San Bruno 30" Natural Gas Transmission Line, -FAIL- 10

[itsmoked]

This is just a notice to the folks who haven't heard about the recent pipeline disaster in San Bruno California. The San Francisco airport is in the small town of San Bruno.

http://www.cnn.com/2010/US/09/10/ca...paign=Feed:+rss/cnn_latest+(RSS:+Most+Recent)

http://www.mercurynews.com/ci_16051111?nclick_check=1

Keith Cress
kcress -

http://www.flaminsystems.com

 

[rasevskii]

There is extensive coverage in the San Francisco Chronicle website SFgate.com

It is now thought by some that the fault was caused, possibly, by sewer replacement work in 2008 which may have damaged the 30 inch HP gas transmission line at the corner of Glenview and Earl Streets in San Bruno. The sewer work had to pass under the gas line. Some commentators have posted a google street view that clearly shows asphalt patches near the gas line. Residents had complained of gas oders for weeks previously, but no action was apparently taken.

The gas line was built in 1948, some say 1956, at that time possibly in open country before the subdivision was developed.

This raises questions as to why it was allowed to build houses only a few tens of feet away from the line.

One view is that the gas leakage was into the sewer main which had to be only vented via house vents, manholes would have had new sealed covers to avoid I and I as this was not a combined sewer (no stormwater). My opinion only.

Another commentator mentioned that the pipe was blown out of the ground, indicating an explosion from below. 40 feet of pipe were ejected, the fire crater was 167 feet long, per one report.

rasevskii

 

[itsmoked]

I have problems with the, "reports of gas odor and nothing was done". PGE immediately checks any and all reports of leaking gas and I would expect major attention when it's reported around a transmission line that is ranked as one of their most dangerous.

Time will tell I suppose.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[MJCronin]

From the wall St Journal:

"SAN BRUNO, Calif.—The ruptured natural-gas pipeline that exploded and destroyed 58 homes in the San Francisco suburb of San Bruno contained a longitudinal seam and numerous welds indicating it had been made from many small segments of steel pipe—an unusual configuration—federal investigators said Saturday"

http://online.wsj.com/article/SB100...8.html?mod=WSJ_hpp_MIDDLENexttoWhatsNewsThird

I bet that there was damage done the this 40-50 year old line and an inadequate repair during the sewer work.

You know how organizations work.......ummmm....PG&E was very busy at that time......we meant to go review the low-bid contractor's work....they filled in the hole before our inspectors got there......they ran out of approved weld rod....so they used coat-hanger wire.

I can see the MBAs making excuses now......

What I truly want to know is this:

In the USA, how many other 50 year old high pressure mains run through neighborhoods with families, women and children ?

To what standard and HOW OFTEN ARE THESE MAINS INSECTED ?

DON'T THE PEOPLE WHO LIVE ABOVE THESE MAINS HAVE A RIGHT TO KNOW ABOUT THE DEADLY THREAT UNDER THIER PROPERTY ?

ANYBODY ?????????????????????????????????????????

-MJC

 

[rasevskii]

Well, it seems that the sewer replacemrent was done by trenchless technology involving pipe bursting of the old sewer line. Old diameter 6 inch, new PVC liner 10 inch. Unlikely that the old line in Earl Street was only 6 inch dia. Distance between sewer and HP gas line...? Was anything inspected...

Should be interesting...

rasevskii

 

[pmover]

MJC,

i find it difficult to believe that an operating would casually treat/dismiss or otherwise a "known" or needed repair on a HP gas transmission P/L in a HCA. if so, then hopefully the responsible people are prosecuted to the fullest extent possible.

"In the USA, how many other 50 year old high pressure mains run through neighborhoods with families, women and children ?"
There are many and they are required to be inspected IAW PHMSA 192.
(

http://ecfr.gpoaccess.gov/cgi/t/tex...760c86d446d934ba;cc=ecfr#49:3.1.1.1.4.4.9.16)

I know of several installed before WWII and these pipelines are still in operation.

"To what standard and HOW OFTEN ARE THESE MAINS INSECTED ?"
see previous answer . . . + ASME B31.8 & other associated stds.

"DON'T THE PEOPLE WHO LIVE ABOVE THESE MAINS HAVE A RIGHT TO KNOW ABOUT THE DEADLY THREAT UNDER THIER PROPERTY ?"

you need to understand that many pipelines were built long before the population swelled to current levels; thus, development in areas close to pipeline ROWs. so, when people build near pipelines (transmission or otherwise), there right to know is dependent upon the survey data they obtained before they purchase of property. Also, when people/organizations plan to develop near p/l's then the operating company is most likely well-informed either by notification or when aerial patrols are conducted.

hope this helps.
-pmover

 

[BigInch]

Third party damage is responsible for about 75% of all pipeline ruptures.

Inspection is required by Federal Law for Interstate Pipelines - those Covered by CFR 49 Part 192.

Inspection is also required for intrastate pipelines by all state laws that I've read (but I haven't read all of them).

