MNN

Thank you adsibob and markocosic. Smoke is the issue as the compartment floor is to make a safe escape from the upper compartment. As I understand it, protection from smoke is critical as the first concern, to enable people to escape. Later when fire penetrates people should be out. Markocosic shows presumably a European solution which shows filling the compartment floor void where the flue passes through. This makes common sense to me. (It also gives the flue termination dimensions that UK Building Regs use). Our HETAS installer claims filling the floor with insulation is against their code. Armed with the Sauresta info I'll contact Building Control. Many thanks markocosic

There has been confusion between HETAS requirements and AD B and J for years. We've struggled with woodburner flues and regulations several times. We've got much the same problem as ADSIBOB. The house is four storey. Twin wall flue from first floor level has to pass through a 30min fire resistant floor on the next floor. HETAS installer has put in the usual vented firestop at the floor. My concern is that the 'vented fire stop' will allow smoke (from an accidental fire in the room with the woodburner) through and smoke is the critical thing here from the means of escape aspect. I'm after some suggestions as to possible solutions before going toback to building control. For instance:- If the opening in the floor has an intumescent band around it at the floor level, is that likely to expand and stop smoke or is it likely that the temperature will not be hot enough to activate it before smoke becomes an issue?. Is that likely to be accepted as a solution. Using 1.46 would mean constructing a fire resistant enclosure up the next two floors which rather negates the reason for having a visible flue.