No need for critical barriers
Historically it has always been necessary to erect critical barriers when decontaminating property and for a very good reason, "If you didn't you would re-contaminate the are you just cleaned with secondary contamination" Basically areas were isolated with plastic sheeting and negative and or positive pressures applied to keep contaminates entering the work area.
With chemical decontamination its usually faster easier and more cost effective to decontaminate the whole property.
When you consider the cost of isolation and NPUs and the time and expertise it takes you can imagine the savings here in terms of cost and time.
Generally speaking you can decontaminate a 3 bedroom property in the time it takes other contractors to unload the van and position the critical barrier paraphernalia.
Yes there are times when a critical barrier may be required but they are far and few between