Gathering system pipelines, except in federal offshore areas, are seldom regulated at all.

Maximum Interval between Patrols
Patrol Frequency for Natural Gas Transmission Pipelines

Characteristics of Area Consisting of 220 yards of 1-mile Length of Pipeline described by Cat I, II, III

(Cat I) Any location having fewer than 46 buildings intended for human occupancy

At Highway and RR Crossings At All Other Places
7.5 months; but at least 15 months; but at least
2 each calendar year. 1 each calendar year.

(Cat II) Any location having 46 or more buildings intended for human occupancy or where the pipeline lies within 100 yards of a building

At Highway and RR Crossings At All Other Places
4.5 months; but at least 7.5 months; but at least
4 times each calendar year. 2 each calendar year.

(Cat III) Any location where buildings with four or more stories above ground are prevalent

At Highway and RR Crossings At All Other Places
4.5 months; but at least 4.5 months; but at least
4 times each calendar year. 4 times each calendar year.

The problem with those regulations is that the method consists of patrol and visual site inspection and does not attempt to evaluate the pipe, which will be buried underground 99.999% of the time.

If the patrol misses any construction activity being conducted along the RoW, there of course can be high potential for damage. Future inspections should take careful note of any patches, dead bushes, deep marks or gouges in surrounding curbs, etc. and a further more detailed investigation undertaken, but I believe that such measures are seldom sufficient, if accomplished at all.

Pipelines are required to upgrade the area class and make alterations to the pipe design when any area classes change, but there can be a significant number of changes needed to finally jump class, so that can leave gaps in the safety level required in the prevalent area class verses what might be actually happening within some part of the area. I.e. should safety requirements really be any less of a concern, if there happened to be 45 houses in the area rather than 46. Or possibly even 1 house, if it happened to be your house?




"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.

"Being GREEN isn't easy." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

 

[JLSeagull]

When buying a house the survey would show easements and property might have deed restrictions related to a pipeline on that lot. Pipeline markers are normally located at streets and periodically along the line. Still it is possible that some of the general public would be unaware of a pipeline in their neighborhood.

I have a crude pipeline in the back yard of my 31 year-old home; closer to 6 NPS than 30 high pressure gas. I don't know if the crude line is in operation or not.

Perhaps rather than operating, it seams reasonable to replace a 30-inch high pressure gas pipeline that is over 50-years old. However I bet that replacement would entail lots of legal action. Regardless expect to hear plenty about this over the next few years.

 

[rasevskii]

JLSeagull:

Hardly anyone in a neighborhood would know the existence of a pipeline, except an engineer who had interest in such things. Not likely any Real Estate agent would tell a prospective buyer or that he would even know himself.

The current other big pipeline accident of a 34 inch crude pipeline at Romeoville. Ill, runs right down the street of an industrial park, and appears to run under streets of an adjacent suburbia. Google "Enbridge Pipeline Accident" or similar. There is a pdf with a map. Search Enridge_pipeline_map.pdf (the name is spelled wrong actually)

How are pipelines marked under paved streets, what do the markers look like?

rasevskii

 

[MJCronin]

Looks like the cause might be "deadly pup pieces".....

Its tough to put 5D bends in 30 inch pipe....

http://abcnews.go.com/US/san-bruno-...n-pipelines-run-homes-safe/story?id=11628120.

Time will tell...

-MJC

 

[pmover]

JLSeagull et al,

pipelines regulated by PHMSA 192 are required to have pipeline markers identifying pipeline installations.

from:

http://ecfr.gpoaccess.gov/cgi/t/tex...9760c86d446d934ba;cc=ecfr#49:3.1.1.1.4.4.9.16

§ 192.707 Line markers for mains and transmission lines.

(a) Buried pipelines. Except as provided in paragraph (b) of this section, a line marker must be placed and maintained as close as practical over each buried main and transmission line:

(1) At each crossing of a public road and railroad; and

(2) Wherever necessary to identify the location of the transmission line or main to reduce the possibility of damage or interference.

(b) Exceptions for buried pipelines. Line markers are not required for the following pipelines:

(1) Mains and transmission lines located offshore, or at crossings of or under waterways and other bodies of water.

(2) Mains in Class 3 or Class 4 locations where a damage prevention program is in effect under §192.614.

(3) Transmission lines in Class 3 or 4 locations until March 20, 1996.

(4) Transmission lines in Class 3 or 4 locations where placement of a line marker is impractical.

(c) Pipelines aboveground. Line markers must be placed and maintained along each section of a main and transmission line that is located aboveground in an area accessible to the public.

(d) Marker warning. The following must be written legibly on a background of sharply contrasting color on each line marker:

(1) The word “Warning,” “Caution,” or “Danger” followed by the words “Gas (or name of gas transported) Pipeline” all of which, except for markers in heavily developed urban areas, must be in letters at least 1 inch (25 millimeters) high with1/4inch (6.4 millimeters) stroke.

