How to check breaking load of this chain
In the real world, chain failure is strongly depending on its environment. Presence of Water, dirty, abrasive substance, temperature, acid o basic surrounding, etc.
Maintenance items like lack of lubrication, inadequate tensioning, etc.
Of course, is depending on load, continuous load, intermittent load, impact load and so on
Generally, failure modes are for example tensile overload, impact, fracture, fretting, misalignment, overheating, roller seizure, galling
sprocket tooth wear, rivet failure and so on
Usually, these factors are present, not alone but in concomitance.
Attached you can find a brochure of Renolds chains, are a complete series of pictures of how a chain fail, this is very important, why you can see how chain fails and then take actions.
You can see a test machine for chains in
Anyway, I will make a simulation on tension of your chain