Soft Panniers near exhaust...

So I'm after some soft panniers to boost up cargo load, but on looking at the dri-riders sports panniers they dont look to have any heat sheilding on the bottom. They sit snug, just concerned about heat from the exhaust.
My question really is, how much heat can the material used actually take? (as it is sitting about 2centremeters from the exhaust hole).
.. and is there anything that could be used as a heat sheild? (ieL: if stitched on?)
My question really is, how much heat can the material used actually take? (as it is sitting about 2centremeters from the exhaust hole).
.. and is there anything that could be used as a heat sheild? (ieL: if stitched on?)