On Mon, 28 Jan 2013 06:58:04 -0500, George wrote:

Our radon outlet pipe ends in a down-facing elbow, above the 2nd story
roof. When I installed it, I put a screen over the outlet, thinking to
prevent bugs and birds from nesting. In recent bad weather, the screen
got plugged with snow, stopping the discharge. I pulled the screen off.
Now, I'm wondering whether a screen is necessary. The airflow is fairly
strong, and cool in the summer, which I think would discourage bugs.
Birds, ... who knows?

If anyone has experience in these matters, I'd appreciate hearing.

Aggregated reply:

- The screen was window screen, so quite fine pitch. And, the pipe is
3".

- After more thought, it might not have been snow plugging it. It's
been cold (for here), down to 0F at night. It might be that the moist
air from the sump just froze on the screen.

- IMO, it's impossible that anything could get into the basement. But,
if a (stupid) bird got over the elbow, and then fell down the riser to
the fan, ... yuck.

- I could put coarser screen over it, to keep birds out. But, I'm
concerned that might just make it more appealing to (say) yellow
jackets. double yuck.

Alas,
George