The newest version of the Minnesota State Plumbing Code, published electronically on November 13, 2012, now requires a safety device to be installed on bath tub faucets to help reduce the potential for serious scalding injury. Here's the exact text, which comes from section 4715.1240 of the Minnesota State Plumbing Code:
Subp. 4. Hot water temperature control device for tubs. Bathtubs and whirlpool tubs must be provided with water temperature limiting devices set at a maximum water temperature of 120 degrees Fahrenheit to reduce the risk of scalding, according to ASSE Standard 1070.
This means that the water coming out of a bath tub faucet needs to be tempered so that the hottest water that can come out of the faucet is 120 degrees F. This was already a requirement for single handle faucets, but now it applies to two-handle faucets at bath tubs as well.
So how is this done? I asked Mark Jerde of RightMark Plumbing how he achieves compliance with this new requirement. He installs thermostatic mixing valves conforming to ASSE 1070 at the supply lines to bath tub faucets.
One such mixing valve is the Watts MMV series, pictured at right. Just don't look for these types of valves at big box home improvement stores; they don't sell them. Maybe this will change soon. For more info on this new standard, click here: ASSE 1070
Author: Reuben Saltzman, Structure Tech Home Inspections