Std minimum 80/20 wool/poly twist – will be relatively hardwearing. The ‘oz’ rating is relevant and you will see a relationship between this and the wear rating for room suitability. Loop or berber might do, it’s often lower quality and wears less acceptably – some would say – and you would probably not find it in many hotels as an example.
If your budget allows look at an Axminster or Wilton from a brand; like the ‘standard’ Brintons range in 40 oz. Something like Bell twist will be rated for ‘extra heavy domestic’. The brands like Brinton’s are generally extra for the colours and consistency.
Brintons upper ranges are Kind of things you may find in the house of commons, hotel contracts etc. But all sorts do get used.
Polyxxx carpet is servicable, colourfast and steam cleanable, but not necessarily pleasant.
Do you really want a relatively costly carpet that lasts 15yrs though? Maybe a cheaper one and a plan to redecorate after 6yrs works better with young kids about – less to worry about (the expensive carpet I mean!)..