3 Corrosion Disasters of the Far East

Bhopal Accident - India

On the night of the 2-3 December 1984 water inadvertently entered the MIC storage tank, where over 40 metric tons of MIC were being stored. The addition of water to the tank caused a runaway chemical reaction, resulting in a rapid rise in pressure and temperature. The heat generated by the reaction, the presence of higher than normal concentrations of chloroform, and the presence of an iron catalyst , produced by the corrosion of the stainless steel tank wall, resulted in a reaction of such momentum, that gases formed could not be contained by safety systems.

As a result, MIC and other reaction products, in liquid and vapor form, escaped from the plant into the surrounding areas. There was no warning for people surrounding the plant as the emergency sirens had been switched off. The effect on the people living in the shanty settlements just over the fence was immediate and devastating. Many died in their beds, others staggered from their homes, blinded and choking, to die in the street.

It is been estimated that at least 3000 people died as a result of this accident, while figures for the number of people injured currently range from 200,000 to 600,000, with an estimated 500,000 typically quoted.

Sinopec Gas Pipeline Explosion - China

On Friday, November 22, 2013, the Donghuang II oil pipeline suddenly exploded in Qingdao in eastern China, ripping roads and sidewalks apart, turning cars over and sending thick black smoke over the city. The blast killed 62 people and injured 136 —China's deadliest spill since the benzene oil spill in the Songhua River in 2005.

 In January 2014, Sinopec published a statement on the explosion that blames worker error and corrosion for the accident; Huang Yi, a spokesman for the State Administration of Work Safety, said that the initial oil leak at the pipeline wasn’t properly inspected and that both the pipeline’s operator and local government departments bore responsibility for the explosions. The direct cause of the explosion was the ignition of vapors produced from oil leaking from a corroded under-ground pipeline when workers used a hydraulic hammer that wasn't explosion-proof, resulting in sparks that triggered the blasts. 

Fukushima Nuclear Plant Tank Leak - Japan

On March 11, 2011, a 9.0 magnitude earthquake took place 231 miles northeast of Tokyo, Japan, causing a tsunami with 30 foot waves. The earthquake and tsunami caused a full meltdown of the Fukushima nuclear plant. At the start of 2014, three miles from the plant the roads are still closed, and radiation levels are 100 times higher than normal. All four reactors are still emitting radiation. Tokyo Electric Power Co. (Tepco), the company that owns the plant, injects hundreds of tons of water daily into the highly radioactive reactors to keep them cool, but groundwater is pouring into the damaged reactors and has to be pumped out and stored. The steel tanks that are used to store the contaminated water can’t be built fast enough--400 tons of contaminated water needs to be stored every day.

In August 2013, 300 metric tons of contaminated water leaked from a storage tank. The leak, first detected on August 19, was described by Japan's nuclear regulator as the worst accident at Fukushima since the earthquake and tsunami of 2011 caused reactors to melt.

Tepco concluded that the tank leak was probably caused by corrosion around faulty seals. The Fukushima plant has more than 1,000 tanks holding in excess of 380,000 tons of water irradiated from contact with reactor fuel. About 300 of the tanks are of the same bolted variety as the leaking tank. Tepco had rushed to build the tanks out of steel, but with the salt and all the radiation, they corroded quickly. At the time of the leak, only two inspectors were checking 900 tanks at any one time, so this highly radioactive leak went unnoticed for a month.

Towers, Corrosion & Sustainability in Dubai’s Economy - Part 2

In our last notes, we discussed how a leaky basement is a recipe for disaster waiting to happen. Why? Because clearly all the elements required for an effective corrosion cell (the basic building bloc of corrosion) to easily form and self replicate are present….in abundance.

But really, how bad can this corrosion get? Is it something that will make my building collapse? Is it something to worry about? Is it something to think about? How will it affect the sustainability of the building?

Lots of questions…

For starters, let us discuss how sustainability and corrosion are interlinked. If your building can be made to last an additional 20 years by stopping corrosion, then the technology that allows you to do this is a sustainable technology. This is the link between corrosion mitigation and sustainability.

What about our leaky basement? What can we expect in terms of how bad the corrosion can get.

The biggest risk posed to any structure from corrosion would be if the corrosion were to initiate in a ‘structurally sensitive’ area and remain accelerated and localized in that area. You can imagine what this would like; a gradual but accelerated reduction of the reinforcing steel diameter in an extremely short span of time. This is the nightmare situation for any building. It happens often. I have seen corrosion of structural columns in basements in under 5 years after completion that have caused massive cracking. It’s quite ugly and frightening. What does this tell us about how bad things can get? It’s very difficult to point to a specific rate of corrosion because corrosion is mix of so many factors – electrical, electrochemical reactions, temperature, moisture, pH and much much more. So in essence, it is difficult to predict – but who is prepared to take the chance? Would you? I wouldn’t! It is something to worry about.

The thing about corrosion is that it grows and gets worse as time passes – much like a tumor would. As a matter fact, in Australia, it is nicknamed  ‘concrete cancer’ - and unless you move quickly to snuff it out, its going to destroy the building and cost you an arm an a leg.

Many owners have gone about attending to leaky basements in a strange kinda way. As soon as leak is seen, it is plugged by crack injection. Sometimes the situation is so bad that the top layer of concrete is removed and reinstated – all in the hope of …..wait for it…removing the salt chlorides. Now why would I care so much about the chlorides. Primarily because it is a corrosion initiator and when present in excess of a certain amount, corrosion is guaranteed.

If only we had a technology that would stop corrosion in an inexpensive way irrespective of how much chlorides were present! Well it exists. Cathodic Protection. In our next part on this blog, we will discuss how this technology works for basements.

3 Reasons Why Corrosion Protection is the Sustainable Way for Buildings - Part 1

In the UAE and in the region in general, the geology of our coastal cities in the Middle East require the use of pile or raft slab foundations built from reinforced concrete to be used. These very large underground structures are typically constructed in the water table. Waterproofing attempts typically fail to stop all water ingress, and the basements are often times leaky and inundated with groundwater or significant leaks. Sometimes I have seen entire basements flooded almost to the ceiling of the basement.

 The question we should be asking ourselves is, once the leaks are plugged and the water pumped out, do we still have a problem or are we in the clear?

Do we still have a problem or are we in the clear?

To be sure this is not a one liner. Let’s consider the situation. The floor is made from reinforced concrete. It is now fully laden with chlorides, even after removing all the offending water...

We certainly can’t see the chlorides, but they are there – unless you have somehow managed to miraculously to suction out the chlorides from within the concrete matrix.

With the chlorides present in party like quantities, you now have the main recipe for corrosion;

• Salt

• Water (moisture in the concrete)

• Oxygen

Unfortunately for corrosion engineers, and fortunately for owners, the initiation of corrosion is not something that you can see. If the waterproofing fails…poof….and there is a leak

If corrosion begins….there is only silence. You won’t hear anything, you won’t see anything, at least not until it is too late.

So while the owner goes about renting out his building and counting his rental income, the corrosion reaction also goes about eating away at his steel foundation.

What are the owner’s options?

 There are a plethora of remedies available. All claim to stop this phenomenon in some way or form. But to be honest there is only one method, which will in effect freeze the corrosion in its tracks. Cathodic Protection. In the next part of this blog, we discuss in more detail the corrosion problem, cathodic protection and sustainability.