Floor Drain in recessed slab?

[John_187]

There is a room that has a recessed slab. The slab on grade is 1 foot lower than the rest of the building slab. However, the finished floor of this room is the same height as the rest of the building. This is a pedestal elevated floor, so that there is a void space of 1' between the floor and the slab. The void space is also guarded from ground water with water stops.

The question is: Is a drain required by any code in the slab of the void space? Just in case the fire sprinklers go off, water would seep/leak down into this "bathtub". There are cable trays in the void space. However, if the fire sprinklers go off, lots of electric equipment above the floor will be damaged anyway. And even if there was a drain down in the void space, water would damage the cables before it got to the drain.

I am not immediately seeing any code requirement for any drain on the void space slab. Please advise if you know more, thank you

 

[PEDARRIN2]

This is common for elevated pedestal type floors. There is no code requirement for this floor drain, but it sounds like whoever designed the plumbing system put it there for exactly the scenario you are thinking - sprinkler water in the room.

 

[MikeHalloran]

<totally irrelevant tangent>
I was once asked to comment on repurposing part of a former bank's data center to a laboratory for medical instrument development.
The proposed lab area had a raised pedestal floor in a pit about 24" deep. The remainder of the building also had raised pedestal floors and separate pits. This room had been a high security enclave, so it was walled off above and below the floor.

I suggested that there was a risk of liquids being spilled on the (removable panel) floor, said liquids being possibly contaminated with pathogens, so there was some risk of contaminating the entire subfloor/sump, so perhaps we should consider removing the floor and pedestals and putting the laboratory down in the pit, with stairways and ramps for access. It was a big room, so we would not have lost a lot of floor space to the stairs and ramps.

TPTB decided instead to fill in the sump with concrete.

There was a delay in construction because the subject large room was on the second floor, and we needed to reinforce the existing columns that held it up, and add some more big columns.

The office space on the first floor, below the former sump, was sort of usable, but was broken up by a large number of very fat concrete columns. When done, it felt like a nicely carpeted and slightly roomier version of a missile sub's 'Sherwood Forest'.

</totally ...>

Mike Halloran
Pembroke Pines, FL, USA

 

[dbill74]

Is a drain required by any code in the slab of the void space?

No. There is no code requirement. However, that does not mean you cannot put a FD below raised floor.

The thing you need to consider is what is the space above used for and what is the chance/risk of fluids entering the void below the floor. From your statement, it sounds like this is for a computer server room. In which case the only real source of water would be from CRAC unit condensate and the small amount of water those generate.

You mentioned a concern about sprinklers. You're right that any electrical located below the floor would be rendered scrap. In such an event the cleanup crew would bring in a portable submersible pump to remove the water. But how often is that going to happen? Hopefully, never.

 

[John_187]

Thanks you everyone for the help