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.

Thanks,
George

Just a thought.
Add a reducer (expander) to expand the end of pipe to 4", put screen
over that. Glue the pvc part on to pipe, or just add a sheet metal
screw or two. Use a coarse screen. That way you got more surface area.
I'm guessing you now have a 1.5 inch pvc pipe. I dont know anything
about radon piping.
1/4" hardware cloth will keep birds out, but not bugs. Better than
nothing I guess..... A 1/8" screen would be ideal, if they make such a
thing.

The expanded pipe should shed snow better too.