Formwork Camber for Flat Slabs - Eng-Tips

Does anyone have a typical detail that lists the required formwork camber for flat slabs with drop panels (and perhaps also for flat plates)?
I am reviewing a typical detail sheet that we have for formwork camber for flat slabs with drops, giving cambers at critical locations such as mid-panel and mid-span of interior and exterior spans of flat slabs with drops, for 3 sets of spans, viz. 5.8 m to 7.6 m, >7.6 m to 9.0 m, and >9.0 m to 10.7 m. However I do not know how this was developed. Some of the cambers seem suspect because where I would expect a lesser deflection than another location, the specified camber is greater.
I would expect that the camber should equal to the immediate dead load deflection...but I am not sure. Perhaps the dead load deflection should be determined by running SAFE for a number of geometries/loadings.
Or is it the practice to to take a ratio (span/360±?) of the orthogonal spans and diagonal span to determine the cambers, and if so, what would that ratio be?
So to repeat my question, does anyone have a typical detail that lists the required formwork camber for flat slabs with drop panels (and perhaps also for flat plates)? And is there a span ratio should the camber be made equal to? If I was putting together a typical detail for camber, any camber would reference the floor plan where spot cambers would be shown. As noted above, the camber may be betied to the span, but so many other variables of the design would go into it that tieing it just to the span would be an oversimplification.

I would also be surprised to see camber at all for the lower end spans that you list, deflection with a reasonable slab thickness should not be a problem. We should be careful in how we approach our wording on all of this - I may camber my formwork to counter anticipated deflection in my formwork and call it formwork camber, but when we want the structure to have a certain initial camber, it must be clear that this is the intent. On a recent revision of ACI 301, there was quite a bit of discussion as to the context and use of the word camber in the document.

When the specifier requires a camber, that calls out an indicated profile of the final work, so the formwork should be made (and priced) to provide that profile. But calling to formwork camber could seem to some that the actual camber of individual members of the formwork or falsework would be per the direction of the speficier.

Yes, the initial camber is created by the proper setting of forms, no I wouldn't call it formwork camber. Has anyone established what the approximate percentage cost extra is to camber the forms vs. not cambering them for a flat slab with drop panels, say for a 9 m span? Any formwork contractors on this forum? Anyone who perhaps tendered a project both ways, or has obtained these costs for a project from a formwork contractor? If not I suppose I can ask a local formwork contractor.

<5% ?
5% ?
10% ?
>10%?
I'll see what we would rough out from our estimating department.

There are times when the geometry of the structure happily aligns with logical breaks in equipment dimensions and the costs would be negligible. And there are times when the whole world would need to be tweaked to accommodate a camber so small it could get lost in construction tolerances. So any feedback will come with quite a few grains of salt.

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