Hi, I've been racking my brains

and I think I may need to clarify some things as I may have conflated some points. The most likely scenario for the use of these suits would have been a chemical attack and that is why they are impregnated with charcoal, to absorb the chemicals(and aerosol dispersed bio weapons). Therefore the heavier the contamination, the more it has to absorb, the shorter the protective time. That's also why you use the fullers earth pads to mop up the chems on non-absorbent surfaces(boots, gloves, gasperator and weapon). In a nuclear/dirty bomb scenario, the problem is radioactive particles(I.E. dust), which the suit does not absorb, it only acts as a barrier to stop the dust getting on you and your clothes. The only things that will stop the radiation affecting you is a solid barrier(thick walls) and/or distance between you and the radioactive source. That is why you must get out of the contaminated area ASAP, or get deep inside a clean building, and dispose of the suit(as described) as soon as you step out of the contaminated zone. In either of the scenario's, the heavier the contamination, the shorter the lifespan of the respirator cannisters as they will clog up quicker. I hope this clarify's things a bit more
they laugh at us because we're different, we laugh at them because they're all the same