Authored by: Rimkus Forensic Services Marketing Team
The U.S. Consumer Product Safety Commission (CPSC) report estimates that fatalities, injuries, and property damage tied to consumer product incidents cost the nation more than $1 trillion annually. When an appliance or piece of equipment fails and causes injury, property loss, or business disruption, litigation frequently follows.
Product failure investigations apply physical evidence review, laboratory analysis, and structured root cause methodology to determine what failed, how it failed, and what factors contributed. Attorneys representing plaintiffs, defendants, or subrogating insurers rely on these findings to evaluate causation and build case strategy.
This article covers the failure mechanisms investigators evaluate, the standards that govern different types of failures, how defect classification shapes case theory, why evidence preservation affects litigation outcomes, and what determines whether resulting expert testimony survives an admissibility challenge.
Key Takeaways: Product failure investigations in litigation
Product failure investigations apply engineering analysis and forensic methodology to determine how and why appliances or equipment failed. Attorneys use the findings to evaluate causation, assess expert testimony, and shape case strategy.
What shapes the scope of an investigation:
- Defect classification (design, manufacturing, or warning) shapes the technical questions investigators pursue
- The standards that apply depend on the failure mechanism; fire-specific standards do not govern every product failure
- Evidence preservation timing can affect which failure hypotheses remain testable
What attorneys should evaluate in the findings:
- Whether the investigation methodology will withstand a Rule 702 or Daubert challenge
- Whether alternative failure hypotheses were tested and documented
- Whether the expert’s qualifications match the specific failure mechanism at issue
Rimkus supports product failure litigation with forensic engineering across mechanical, electrical, and materials disciplines. Contact us to discuss a specific matter.
What is a product failure investigation?
A product failure investigation applies a structured forensic process to determine how and why an appliance or piece of equipment stopped performing as intended. The investigation combines engineering principles, laboratory analysis, and field examination to trace a failure back to its origin.
The scope generally centers on consumer and commercial appliances, such as ranges, water heaters, dryers, and electrical devices, along with installed product systems such as HVAC units, standby generators, and integrated fire suppression components. Root cause analysis distinguishes the failure event from the failure mechanism.
A water heater that damages a property is the event. A dry-fire condition, a corrosion-related perforation, or a defective fitting may be the mechanism. That distinction helps investigators identify which components and conditions require further evaluation.
What types of appliance and equipment failures occur?
Failure mechanisms generally fall into four categories: electrical, thermal, material, and mechanical. Each produces distinct physical evidence and may call for different analytical tools.
Electrical failures include arc faults, high-resistance connections, short circuits, and overloads. Most resolve as equipment damage or malfunction, though a subset progresses to ignition, which shifts the applicable standards discussed below.
Thermal failures involve control malfunctions, dry-fire conditions, or thermal runaway in battery-powered equipment. As with electrical failures, most thermal failures cause equipment damage rather than fire.
Material and corrosion failures affect gas distribution components, evaporator coils, plumbing fittings, and heating elements. Corrosion and material fatigue commonly cause failures with no fire risk at all, including slow leaks and gradual structural weakening of components.
Mechanical failures include freeze rupture, bearing wear, and explosive overpressure. These failures often produce distinct fracture surfaces and deformation patterns that materials testing can help characterize.
What standards govern a product failure investigation?
The standards and methods that apply depend on the specific failure mechanism, not the product category alone. Treating one framework as universal risks a methodology that will not hold up to scrutiny.
When a failure involves fire or explosion, NFPA 921 provides a widely recognized, systematic methodology for developing and testing origin-and-cause hypotheses, and NFPA 1033 sets qualification requirements for fire investigators. Both frameworks apply specifically to fire and explosion investigations, and their applicability outside that context is limited.
For failures that do not involve fire or explosion, such as ordinary mechanical wear, corrosion, plumbing, or non-fire electrical malfunctions, investigators typically rely on discipline-specific engineering methods and ASTM International standardized test protocols suited to the material or component at issue. Manufacturer specifications, service literature, and applicable product certification standards also commonly inform the analysis.
Courts generally expect the investigative methodology to match the failure mechanism under examination. An investigation that applies fire-investigation protocols to a non-fire mechanical failure, or the reverse, may face a stronger admissibility challenge regardless of the investigator’s underlying qualifications.
How does defect classification shape the investigation?
Product liability allegations commonly involve design defects, manufacturing defects, or inadequate warnings, though the technical investigation should begin with the physical failure and available evidence rather than a presumed legal category.
A design-defect theory concerns whether characteristics of the product’s design contributed to the reported failure. Depending on the applicable legal framework, the technical evaluation may consider design requirements, foreseeable operating conditions, risk controls, and potential alternative designs.
A manufacturing-defect theory concerns whether a particular unit departed from applicable specifications or expected production characteristics. Investigators may compare the failed unit against drawings, specifications, quality-control data, and appropriate exemplar products.
An inadequate-warning theory concerns whether the product’s instructions or warnings appropriately addressed relevant hazards and reasonably foreseeable uses or misuses. That evaluation typically draws on expertise in warnings and human factors, product use, and the specific circumstances of the incident.
How misuse and foreseeable use factor in
Not every product failure traces to a design or manufacturing defect. Investigators also evaluate whether user error, improper installation, or maintenance practices that deviated from manufacturer specifications contributed to the failure.
This analysis can help distinguish product-related failure mechanisms from installation, maintenance, or use-related factors. When misuse is at issue, investigators typically evaluate actual use conditions, product instructions, and known operating limits without assuming any single factor independently establishes causation.
How do investigators conduct a product failure investigation?
Root cause methodology generally follows a similar sequence regardless of discipline: problem definition, data collection, hypothesis development, hypothesis testing against the physical evidence, and consideration of reasonable alternative explanations. In fire and explosion matters, NFPA 921 provides a widely recognized structure for that sequence.
