Product quality and safety tester Intertek is in talks to buy the business assurance division of Det Norske Veritas (DNV) with a large chunk of its own shares.The deal will make the Norwegian group a "substantial" shareholder in the UK firm, which just a few days ago said the rate of organic revenue growth is slowing in its second half. Revenue at the target business, a big player in the systems certification market, is expected to be about £200m in 2009."With this acquisition Intertek would become one of the top three international systems certification providers, with the scale necessary to provide a seamless global service," it said."Intertek believes that the acquisition would facilitate attractive growth opportunities for the group."Discussions between the two companies are continuing and due diligence is under way.