Dish soap is not designed for this type of application. It will definitely affect packings and other components. I would argue the cost of proper foam. It is a cheap loss control tool and when presented to insurance companies in that manner, you will be surprised at the view. IT stops loss far sooner and therefore payouts for insurance in several types of fire damage. It also reduces loss from water damage since far less water will be required. There have been arguments that it will mask arson evidence, but that is not entirely true.
for structural uses i agree with you for wildland purposes the dish soap does a good job instead of foam use
We carry 60 litres 'A' class delivered through the hosereels and 240 litres 'B' class foam delivered through deliveries 1 and 5.
Foam on a residential structure fire never, the stuff is nasty and some poor Jo Public has to go back to live in there. We use 'A' class foam at bushfires but only if it is environmentally sound to do so, we don't want to be killing the lesser spotted tree bat.
'B' class is used on fuel fires and large scrap metal fires however before you start squirting it about you must have enough to finish the job normally 240 litres isn't enough. We do have strategically bulkie bins around the metro area but you would be looking at a private company to deliver more.
We train lots with pretend foam way more than I actually use it at jobs. It is an interesting thought of using foam at a residential structure fire.