Do you know whose beams and blocks they are - as in the make ?

The makers must be in the habit of backing up the claims in their catalogues for example.

For example Cemex claim

"

What is the fire rating of the beams?

The 155mm beam is rated as 30mins and the 225mm beam has 60mins fire rating. If required the fire rating of the overall floor can be increased for upper floors with the addition of a fire rated ceiling below the floor."

https://www.cemex.co.uk/floor-systems-frequently-asked-questions

Presumably they have test results to show that ?

Apologies if this is stating the obvious.

Mike

The problem nowadays is that construction needs to be tested as a composite arrangement. Confirming that the beams are 60min does not imply that the beams and associated infill are 60min even though common sense might suggest same, more espec with a 75mm sand and cement finished floor over. This building is +25 years old pre-dating the focus on fire certification of just about everything structural. I had the same problem in an old office building that we were converting to a hotel recently. I brought a fire engineer in to advise on the fire resistance of the wooden floors. Even with computer simulation using way above average room fire load, suggesting compliance, we were unable to convince BC of the 60min REI rating without  test documentation. We did consider mocking up a section for testing but the £50K test house fee put that off! 
Like never before, fire safety is front and centre of all projects, evident also in BS7671 and the installation of electrical services. As an aside, the qualifications attendant to electrical installation practice, such as the 2391, seem rather stuck in indirect shock protection, rarely pitching questions on fire safety.

By the way, a rather good point Olympus Mons, yes, I have seen the dirt and grime that builds up on exposed wiring systems. I think I will book my table well away from such systems in future!

Morning Lyle

I am not sure about NI but here in England your question would be one for the Fire Engineer. Us electrical bods cannot put finger to keyboard until we know what the Fire Strategy is for the building.

JP

The issue here isn't the integrity of the beams (that is certified) its the integrity of the floor structure in its entirety, to the passage of smoke. The manufacturers can't guarantee there won't be tiny gaps between them when installed. I appreciate you say there is a 75mm concrete screed above, however, playing devil's advocate, how can you be sure there isn't a large crack in it, this being an older building?
My suggestion would be to ask a specialist fire stopping company to check, seal any defects and certify it. BC would certainly accept it then. A quick google search will give you the names of suitable candidates. 

The issue here isn't the integrity of the beams (that is certified) its the integrity of the floor structure in its entirety, to the passage of smoke. The manufacturers can't guarantee there won't be tiny gaps between them when installed. I appreciate you say there is a 75mm concrete screed above, however, playing devil's advocate, how can you be sure there isn't a large crack in it, this being an older building?
My suggestion would be to ask a specialist fire stopping company to check, seal any defects and certify it. BC would certainly accept it then. A quick google search will give you the names of suitable candidates.