Safety certification

Safety certification is the process of proving to a regulator that a product is safe before anyone is allowed to use it. It applies to aircraft, car braking systems, railway signals, medical devices and lifts, where a fault can kill people. The proof is usually a large set of documents, tests and records.

Here is how it works in general. The regulator or a standards body sets rules that the product must meet. The maker designs the product to those rules and writes down every requirement, every design decision and every test. An independent assessor checks this evidence and may repeat some tests. If the evidence is enough, the product is certified. After that, any change to the design, even a small software change, may need its own checking before it is approved.

The maker pays for the assessor, and the cost is a large part of developing the product. The rules also grade each part by the harm a fault in it could cause. A fault in a seat heater needs light checking, while a fault in a brake needs the strictest checking. A higher grade means more tests and more documents. A regulator may also audit the maker's way of working, for example whether every code change is reviewed by a second person. In India, different bodies handle different fields: DGCA for aircraft, RDSO for railway equipment, CDSCO for medical devices, and agencies approved under the Central Motor Vehicles Rules, such as ARAI, for vehicles.

Take, for example, the control software of an aircraft. Every line has to be traced to a requirement and to a test, following aviation standards. Consider a railway signalling system, which must be shown to fail in a safe way, for instance by turning every signal red. Say a company makes a pacemaker. Medical regulators ask for years of tests on the device itself, and then trials on a limited group of patients, before it can be sold.

This is why such industries change slowly. A new version can take months or years to approve, and old, proven versions stay in use for decades. That in turn keeps buyers with their existing makers, as described under installed base. Related pages include railway signalling, avionics and vehicle safety electronics, and tools like safety code checking help produce the evidence.

How is it different from software as a medical device rules? Those rules are one particular kind of safety certification, written for health software. Safety certification is the general idea, used in every field where a fault can cause harm.