Technically, if you are providing a service or purchasing/paying out any type of item by weight you are supposed to be using a certified scale.

If you want to have a "certified" scale, You need to purchase a NTEP "legal for trade" scale. On top of that, depending on your state, they have to be inspected for weights and measures every 1-2 yrs. Here in VA, the authority over this is the Agriculture and Consumer Services. It may be different where you are.



It can get pricey for an NTEP scale. I just bought 2 for our office. a 300/.1 bench scale and a 5k/1 floor scale. I think most scales that I've seen used by yards in box trucks are hanging scales.

It would depend on what kind of weight requirements you need as well. My 300/.1 bench scale has a battery option and I can take it out and use it on the road in front of clients but I use this for E scrap. If i was weighing ferrous... 300 lbs would most likely not suffice.