Without this certificate a client could refuse to accept the handover of a building from a contractor or developer.
The government's call came in a circular letter to building control bodies and approved inspectors issued by the Office of the Deputy Prime Minister on 4 April 2003.
The ODPM issued the letter after concerns that approved inspectors and building control officers were failing to ensure that newly completed buildings were airtight and complied with pressure testing requirements.
The need for contractors to pressure-test buildings was introduced under revisions to Part L2 of the Building Regulations, which came into effect in April 2002.
The revision called for all buildings with a floor area greater than 1000 m2 to be pressure tested to prove that the building's fabric is airtight.
To comply with the Building Regulations air leakage must be less than 10 m3/hour for every square metre of facade area.
Ed Westgate, managing director of building sealing and testing company HRS Services, said: "We reckon there is currently 80-90% deliberate evasion of pressure testing."