piping failures

[imok2]

What are the types of failures encountered in Piping?

 

[MikeHalloran]

Axial splits from water freezing inside steel pipe.

Same, copper tube.

Transverse complete fracture of nylon vacuum tube from age and/or vibration.

Perforation of steel brake line by external corrosion.

Perforation of steel hydraulic component by internal localized corrosion from a single drop of water in silicone hydraulic fluid.

...

Mike Halloran
Pembroke Pines, FL, USA

 

[metengr]

Seek and ye shall find.....................

http://www.google.com/search?hl=en&q=examples+of+piping+system+failures&start=10&sa=N

 

[SNORGY]

imok2:

Too many to list.

Here are some buzz words and acronyms to Google:

* HIC
* SOHIC
* SSCC
* temperature embrittlement
* chloride stress cracking
* nil ductility temperature
* erosion
* energy stored in compressed gas
* effects of prolonged exposure of steel to temperatures above 775 F
* creep damage
* cyclic loading and fatigue
* cathodic protection / galvanic corrosion
* effect of hydrogen sulphide on yellow metals
* piping flexibility and expansion

However, if one was to put a more academic spin on your question, you could probably categorize "types of failure encounterd in piping" this way:

* temperature related failures
* stress related failures
* chemical attack related failures
* electro-chemical related failures

or this way:

* failure due to bending
* failure due to hoop stress
* failure due to tension
* failure due to compressive stress / load (e.g. buckling)
* failure due to torsion
* failure due to shear
* failure due to impact
* failure due to excitation at natural frequency

The more I think about what might be a good answer, the more I think the question needs to be a bit more specific.


Regards,

SNORGY.

 

[zdas04]

Yeah, but in field-gathering piping the number one cause of failure is someone hitting your line with heavy equipment. Number two is a distant second.

David

 

[zeusfaber]

all the above, plus:

failure due to use of incompatible fittings (taper into parallel is a favourite)

failure due to incorrect assembly of the fittings.

A.

 

[SNORGY]

zdas04:

That is why Clients are adamant and willing to invest in the money it takes for the engineer to prepare accurate underground as-builts.

Ooops...sorry...that might have sounded bitter...

Regards,

SNORGY.

 

[stanier]

People who have not a clue about piping design designing piping systems!

 

[europipe]

I know a company where they hire electical experts for piping design.
It looks really weird at site there.
Controlvalves hanging 5 mtrs in the air, e-w and n-s 'pipebridges'(6"pipestands) at the same elevations
Hope it doesn't explode there.

 

[zdas04]

SNORGY,
When the general public (bless their hearts) has access to rubber-tired-hoes or bull dozers and doesn't feel a need to check before they dig, perfect as-builts can be worthless. I had it so bad in one field that I developed an ArcVIEW script to allow me to click on any pipe segment and it would give me an automatic isolation list--I used it about once a quarter.

David

 

[imok2]

Thanks fellas your all good engineers because most of you were so specific in your answers I just wanted to see what kind of answers I would get On a piping test the answer is
Answer : 1. Catastrophic Failure 2. Fatigue Failure I guess that's about as general as you can get EH?

 

[jte]

If that's all of the answers which are posted for the test - then the answers are wrong. I've seen plenty of cases where the piping failed to contain its fluid in a non-catastrophic manner - and fatigue was not even close to being involved. Clearly the test writer is not familiar with the term "leak before break."

jt