Air Quality

DCUK is a market leader in ventilation maintenance, ductwork cleaning and management, kitchen extract cleaning and contamination remediation services. Founded in 1998 and operating nationally from headquarters in Welwyn Garden City, Hertfordshire, the business employs 200 people. DCUK’s key customers include national hotel and leisure providers, airports, NHS trusts, universities, local authorities, and FTSE Companies.


First incorporated in September 1986, Tersus is a leading testing & inspection specialist. Tersus maintains accreditation for asbestos surveying, air monitoring and clearance testing, bulk identification and bulk sampling. In addition to these services, the business offers a completely managed service of asbestos obligations including project management and training. 

Tersus is accredited by UKAS (United Kingdom Accreditation Service) for testing and inspection to ISO/IEC 17020 and ISO/IEC 17025. Tersus also holds accreditation by UKAS to ISO/IEC 17025:2005 to sample and count fibres away from a permanent fixed laboratory in accordance with HSG 248 “The Analysts Guide”.  Fibre counting is carried out in one of our mobile laboratories, which are themselves regularly checked and inspected to comply with UKAS accreditation.  The business employs around 180 people offering a nationwide service from seven strategically placed UK offices (London; Birmingham; Brighton; Bristol; Nottingham; Sheffield).