It wasn’t too long ago that ASSE 1070 was touted as the standard which would solve all the problems with thermostatic mixing valves. Unlike an ASSE 1017 thermostatic mixing valve, ASSE 1070 valves would provide thermostatic mixing with failsafe (endpoint) protection.
In other words, if the valve failed to properly perform in setting the temperature, the water flow through the valve would close to a trickle. Thus, scalding would be prevented.