What type of pipework must be used for the condensate drain on the I 24?

All pipework and fittings in the condensate drainage system MUST be made of plastic — no other materials may be used. Internal plastic pipework must be a minimum of 19mm internal diameter (typically 22mm OD), and external plastic pipe must be a minimum of 30mm internal diameter (typically 32mm OD) before it passes through the sleeved wall. All horizontal pipe runs must fall a minimum of 45mm per metre away from the boiler. (Page 11)