Fire collars and intumescent wraps

[Guest Jason grey]

Good Afternoon,

 

A small 3 storey block of flats (housing 6 flats , built 1960) has  two internal cast Iron rain water pipe that pass from the flat roof deck down into the communal area and continues down through 2 solid concrete floors in the communal staircase area to the external ground floor. The single staircase /communal area where the internal rain water pipe passes through is not compartmentalised by any fire doors so in theory any fire in the communal area could travel up the stairs anyway so the pipe posses little risk? On the second floor  where the pipe passes from the ceiling into the roof there is a circa 50cm gap between the pipe and the (12.5mm plasterboard ) ceiling lining where the plasterboard seems to have been cut poorly .

 

Is it needed for the internal rainwater pipes to have a fire collar or pipe wraps installed , would this collar/wrap need to be fitted on the ceiling abutment and would it each floor require a collar/wrap?

 

Secondly does the gap between the pipe and the ceiling lining cause a risk and if so how could this be reasonably rectified? Replace current plasterboard section  and re cut new with better fitting aperture to fit pipe more tightly , seal with intumescent mastic?

 

Any guidance is greatly appreciated 

 

 

[AnthonyB]

It sounds like the vulnerability is where the pipes enter the roof void and this is the junction needing the most attention.