Fire resistance rating of blockwork with perpend joints

[Minky]

Hi,

 

Does anyone know if having perpend joints along a blockwork wall, removes or reduces the fire resistance rating that blockwork would provide in general?

 

From what I understand brick and block have quite a good fire resistance rating but just wondering if that counts for nothing if perpend joints are in a wall providing ventilation to a cavity?

 

Would having cavity barriers make any difference to this?

 

Can't seem to find any guidance around this online.

 

Cheers

[Mr Punter]

Unless this is 4 storey plus, brick / cavity / block construction gives adequate fire resistance.  The cavity is not strongly ventilated enough for the chimney effect.

 

The weepholes may allow an external fire into the cavity, but the building would likely be compromised by then in any case.

[Minky]

Many thanks for this.