Investigators compare each hypothesis against the available evidence and determine which are supported, contradicted, or unresolved. Conclusions generally should not rest on the absence of evidence alone. An investigator typically identifies a cause only when the evidence supports that conclusion to a reasonable degree of professional certainty, the same standard that fire investigation methodology and every other discipline apply.
Materials testing and laboratory analysis
Materials testing extends the investigation into the laboratory. Scanning Electron Microscopy (SEM) can reveal material microstructure and failure mechanisms at high magnification. Fourier Transform Infrared Spectroscopy (FTIR) can identify material composition, and metallographic examination can document crack propagation, corrosion patterns, and manufacturing-stage defects.
Testing generally proceeds from non-destructive to increasingly invasive analysis. Visual examination and photography occur first, preserving the evidence’s as-found condition. Non-destructive methods, such as X-ray radiography or ultrasonic inspection, may follow before disassembly, and destructive sectioning and sampling occur last, once earlier findings inform how the evidence is consumed.
Once evidence is altered, earlier stages cannot be reconstructed for review by other parties, a limitation that matters directly to opposing counsel’s ability to conduct an independent evaluation.
Why does evidence preservation matter in litigation?
Evidence relevant to a product failure claim may be altered, discarded, repaired, or returned to service soon after a loss. Attorneys and their clients typically consider early preservation important once causation is unresolved or third-party involvement is suspected.
NFPA 921 provides guidance for systematically investigating fires and explosions, and applicable ASTM standards may guide the examination, collection, labeling, and testing of physical evidence more broadly. When invasive or destructive examination is planned, the investigation team should consider appropriate documentation, notice, and opportunities for other parties to participate, based on the circumstances and applicable rules.
What are the spoliation risks?
Loss, destruction, or material alteration of relevant evidence may limit the ability of investigators and opposing parties to evaluate alternative failure hypotheses. The potential legal consequences, including sanctions or adverse-inference instructions, are fact- and jurisdiction-specific and should be evaluated by qualified counsel.
When a matter may support third-party recovery, preserving the relevant product, components, photographs, and testing records is often material to a complete technical evaluation. Preservation obligations and the consequences for noncompliance vary by jurisdiction and the circumstances of the case.
How do investigation findings shape litigation strategy?
The value of forensic findings often depends on how clearly the physical evidence, failure mechanism, and contributing factors connect through documented engineering analysis. Attorneys use those findings to evaluate causation theories, prepare expert disclosures, and assess the strength of a claim or defense before committing resources to litigation.
Subrogation and third-party recovery matters
Some matters arise through insurance subrogation, the right allowing an insurer that has paid a claim to pursue reimbursement from the party that caused the loss. Attorneys handling these matters evaluate the failure mechanism, product condition, installation, maintenance, and use to determine whether pursuing a third party is warranted.
Early evidence preservation and thorough forensic documentation allow the technical conclusions to be independently evaluated by the opposing party’s own retained experts. When the evidence points to a recurring production or component issue, the findings may also warrant evaluating other units, lots, or related incidents.
The role of expert testimony and Daubert challenges
Courts evaluate expert testimony in product failure cases under Federal Rule of Evidence 702 and the Daubert standard. The rule, amended in 2023, requires the proponent to show it is more likely than not that the testimony rests on sufficient facts, reflects reliable principles and methods, and applies those methods reliably to the facts of the case.
The Daubert framework evaluates several non-exhaustive factors: whether the theory can be and has been tested, whether it has been subject to peer review and publication, its known or potential error rate, the existence of standards controlling its application, and its general acceptance within the relevant field. This gatekeeping standard applies to technical and engineering testimony as much as to scientific testimony.
Attorneys preparing to disclose or challenge an expert typically examine whether the investigator’s chosen methodology matches the failure mechanism at issue, whether alternative hypotheses were tested and documented, and whether the expert’s qualifications align with the specific discipline involved. A mismatch between methodology and failure type, such as applying fire-investigation protocols to a corrosion failure, is a common point of attack on cross-examination.
How does methodology shape outcomes in product failure litigation?
Product failure investigations connect engineering analysis to legal outcomes through a disciplined, standards-based process matched to the actual failure mechanism. Defect classification, evidence preservation, and standards selection each shape downstream decisions from case theory through expert disclosure and cross-examination.
Complex product losses can raise overlapping mechanical, electrical, materials, and installation questions, and the standards governing each may differ within a single matter. Rimkus offers expertise in mechanical and electrical engineering, fire and explosion science, and materials testing across forms of dispute resolution.
Contact Rimkus to discuss a product failure matter.
Frequently asked questions about product failure investigations
How long does a product failure investigation typically take?
The timeline depends on the complexity of the failure, the condition and availability of the evidence, and whether laboratory testing or destructive examination is required. A limited single-component examination may conclude quickly, while a multidisciplinary investigation involving extensive testing or coordination among several parties’ experts may take substantially longer.
What is the role of exemplar products in a product failure investigation?
An exemplar is an intact comparison product sufficiently similar to the failed unit for the intended analysis. Before relying on an exemplar, investigators typically evaluate differences in model, production date, components, service history, and condition that could affect the comparison.
How does root cause analysis affect case strategy?
Root cause analysis can help attorneys determine whether a failure traces to a third-party defect rather than normal wear or user conduct, often the threshold causation question in product liability and subrogation matters. Findings that connect a specific failure mechanism to a defined defect category can help evaluate the strength of a claim before committing resources to litigation.
This article is intended to provide general information and insights into prevailing industry practices. It is not intended to constitute, and should not be relied upon as, legal, technical, or professional advice. The content does not replace consultation with a qualified expert or professional regarding the specific facts and circumstances of any particular matter.