There are a number of Class-B motorhomes that are being built on Van chassis. Some of these vehicles come with European "Commercial" tires. I had a discussion with one owner that wanted to find the Load & Inflation tables for these tires.
Well for US tires there are books published annually by the US Tire & Rim Association that have the tables used for almost all tires in the US. In Europe they have a similar organization the European Tire and Rim Technical Association. Both manuals have dimensions and load limits but the ETRTO manual does not have tables as they expect people to inflate to the tire sidewall pressure or the pressure specified by the car or truck company. BUT they do provide a formula. It is a bit involved but I worked up a spreadsheet that you can use if interested. You do need to know the Max Load for a tire and the inflation level required to support that load but you can then work out the results for your application.