
And there where this inner lining, have no idea if you even can get into a tank like that to test the atmosphere or ventilate it.

/A



“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein