Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Pipeline Fire near Houston, TX 6

StressGuy

Mechanical
Apr 4, 2002
477
This was quite the hot topic for those of us in the Houston area yesterday:

La Porte Pipeline Explosion

It ended up being a case of an out of control car from the adjacent Wal-Mart parking lot drove into the right-of-way, crashed through the enclosure fence, and broke the line.

It made for an impressive sight. ABC News Video Story

I'm sure the pipeline companies are going to reevaluate how they secure these valve stations near populated areas. While street view shows that the right-of-way was pretty well protected by bollards and heavy fencing from the adjacent Spencer Highway, there really wasn't anything similar along the shopping center parking lot side.



Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.
 
Replies continue below

Recommended for you

Like i said before, the probability of this is so low, it indicated there would be some factor unrelated to pipelines.

Its an out of control car thing. Nothing to do with pipelines. A cliff or bridge abutment would have served equally as well, except for the additional heat of combustion.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 
Anti-lock brakes do take control. A recent addition to automation has been to give priority to the brake pedal over the accelerator pedal so that if both are pressed the accelerator pedal no longer works. Toyota was criticized for not having this when the wrong sized floor mat trapped the accelerator pedal. Neutral was available but the driver didn't use it.

The question for automobiles isn't so much for this exact problem, though it does expose how vulnerable the system is to terrorism or vandals, but that answers to this exact problem also solve a myriad of other similar problems, such as drunk drivers going down the wrong ramp and head-on into highway traffic. No need to take over steering, just shut off the motor and let the car coast as soon as it's on the ramp, possibly using the anti-lock system to stop the car.

There are also a large number of drunks and sleep-deprived people who fall asleep or otherwise unconscious. Like this situation, there was a case where a woman was essentially cut in half by a guy who knew he'd had seizures but continued to drive anyway. No need to steer; just stop the car from going.

Recall that airbags initially killed a small number of people, though under circumstances that would have done considerable harm without the airbags. So now cars have systems to weigh occupants to determine if there is an adult or a child and configure the inflator accordingly. I believe some also have a distance measurement system to see how far the occupant is from the dashboard. Then, because it was annoying people to have the airbag complain that the seat-belt wasn't buckled because some bag of stuff was on a passenger seat, cars got an ignore button.

Before that, whiners complained that a seat belt would trap them in the car if it went into the water. Of course being loosely bashed around the interior of the car might make it sufficiently disabling they could not roll down a window or open the door to leave a submerged car, plus, how often is that a problem compared to getting hit by a drunk?

My favorite - expecting to be thrown clear of a crash. In practice that was usually by exiting the windshield and getting quite a bit of flesh stripped by the broken glass, but concussion and a broken neck would make flensing not-a-problem.

The other case is rolling over, where the majority of those "thrown from the car" then have the car roll on top of them as they are only thrown halfway out, producing crush injuries. None of those occupants said they were glad of not wearing a seat belt, of those who could say anything at all.

Sure, I saw one once, really strange. Car rolled about 10 times before finally coming to a halt and on the 4th or 5th roll the driver just appeared, sitting on the ground as the car continued on. I think it was a drag-race funny car, so he'd have had a helmet to stop his brains from getting sunburned. Because the contact with the ground had no relative motion the driver didn't even slide.
 
Insurers have begun calculating the financial damage caused by the devastating CrowdStrike software glitch that crashed computers, canceled flights and disrupted hospitals all around the globe — and the picture isn’t pretty. What’s been described as the largest IT outage in history will cost Fortune 500 companies alone more than $5 billion in direct losses, according to one insurer’s analysis of the incident published Wednesday.

The new figures put into stark relief how a single automated software update brought much of the global economy to a sudden halt — revealing the world’s overwhelming dependence on a key cybersecurity company — and what it will take to recover.

 
Anti-lock brakes do take control and we had to retrain people on how to drive since they were used to manually doing the ABS function by pumping their brakes during a stop.

The problem with most of the newer car automation is rather than automating a single task, the attempt is to try and automate all the tasks. Often with sensors that have worse performance in rather regular conditions, hallucinations(from spurious input) and hidden failure modes.

I'm sure that we can get there, or near there eventually but I have higher hopes for a fully automated house than car in the near future and I have noticed that most people are not running out and doing that yet as there were some really big mistakes on thermostats(loss of internet connection make the device inop) that allowed people's houses to freeze.

I will wait for the kinks to be worked out before I get this:
 
Traction control is one of those technologies evolved from anti-lock brakes. Traction control or automation of braking the spinning wheel with open differentials is a technology common in AWD autos today and some claimed 4WD autos. While it may assist in some scenarios, it totally fails in others. True mechanical locking and limited slip designs outperform traction control in most situations.

Eg. Braking the spinning wheel with traction control when trying to start in loose material on a slope is very difficult for traction control braking systems, especially if one wheel is in a depression. Typically it leads to failure as it is like dragging an anchor, rather than spinning freely. e.g. Subaru used to have one of the best AWD systems that actually transferred torque to the wheels with traction, as in a 2012 Forester. Then in 2015 Outback they switched to traction control. On sloping gravel roads the 2012 performed a lot like mechanical, whereas Outback would get stuck on same uphill gravel roads.

Point is technology often trys to replace proven technology with cheaper solution that is advertised as a replacement, but does not always provide same level of performance.

Tesla's Giga Press Die Casting large assemblies is another example, with the lithium ion battery back inside unibody structure. It is far cheaper to produce, but yields the insurance company totaling lots of autos from what would otherwise be a minor collision. Thus repair/replacement costs, and insurance premiums are much higher.
 

Part and Inventory Search

Sponsor