Many individual measures result in a convincing sustainability concept. PFINDER has been making this consistently visible with its own logo since 2015: This is GREEN NDT. In concrete terms, this means using test equipment for magnetic particle and penetrant testing with low hazard potential through to label-free and environmentally friendly products. And this with uncompromising quality and technical performance for all PFINDER products.

Waste water is produced during the intermediate cleaning of the penetrant testing processes. If highly biodegradable penetrants are used and the wastewater has not been contaminated by the process, it can usually be discharged into the sewage system without pre-treatment. PFINDER has been offering suitable products for this purpose for over 20 years. The official approval required for this procedure has almost always been granted without exception. However, the use of environmentally friendly testing agents can also eliminate considerable investment and operating costs. At the same time, it is an active contribution to reducing harmful effects on the environment.

The note "Harmful to aquatic organisms" is a formulation from the safety data sheet (section for "environmental information" under "general information"), which refers to the respective water hazard class (WGK). The WGK classification of a test agent and the associated information in the safety data sheet always refers to the test agent in the container / delivery condition. The biodegradability and corresponding expert reports refer to a defined concentration of the test agent in the wash water of the test process. A WGK and other "environment-related information" do not necessarily allow conclusions to be drawn about the discharge capacity of the wash water containing the test agent.

Magnetic particle testing is generally regarded as a non-destructive method for detecting surface defects. Inhomogeneities that lie just below the surface can also be indicated. Magnetic particle testing can be carried out on all ferromagnetic materials with a magnetic conductivity µ>100. Ferromagnetic materials are all types of steels and their alloys and cast iron. Austenitic materials are the exception.

PFINDER provides the following products for magnetic particle testing: - fluorescent magnetic particle testing agents for testing under UV light - black magnetic particle testing agents for testing in daylight - concentrates for the preparation of a magnetic particle suspension for testing under UV light or under daylight conditions - white background color for testing with black magnetic particle testing agent - testing oils and cleaners for magnetic particle testing - accessories for magnetic particle testing

Fluorescent magenta powder testing agents are used when the tested components are assessed with the aid of a UV radiation source. In a dark environment (</= 20 lux), with the aid of a UV radiation source (>/= 10W/m²), the fluorescent dye with which the iron oxide particles are coated is excited and made to glow. Black or other colored magnetic particle testing agents are generally used for magnetic particle testing under daylight conditions. A very thin layer of white background paint is applied to the surface to be tested in order to maximize the contrast between the surface to be tested and the black magnetic particle suspension. Furthermore, colored dry powders are often used to test very hot components. The maximum temperature at which such a magnetic powder can be used must be specified by the manufacturer. However, dry powders have a lower detection sensitivity for fine surface inhomogeneities.

Subject to sample testing in accordance with EN ISO 3452-2, there are various other properties that characterize a user-friendly penetrant, e.g. easy removal from rough surfaces, safe handling due to the fact that the agent is label-free, odourless and environmentally friendly, such as biodegradability.

The removal of excess penetrant must be done in such a way that the penetrant remains in the surface defects. An approved intermediate cleaner can be solvent-based or simply water. If water is used for removal, it can be applied by wiping, dipping or spraying.

"The developer is used to bring the penetrant remaining in a defect to the surface so that the defect is then visible to the human eye. The PT test is usually carried out using a developer. Only in exceptional cases, and after tests have shown that a PT test without the use of a developer produces at least the same results as a PT test with a developer, can the PT test also be carried out without a developer. However, this must then be agreed between the two parties (client/contractor)."

A UV radiation source is used in magentic powder and penetrant testing when fluorescent test agents are used.

"For magnetic particle and penetrant testing, the illuminance at the test surface during the inspection must be < 20 lux and the irradiance, measured at a distance of approx. 40 cm, must be at least 10 W/m². To remove excess penetrant, as during intermediate cleaning, the illuminance must be < 100 lux and the irradiance at least 1 W/m². Furthermore, the UV radiation source must have its maximum intensity at 365 nm + 5 nm and a full width at half maximum (FWHM) of 30 nm. It must also be ensured that light, whether visible light or from the UV-A source, which hits the tester's eye directly or indirectly, is kept to a minimum."

Ultraviolet (UV) radiation, which covers the wavelength range from 100 nanometers (nm) to 400 nm, is the most energy-rich part of optical radiation. UV radiation is not visible to humans and cannot be perceived by other sensory organs. Due to its physical and biological properties, UV radiation is further subdivided into UV-A/B/C radiation. UV-A radiation is directly adjacent to visible light. UV-C radiation borders directly on the range of ionizing radiation. The shorter the wavelength, the higher the energy of the radiation and the more damaging its effect. Only UV-A radiation should be used in fluorescent magnetic particle or penetrant testing applications.