Failure analysis and forensic diagnosis
The words of failure analysis, the three conditions of water entry, the failure modes the published record supports, a six-step documented method with two worked examples, and published case studies on edge metal and a roof leak.
4 lessons · about 41 min · 14 diagrams · 2 videos
Version 1.0.0
Builds on these modules
Lessons
0 of 4 complete
Lesson 1 · 9 min · 8 slides · 7 questions
Failure analysis and forensic diagnosis: principles and terminology
The words of failure analysis; the three conditions water entry needs; why a guide written for walls still teaches good habits; oil canning as a defect that is not always a failure; and the limits of what AFS can state.
You will be able to: Tell a symptom, a failure, a defect and a cause apart, name the three conditions and the forces of water entry, explain why a leak shows up away from its entry, and state what AFS can and cannot say about a returned part.
Not startedStart →Lesson 2 · 12 min · 12 slides · 9 questions
Failure analysis and forensic diagnosis: materials, standards and design constraints
Oil canning and thin flat faces; restrained thermal movement and cleat practice; expansion by material; wind zones on the roof edge; the ES-1 tests; why a tested capacity belongs to one assembly; and corrosion rates as first-year ranges.
You will be able to: Connect each failure mode the published record supports to its mechanism and the evidence to expect, use the AFS register values for movement, read an edge-wind demand and a tested capacity correctly, and read a corrosion rate as a first-year range.
Not startedStart →Lesson 3 · 10 min · 10 slides · 8 questions
Failure analysis and forensic diagnosis: methods and worked application
A six-step documented method; what to record; tests in order of least damage and why one test does not settle it; a movement calculation; demand against tested capacity; confidence words; and the job packet.
You will be able to: Run the six-step method, document a part so another person can use the record, choose the least destructive test that could prove a hypothesis wrong, calculate expected movement, and compare an edge demand with a tested capacity or say none exists.
Not startedStart →Lesson 4 · 10 min · 10 slides · 7 questions
Failure analysis and forensic diagnosis: defects, verification and case study
Three FEMA 488 school cases and an IIBEC leak case; where to look on a coping; corrective options and what each addresses; causes outside the metal; verifying a repair; and writing a finding.
You will be able to: Read a published case and separate fact from inference, say when a cause cannot be determined, choose a corrective option by the condition it addresses, and verify a repair.
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Practical task
Build a job packet for one failed or complained-about edge part, real or described in a published report: write the problem statement, fill the evidence card, state two hypotheses with the least destructive test for each, calculate the expected movement of the piece, and write a finding with a confidence word and a verification plan.
Hand in
- A problem statement that says what was seen and where, not why, and names no person to blame
- A filled evidence card (rows A to H) with a sketch or photograph of each place you looked, and a note of what you could not see
- Two hypotheses, each with the least destructive test that could prove it wrong and what result would change your mind
- An assumptions sheet with units: metal, thickness from the order record, piece length, the temperature change you assume (labelled as assumed), and the movement it gives
- A finding using one of the four confidence words, with a verification plan that repeats the test that reproduced the problem
Rubric
| Criterion | Meets the standard when |
|---|---|
| Problem statement | It states the symptom and its location without a cause, a cost or a name. |
| Evidence | Observed facts are kept apart from interpretation, with units, and what was not seen is listed. |
| Hypotheses and tests | Each hypothesis could be shown wrong by its test, and the test is the least destructive one available. |
| Movement calculation | It uses dL = alpha x L x dT with a sourced coefficient, labels the temperature change as assumed, and does not turn the result into a joint gap. |
| Finding | It uses a confidence word the evidence supports, and says cannot be determined where evidence is missing. |
| Safety | Any roof or edge work names the fall protection in use, and no flood test is proposed without the roof manufacturer's written position. |