Industrial Floor Slab 3

[Zambo]

Can anyone advise on acceptable tolerances for the surface level of a ground floor concrete slab. The slab is not specified as a "super flat floor" it is for a heavy industrial factory floor. British Standard is my preferred standard but ASCE would also be fine. I am hoping someone can give an overall tolerance for the whole building and also a local tolerance, perhaps under a 3m straight edge.

 

[ironmon]

Typical Proceedure would be to specify an Ff/Fl number (invented by Alan Face

http://www.allenface.com/)

For a typical warehouse with random traffic use 35/25
The next step up would be "flat" at 45/35
very flat = 65/40
super flat = 100/50

 

[valleyboy]

I dont know if you have access to it, but the Concrete Society Suppliment to Technical report number 34 'Concrete Industrial Ground Floors - Specification and Control of surface regularity of free movement areas' is an excellent resource.

There are three different qualities of flooring dealt with. The best quality is FM1 (which the report suggests will only be obtained by specialist flooring contractors using specilaist techniques) to FM3 which is a lesser specification. The report suggests that FM3 will be suitable for wide aisle warehouses where reach trucks are used and where stacking height will not exceed 8m OR for manufacturing facilities.

Taken rom the report:-

Max vertical deviation over 0.6m width=2.5mm (quality FM1)
=3.5mm (quality FM2)
=5.0mm (quality FM3)

Difference in level of adjacent points on a 3m grid
=3.0mm (quality FM1)
=6.0mm (quality FM2)
=8.0mm (quality FM3)

I hope this helps.

VB

 

[Zambo]

Ironmon,

thanks for the info - I think 35/25 could be appropriate as it is a factory, there is no racking system and I do not see that the functionality is affected by some variance in the floor level. Is there a way to express 35/25 standard as a general +/- tolerance for the floor slab as a whole and a lesser variance under a 3.0m straight edge.

Valleyboy,

I have just made an order for a copy of the Technical Report you recommend - 115GBP - not cheap. Is there a further value for the overall difference in level across the entire floor slab, perhaps +/- 25mm for example.

 

[Bagman2524]

See ACI 302.1R Guide for Concrete Foor and Slab Construction. Section 8.15 of the 96 edition covers floor flatness and levelness. It references ACI-117 quite a bit.
FF is the flatness number. It controls local surface bumpiness by limiting the magnitude of successive 1 ft slope changes.
FL is the levelness number. It controls the local conformance to design grade over distances of 10 ft.
As previously mentioned:
35/25 is typical for thin set flooring or warehouse floor with moderate/heavy traffic.
45/35 is typical for warehouse with air pallet use, ice rinks, etc.
25/20 is for carpeted areas of commerical office buildings.
20/15 is typical for mechanical rooms, parking structures etc.

 

[Zambo]

Bagman,

any suggestion what my slab should be classed as. No racking or high reach forklifts. The factory is for heavy fabrication and welding works. The plant operating on the factory floor will be forklifts and delivery trucks.

We have used a dry shake floor hardener which has given a good appearance and I think durable floor, but the application of the 5mm thick hardener beofre power floating has had some effect on the final level.