rebar seat on insulation

huangyhg

rebar seat on insulation
i am designing an industrial 8" concrete slab with radiant heat.  the slab is poured directly on top of 2" rigin insulation.
my concern is that if standard rebar seats are used for the reinforcement, will these puncture the insulation whenever the rebar is stepped on?  
this would leave my rebar near the bottom of the slab and also possibly damage my pex tubing for the radiant heat.
does anyone know a good solution for this problem?
as a designer is it even my place to be concerned with this issue?
thanks
how about using chairs with sand plates or concrete dobies to spread the load out?
what taro states is what is used a lot in refrigeration warehouses where insulation is used beneath the slab.
i believe they are also called "sand chairs".  they have been widely used for slab-on-grade construction.  they are typically used to support rebars or even post-tensioning cables.
i am not selling this product but here is a link which you can see what do they look like.
review construction practices with contractor prior to beginning the concrete pour.
review with them what you expect in the way of a finished product.
(do not tell them how to do the work)
discuss with them how they intend to construct the slab.
(i would expect discussion of the use of power screed, curing procedure, finishing procedure, etc.)
do all you can to insure that you get the finished product that you want.
(space rebar out as much as possible, locate joints reasonably, etc.)
if the rebar weight is too great, then you can use masonite or osb over the insulation.  often used in these environs over void form...
dik