W/H TPRV discharge pipe termination

[pbennett1]

The above pipe terminates into a 2inch abs pipe which penetrates the garage firewall, and then terminates on to the garage floor. See attached photo(wall is on the left and refrigerator on right)
Shouldn't the abs pipe terminate to daylight on the exterior?
Plus, doesn't the pipe violate the firewall integrity?
Thanks,
Peter

[Jerry Peck - Codeman]

Hi Peter,

First, by the title, the water heater T&P relief valve is somehow connected to the 2 inch ABS pipe you are referring to, right?

And the water heater is on the other side of the garage / house wall, right?

There are two thing to remember:
1) The water heater T&P relief valve discharge is required to terminate within the same room or space as the T&P relief valve and shall terminate through an air gap.
- - Is there an air gap on the other side of the wall where the 3/4 inch T&P relief valve discharge terminates, and, does the relief valve discharge line even "terminate" on the other side of the wall?
2) The garage / house wall is not a "firewall", it is a "separation" wall which does not even need to have Type X gypsum board on it.
- - However, all penetrations through that wall are required to be sealed around to prevent the free passage of flame between the penetration and the wall from one side to the interior of the wall and to the other side of the wall. Which brings us to the two types of penetrations: a) "through penetration" of which that pipe would be an example, the pipe "penetrates through the wall", i.e., it goes in one surface and out another surface, which could be the top, bottom, or the other side of the wall; b) "membrane penetrations" and a good example of a membrane penetration would be an electrical box which penetrates one surface of the wall only. BOTH types of penetrations are required to be sealed around.

There may be some areas, possibly such as California, which require that wall to actually be a "firewall", i.e., a "fire-resistant rated" wall assembly which is required to be constructed precisely as the UL fire-resistance rated design shows it to be. I am not even sure that California requires a "fire-resistance rated wall" at that location, but have heard mumblings that it may be so.

If you need the IRC code sections I can post them for you.