Life Cycle Analyses within Infrastructure Systems and/or Structures

Part 1: Defining a Part in a Large System and its Related Critical Material


Overview:  In Part 1, we will identify a ‘material’that may cause a ‘system/structure’ to fail.  Please answer the following four questions (each is a task for you to do):

1) Identify and describe an appropriate structure orsystem of interest.

   Examples: ELN gas supply, CWU power plant, 

2) Pick and describe an appropriatepart/device/component within your structure/system. However, you must pick a part that, if it fails, will cause the system to fail or stop operating.

   Example: A bridge has reinforced columns and road decks, etc. If the columns fail, the bridge will fail.  If the road deck fails (e.g. potholes), then the road is compromised. 

3) With regard to a part causing the system to ‘fail’, you are asked to ‘rate’ the part both with regard to operation, and the system with regard to safety.  Please note that this is discussed below.  You are constrained in your choices. The part you choose must be at most an O3.  This means that if the material of the part fails, then the system or structure will be compromised.  Also, rate the system with regard to this ‘failing’ part and if it will cause the system to function in an unsafe manner.  I recommend a five-star rating system with five being ‘best’

4Select one critical material associated with your chosen part. We will apply LCA to this material.  

   Example: A bridge column is made of steel-reinforced concrete.  The associated critical material is the rebar (steel) used as the reinforcement.


Please keep your narration to one sheet of paper.  I will specifically look for a defined system or structure.  Then I will look for a critical part and how you rated its failure with regard to safety and function of the system.  Finally, I will look for a defined material.  


Part 1. Example

In this first part of our exploration into the ‘Life Cycle’ of a complex system, we should identify asystem or structure of interest (e.g. its expensive and failing….).  We have to describe it in a way conducive to preventing failure

Thus, it is up to you to select a system or structure. Both guidance and examples are available, so please do not make excuses for any lack of progress. This world does not care if you are smart or careless or deceptive. In this course you are asked to engage in good academic work. Please read on.

Guidance: please think of newsworthy items that are appropriate to our needs. For example, in the summer of 2014 a 30″ water main burst under UCLA. Twenty million gallons of water wrecked roads, card and buildings. What happened?  The pipe failed. This is a materials failure that could have been avoided. 

Another example:  In 2011 the bridge over the Missisippi river on I-35 at Minneapolis MN collapsed killing over a dozen people. I grew up in this area and my sister should have been on that bridge but for a dental appointment. Why did it collapse? There appeared to be both a design flaw at the joints (they were not big enough) and a unique loading (construction material -sand- placed on the inside lanes during maintenance). This particular failure did not result from a material degradation scenario, so it would not be a good selection for the purposes of this activity. 


In 2010 San Francisco had a 30” pipeline explode killing eight people. From Wikipedia: “In January 2011, federal investigators reported that they found numerous defective welds in the pipeline. The thickness of the pipe varied, and some welds did not penetrate the pipes completely. As PG&E increased the pressure in the pipes to meet growing energy demand, the defective welds were further weakened until their failure. As the pipeline was installed in 1956, modern testing methods such as X-rays were not available to detect the problem at that time.[3  Asyou can read: there are big problems all over our planet.

There are so many failures occurring so often that there are plenty of systems to choose.  The biggest issue we may have is obtaining information. For example, most power plant cooling towers have failed tubes. But the management does not want the stockholders or the consumers to know about it. Why?  Because fixing these towers typically costs millions, and American companies do not include or plan for these costs (typically forecast over 90 days). So the operators ‘pinch’ the tubes shut, and the efficiency of the towers decrease.  How long can this continue?  That is a good question.

More examples include all roads, bridges, rails, power transmission, pipelines and energy systems. All structures and mechanisms are fair game, and you should be thinking of how consumer items are ‘pitched’ about lifetime and service. 

Remember that Americans typically buy, use and toss products (typically into a landfill). But those in Europe and other more mature cultures typically recycle and reuse products as a norm. We, as a culture, have a hard time thinking ‘long-term’ (e.g. more than 90 day return on investment).  But as noted above: people die from these oversights.  Did you know that there is a 30” water line in Washington D.C., still in use, that was installed around the Civil War era?  Yes, it is wood….

Notes on Ratings for ‘Safety’ and ‘Operation’: 

There are some schemes already in place to help you. But it is interesting to note that there are no entries in Wikipedia for ‘Operational ratings’ or ‘Safety ratings’.  So we will do the best we can.  No amount of combinations helped me (e.g. device operation, pipeline operation, building operation, operation measures).  So how about a search engine?  Building ratings are well supported by ASHRAE’s ‘Building Energy Quotient’.  But it is specific to buildings and primarily reflects operational efficiency.  The UK has a nice assessment for pipelines ( ).  But this emphasizes management of the pipeline system.  This is all industry specific effort and does not have the ‘global perspective’ that we need.


For both of these ratings, I then suggest we create a simple assessment that is easily understood and applied, such as the one to five stars so common in our culture.


For Structural and/or System Operationswith respect to a specific parts performance, please use the following metric.  

O0, No Star = System does not work with this part.

O1, One Star = Will work once, maybe, but is expected to subsequently fail

O2, Two Stars = Will work repeatedly, in theory, but has no success history.

O3, Three Stars = Will work repeatedly with part maintenance, but has a limited lifetime.

O4, Four Stars = Will work indefinitely with part maintenance

O5, Five Stars = Will work indefinitely without part maintenance


For Safety of a structure or system: with regard to a selected part or device within that system.

S0, Zero Star: System is not safe.  The system will cause harm if the specific part fails. 

S1, One Star: System works once, but is considered unsafe and this part should not be used

S2, Two Stars: System safely works repeatedly, but part lifetime is unknown

S3, Three Stars: will work safely, repeatedly with part maintenance, but has limited lifetime

S4, Four Stars: will safely work indefinitely with part maintenance

S5, Five Stars: will safely work forever without maintenance