2019 Tech Report Jan-Feb

“Another designmethod that may be incorporated has a fully open vent end point that is the “exterior stack extension” diffuser. The “exterior stack extension” diffuser has the relief termination piping extended on center up and into a separate larger-diameter stack extension. Any rain and snow that gets into the extended larger diameter stack draws to the internal surface and drops down and drains out drain hole(s) at the bottom. This keeps the rain and snow fromgetting into the relief termination piping that is on center internally.” These are available commercially or can be field fabricated. Designs are available by searching for “No loss stack discharge”. Lastly diffusers like these are available premade and field fabricated but, they are not recommended by IIAR-2-2014. They impose an unknown resistance on the piping system and calculating the effect on the relief piping is a guess. They also need to be engineered and documented to ensure they have adequate exhaust area.

In summary, as a designer we have many choices for the discharge from a relief system. We need to ensure it is designed, documented and installed per the design.

RETA TECHNICAL REPORT PAGE 6