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Hazmat 101 News - November 2004

Warning: This an Experiment

Here's how to participate in the experiment.

• Step 1: Read the information in Part One
• Step 2: Read the information in Part Two
• Step 3: Follow the instructions in Part Three

Part one: The Gist of a Message

This part is the gist of a forwarded message about tank car collapses.

Whether tank car, a tank, or any vessel, without proper venting this can happen . . .

Take a look at these pictures. (Click to open in new window. If you don't see the new window, enable popups or JavaScript.)

Here: tank car view 1

Here: tank car view 2

And here: tank car view 3

Unloading from the bottom outlet without properly venting the car collapsed this car. This could also happen with top unloading if the car is not vented. This would be about a $57-$65k loss, not to mention possible safety and injury issues to property and people.

This illustrates the magnitude of possible damage, by overlooking a simple vent valve. Some tank cars are equipped with vacuum breakers, however the majority do not have this option due to other operational and product considerations.

Another example: Plastic Bag Collapses Storage Tank

Take a look at these pictures. (Click to open in new window.)

Here: the tank after --profile view

Here: the bag and the tank

And here: the tank after -- the base

An here's the safety alert distributed with the pictures.

"Pressure Equipment Alert (PEA): Storage Tank Collapse - The Power of a Plastic Bag

"Attached are three photos, courtesy of the API showing a tank collapse as a result of drawing out of a tank when the vent valve was covered by a plastic bag to 'protect'  it during tank painting. This is the third such tank collapse that I am aware of from the exact same cause.

"Who knows how many more times this happened that I am not aware of ….

"(The second picture shows the) top of the collapsed tank where the vent is covered with some plastic…. The (third picture shows a) close up of the bottom lifting off the foundation during the collapse…. The scaffolding around the tank is for painting.

"Lessons Learned:

"1. Covering the vent valve during tank painting is fairly standard practice; unfortunately leaving it covered when drawing out of the tank is very non-standard practice.

"2. This is an expensive, embarrassing mistake that is entirely preventable by adherence to good procedures and good communications between operations and maintenance.

"3. This sort of thing nearly always results in total destruction of the tank. It is generally not cost effective to repair tanks with this extent of damage.

"4. For some, it is hard to believe that the plastic over the vent valve is stronger than the steel tank under the vacuum conditions that are created when drawing product out of the tank. Seeing is believing."

Part Two: My thoughts

This part is my reaction and thoughts about this information (AKA my 2 cents, or my opinion)

Lesson learned:

• Ignoring the laws of nature can ruin your day, plus more …
• This type of incidents can happen to any container: drum, vessel, barge, portable tank, tank etc.
• This type of incidents can happen to any material transfer. During a material transfer, material is removed (emptied, unloaded etc.) from one container and is added (loaded, filled etc.) into another container. Remember: two containers are involved.
• It can also happen when venting and breathing of containers is obstructed.

The laws of nature (I made them up!)

• In order to add material to a closed container, I must remove material, unless I want to pressurize the container. Typically, the material removed is the material already in the container, its vapor, an inert gas (nitrogen), or air.
• In order to remove material from a closed container, I must add material into the container, unless I want to put the container under negative pressure. Typically, the material added is an inert gas (nitrogen), or air.
• Temperature variations will result in pressure variations of vapor or gas contained in a tank/container.
• If I ignore the laws of nature, I could ruin my day resulting in explosion or implosion and the bad consequences that go with such an event.

This type of events are  not uncommon. When they happen, they are usually caused by the human factor (not following proper transfer procedures) or not understanding consequences of  "change . . ."

Food for thought

• What chemical transfers occur at your workplace?
• For a chemical transfer activity that occurs at your workplace, what materials are added to and removed from each container involved?
• What could happen if a material was not allowed to be added or removed during a chemical transfer activity?
• What is the probability that it could happen?
• How does the transfer method (gravity feed, pump transfer, pressure transfer, regulated inert gas etc.) affect these relationships?
• What safety features or systems can prevent or reduce the risks?
• For tanks at your workplace, think of ways where venting or breathing of the tank could be prevented. What if it happened?

Part Three: Your Thoughts

1. Write down your thoughts and reaction to this information.

2. Write down what you plan to do about it.

3. If you want, share your thought by posting at the Hazmat 101 List.