When a product fails in the field, the first reaction is often to identify someone to blame. More often than not, the finger is pointed at the design engineer who created the product or the laboratory that tested and certified it. While this may seem like a logical conclusion, it rarely reflects the complete picture. Product reliability is influenced by a combination of engineering decisions, manufacturing quality, operating conditions, user practices, and environmental stresses. Looking at only one part of the chain often leads to incorrect conclusions.
The Role of the Design Engineer
A design engineer develops a product based on defined requirements, available standards, expected operating conditions, cost targets, and project timelines. Every engineering decision involves trade-offs. A product designed for indoor operation cannot reasonably be expected to survive years of exposure to extreme outdoor conditions unless those requirements were specified during development. Similarly, no engineer can design against unknown or unspecified environmental stresses. A successful design is one that meets the intended application — not every conceivable condition that might occur.
The Role of the Testing Laboratory
Likewise, a testing laboratory validates products against agreed standards, specifications, and customer-defined test plans. Laboratories do not determine how a product should be designed; they verify whether it satisfies the applicable qualification requirements. If a product successfully passes all specified tests but later encounters operating conditions that were never part of the qualification program, it does not necessarily indicate that the laboratory failed. It simply means the product was exposed to scenarios beyond the defined scope of testing.
Environmental Conditions in the Field
One of the most overlooked aspects of product reliability is the environment in which the product actually operates. Field conditions are often significantly harsher than laboratory assumptions. High and low temperatures, rapid temperature cycling, humidity, dust, vibration, mechanical shock, corrosion, ultraviolet exposure, altitude, water ingress, and chemical contamination can all influence product performance.
Electrical Stresses and EMI
Electrical stresses are another major contributor to failures. Unstable power supplies, voltage surges, switching transients, electrical noise, grounding problems, and poor power quality can damage sensitive electronics. Similarly, electromagnetic interference (EMI) generated by nearby equipment or unexpected electromagnetic environments can cause intermittent malfunctions that are extremely difficult to reproduce unless appropriate immunity testing has been performed during product qualification.
Manufacturing Quality
Manufacturing quality also plays a significant role. Even an excellent design can fail if manufacturing processes are inconsistent. Variations in soldering quality, component placement, torque settings, material substitutions, assembly errors, or workmanship defects can introduce failures that have nothing to do with the original design.
Component Quality and Supplier Reliability
The quality of purchased components further adds to the complexity. Modern products depend on components supplied by numerous vendors across the globe. Variations between production lots, counterfeit parts, supplier process changes, or premature component ageing can affect field reliability despite the product being designed correctly.
Transportation and Logistics
Transportation and logistics are equally important. Products often travel thousands of kilometres before reaching customers. Improper packaging, rough handling, excessive vibration, accidental impacts, or exposure to moisture during transportation can damage equipment long before it is installed.
Installation and Usage Conditions
Installation and usage conditions frequently determine long-term reliability. Products installed incorrectly, connected with improper wiring, mounted without following recommended practices, or operated beyond their specified limits are naturally more likely to fail. Even maintenance practices such as inadequate cleaning, improper repairs, incorrect firmware updates, or the use of incompatible accessories can significantly reduce service life.
Limitations of Qualification Programs
Another important factor is that no qualification program can realistically simulate every possible operating scenario. Standards such as environmental testing, vibration testing, shock testing, EMI/EMC testing, ingress protection testing, and reliability evaluations are designed to represent realistic conditions based on years of industry experience. However, every customer application is unique. Products used in mining, defence, aerospace, railways, renewable energy, marine, automotive, or industrial automation may experience combinations of stresses that extend beyond standard qualification requirements.
Reliability Is a Collaborative Effort
This is why successful product development is always a collaborative effort. Design engineers, manufacturing teams, quality engineers, test laboratories, suppliers, logistics partners, installation teams, and end users all contribute to the final reliability of a product.
How Envitest Laboratories Approaches Testing
At Envitest Laboratories, we view testing not as a process to “pass” or “fail” products, but as an opportunity to understand product behaviour under controlled conditions. Every environmental, vibration, shock, EMI/EMC, electrical, or reliability test provides valuable engineering information.
Final Thoughts
The next time a product fails, the question should not immediately be, “Who is responsible?” Instead, the better question is, “What combination of factors contributed to the failure?” Only through systematic root cause analysis can organizations improve designs, manufacturing processes, qualification methods, and operational practices.
Reliability is never the responsibility of a single engineer or a single laboratory — it is the result of the entire product lifecycle working together.