Boston Water main break kills workers. 4

[oldestguy]

Not an engineering failure but of interest to engineers.

Something fishy here when trench box is needed after the fatality.

http://www.enr.com/articles/40685-boston-water-main-break-floods-trench-and-kills-two-workers

 

[SwinnyGG]

Something fishy here when trench box is needed after the fatality.

How so? Seems to me that a dry trench filled with water and then vacuumed dry is likely to collapse.. and that a trench box is the way to prevent that.

 

[WinelandV]

jg,

From the article:

Two workers died in Boston on Friday afternoon after a water main break flooded the trench where they were working, according to the Boston Fire Dept.

Followed by:

As emergency responders descended on the scene, water was removed with a large vacuum before a trench box was lowered to secure the walls to prevent the trench from collapsing, the spokesman said.

Unless you're in competent rock (per OSHA classifications), you need either a supported cut (sheet pile or trench box) or an excavation with a sloped cut.

For most utility work, you're not going to get sheet piles (or a slurry wall, etc.) so a trench box being used from the outset is most likely. Which is why the box coming in after the event is strange.

 

[IRstuff]

I've only seen trench boxes once, recently, where they were installing or replacing a sewer line.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[SwinnyGG]

I would say that the vast majority of the time I've seen utilities work being performed, there is little or no reinforcement of trench walls in place. I guess I assumed that because this behavior was so pervasive, it was not a violation of any code. Guess I was wrong.

 

[cranky108]

I've seen our companies lineup of trench boxes, and it's impressive. But usually they are transported on trailers, which is why many companies might not want to use them if they can avoid them.

On the other hand, wet soil would seem to be more mobile than dry soil.

FYI, government agencies are not required to follow OSHA regulations, as OSHA is federal, and many water companies are local government. Not to say the regulations are bad or in anyway harmful, but they may not apply to local government agencies.

 

[jayrod12]

If the trench is more than 4 ft deep then as winelandv noted they must be shored or sloped. Since sloped cuts are rarely in the best interest of the project trench cages are used constantly in our area.

Essentially every utility trench that is dug here gets one since most utilities are below frost (6-8 ft)

 

[LionelHutz]

Other news reports said the rescuers were working on their knees digging out the bodies. That makes it sound like the water started flowing into the trench and caused a trench wall collapse or possibly the trench wall collapsed onto the workers and broke open the water pipe. Either way, the company also apparently has a history of safety violations and unpaid fines. Overall, a very sad case.

 

[Spartan5]

FYI, government agencies are not required to follow OSHA regulations, as OSHA is federal, and many water companies are local government. Not to say the regulations are bad or in anyway harmful, but they may not apply to local government agencies.

For what it's worth, it seems to me that municipalities are more likely to use trench boxes than private entities. If only because there is not as strong of a time=money influence on getting the work done.

In this particular instance, it was private work being done. I'd guess they were tapping the line.

Marcy Goldstein-Gleb, the executive director of OSHA's Massachusetts coalition, told the Boston Globe the company was conducting private work, not work on behalf of the city of Boston, during the pipe break.

 

[stevenal]

FYI, government agencies are not required to follow OSHA regulations, as OSHA is federal, and many water companies are local government.

As someone who works for a local government agency that experiences OSHA regulation, I call this statement untrue. You may see the application at Link

 

[SwinnyGG]

Essentially every utility trench that is dug here gets one since most utilities are below frost (6-8 ft)

I also live in an area with deep utilities because of frost. I see trenches deep enough that the workers heads are not visible, with no shoring, all the time.

A few years ago the town I lived in reconstructed the major sewer line that ran down main street. The trench they dug for that job was at LEAST 15 feet deep, 200 or so yards long, and was not shored at all. It was, however, very wide- probably 20 feet. Two full lanes of the road were excavated.

 

[JStephen]

A number of states are not under Federal OSHA and have their own systems, but generally, their rules are similar to or identical to OSHA.
I couldn't find much on the circumstances of this accident, but there are also rules relating to having access ladders to get out of a trench. Sounds like the trench was partially covered, so it may have fallen under confined space rules as well.

 

[BigInch]

Is there a number we can call when we see 15ft trenches being dug without trench boxes?

 

[oldestguy]

For what it is worth this OG used to regularly go down in test pits, when I though the ground was solid and would be safe. One time, about 10 feet down in an area of moist clay, a contractor friend there yelled for me to get the hell out. Turns out the clay had dried some and had developed vertical shrinkage cracks. Even though the side of trench was abut 60 degrees to horizontal, in came a big block of soil tipping in on its support about 5 feet down. I'm here only because of that warning. Subsequent rule, never enter a trench over 4 feet deep unless sloped well back or trench box.

 

[hokie66]

This is old, but I am sure the situation hasn't changed. Some people just don't want to learn.

https://www.cdc.gov/niosh/docs/85-110/

 

[davidbeach]

The first trench boxes I saw in use were between 1986 and 1990; it's been a while, somewhere between 26 and 30 years ago. Why is this still an issue?

 

[BigInch]

I'll bet it has something to do with ignorance and inexperience.

 

[LionelHutz]

Once you've seen a trench collapse and trap someone you'd quickly come to the conclusion that it's completely stupid to think you can "beat" a wall falling in. Fortunately, the case I saw was minor where a bit of the wall at the bottom fell in and trapped my co-workers legs and we got him out of there before it got worse. But, the trench wall was about 5' high and if some of the higher wall had fallen the day would have ended much differently.

 

[allgoodnamestaken]

Working without a trench box:

http://www.wbur.org/news/2016/10/24/south-end-trench-flood-safety

Tens of thousands of dollars of previous safety fines unpaid:

http://www.baynews9.com/content/new...y_in_fatal_water_main_break_cited_before.html

 

[JohnRBaker]

I'll bet it has something to do with ignorance and inexperience.

And let's not forget simple greed and the almighty profit motive.

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