Fire Resistance of Dry Riser outlet boxes

[Stobswellpond]

Hi, I'm looking for a pointer where I can find information on the fire rating of  a dry riser outlet box. The face of the box is in a protected lobby, and the riser pipe is in a service riser with all other services. The service riser itself goes the full height of the building 20 storeys and has a metal grating floor at each floor level. Have been unable to put my hands on the fire strategy yet, however the riser doors between the risers and protected lobby appear to be FD30S.