(2) The name of the operator and the telephone number (including area code) where the operator can be reached at all times.

while the requirement is "vauge" insofar as distance between markers, the operating company will need to exercise "due judgement". for example, a pipeline across the desert SW USA (Class 1 location) with no dwellings or nearby roads will likely not have any pipeline markers. however, the ROW "may" be cleared and maintained allowing good visual observation. in class 2, 3, or 4 locations, pipeline markers are placed per the regulations; however, "some" operating companies place more pipeline markers so as to be visually observable from other p/l markers.

MJC,
i do not believe that p/l operators install 5d bends in pipe that large. they "may" have done so back when the pipeline was installed, but not these days (3D or smaller for pipe that size) simply because of the pigging requirements/operations.

believe me, the PHMSA/PGT investigators will investigate the cause, conduct further research, and institute more regulations . . .

yes, when HP pipeline rupture, it creates one heckuva roman candle, but there is ample energy sitting in the fuel tank of the vehicle you drive too.

hope this helps.
-pmover

 

[brimmer]

They should make land developers pay for the pipeline relocation if they want to develop over existing pipelines... It amazes me they let this happen, and still today, residential developments are being constructed over high pressure gas, oil, and products transmission lines. I have investigted failures at a couple of these similar scenarios...

I often target pup or tie-in locations for SCC digs (not saying this failure has anything to do with SCC). These are higher areas of residual stress which do not help matters, especially if there is 5 in row. If you have ever seen some construction crews "fit" these in, especially in 1950's era.

 

[rasevskii]

So that begs the question: Was the San Bruno pipeline actually marked? It was under a paved street (Glenview Drive) Do the markings still exist over the undamaged portion?
Were they removed/paved over when the development was built?
This would be an interesting site survey, for all similar situations...

rasevskii

 

[pmover]

rasevskii et al,

do bear in mind that there are hundreds/thousands of pipeline crossings under paved roadways/surfaces. my experience has been that a thorough engineering analysis is done for all road crossings to minimize any impact loads onto the pipeline. some crossings are cased and others are not.

brimmer,
operating companies do generally charge developers for relocating pipelines to meet the needs. bear in mind that relocating a HP gas transmission pipeline does require engineering analysis as their could be impacts to other facilities.

btw, good to hear of the target areas you mentioned . . . there are others to consider. yes, construction and inspection crews in the 1950s is certainly different than today's standards. the objective is to minimize all risks and hazardous situations.

hope this helps.
-pmover

 

[itsmoked]

I'm surprised that a transmission main was only 3ft down. I'd have guessed 6ft for more protection. Is 3ft a typical depth of transmission lines?


-------------------
How come they aren't having service problems? They've lost a 30 inch high pressure line! Why isn't there a gas shortage somewhere in the region? What diameter line would one need to supply a large metropolitan area? Say 4 million people?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[cvg]

it appears to me that the permanent pipeline markers in the street are not required by the standards since there is a damage protection program in place. Underground Service Alert (USA) one call notification is a key part of the damage protection plan and virtually all utility companies participate in the plan. Temporary marking with paint is about all you can expect to see and will only be done when a contractor calls in a request for marking.

 

[MTPipeliner]

30" depth of cover is the minimum for newly installed lines, but you aren't required to maintain 30" cover. It could be reduced because of farming, grading, etc.

I would say that anywhere from 30" - 60" of cover is pretty normal, with a handful of lines being deeper.

I would imagine that there aren't service interuptions because it isn't winter, so the load isn't at a peak level. (Assuming that the primary load is residential heating). They may have curtailed industrial customers.

 

[rasevskii]

cvg:

In fact, tracing the San Bruno line northwards, up Glenview Drive, using Google Maps and Street View, there are only USA markings seen in the streets. There are two 90 deg bends, then it passes crosswise under Sneath Lane, through an empty lot, (no house could be built there on top of the pipe) under a basketball court, then through 10 or more back yards (off street) before reaching a valve station in a fenced area....The route is easily seen by an expert...

I hardly imagine many of the homeowners/renters have any idea about this...

Hard to imagine this line ever going back into service in this environment on this routing.

rasevskii

 

[DLite30]

Here's your answer to your right to know...

http://www.npms.phmsa.dot.gov

Locations of underground pipeline or facilities is not a secret the big bad companies are keeping from you. But no one comes knocking on your door to remind you that there's a pipeline in your backyard, radon in your basement, acid in the rain, or that the sky is going to fall on your little head. State/Fed Regulations however stiff and ridiculous they may seems do try to, in my opinion, balance both the operating requirements of the company in terms of inspection, monitoring, maintenance, and repair, and overall risk mitigation to the general public.

High pressure gas lines, large and small, run in all sorts of places you would never expect...next to schools, through mall parking lots, in back yards of million dollar homes.

It's an absolute trajedy that this happened in a location such as this. PG&E should be liable for every dollar those people are out.

I'm don't doubt that the line will go back in service, but it won't be next week and not with out a load of hydro testing or smart pig runs or maybe both.

 

[itsmoked]

Thanks PatrickR.

Keith Cress
kcress -

http://www.flaminsystems.com