Quality is not a coincidence:

Since nearly the complete production takes place in-house, Niessing is audited at regular intervals by independent bodies (SLV Duisburg, RAL Quality Association).
The very well-trained and highly-qualified staff at Nießing assure a high standard of quality throughout.

Approvals:

	Nießing is certified to DIN EN ISO 9001:2015 with the following scope: Distribution, design, manufacturing and erection of exhaust gas and sound proofing systems, stainless steel/metal construction
	Welding specialist certified by TÜV Nord in accordance with DIN EN 1090-1 for load-bearing components and DIN EN 1090-2 for construction kits for steel structures up to EXC3
	RAL Seal of Quality for steel chimneys, Seal of Quality Steel Structural Engineering Quality Association
	Since the end of 2013 Nießing carries the approval "Sicher mit System" ("Systematic Safety") concerning the occupational health and safety management system (AMS). Issuer is the insurance association for the wood and metal working industries.
	Nießing has been certified by TÜV NORD 2015 as a manufacturer of pressure equipment, see >> certificate

Apprenticeship:

Document of the IHK Dortmund 2014 for best apprentice 

Document of the IHK for special training performance 2017 ("Karriere mit Lehre – die Besten")