Will dog urine cause damage to aluminum drain covers? The drain covers
are breaking.   This is a newly installed deck(less than a year old)
and we, the contractor and the other owners, cannot replace these
covers every year because of dog urine.  We need information so we can
stop this owner from allowing her dogs to use her deck as a dog run.

Hello sooze,

I found two mentions specifically about dog urine.  The first is a
kennel manufacturer that uses an aluminum alloy to reduce corrosion by
dog urine:

http://petkeep.com/online_brochure.html

The second is a central heat/AC unit manufacturer who says aluminum
coils are a poor choice vs copper because aluminum will be destroyed
by dog urine. See specifically the section on "disadvantages of
aluminum coil."

http://www.energyserv.com/html/condensing_coil__copper_vs._al.html

An aircraft site, discussing the damage done to an aluminum aircraft
wing states, "we discovered the remains of a raccoon or possum that
lived (and died) in the wing of an inactive twin beech requiring the
replacement of several wing ribs and skins in the area it used as a
restroom. Animal urine is very corrosive."

http://www.barronaviation.com/corrosion.htm

Nasa's website states that aluminum corrodes more quickly in acid or
basic environments.

http://corrosion.ksc.nasa.gov/html/electrochem_nature.htm

And as all of us who cook and bake with aluminum pans know, "High acid
foods, such as those using tomato products, can be in our pans, but
should be transfered to another dish for storage. Recipes that call
for a lot of high-acid sauces that will be in direct contact with the
pan should probably not be baked in aluminum. The acid in the sauce
might cause the pan to corrode."

http://www.metro-bakeware.com/using-doughmakers-bakeware/using-doughmakers-bakeware.html

HOWEVER, I found information that DOG URINE IS NOT very acidic.  The
brown patches on lawns that we all consider proof are not due to
acidity but rather the urea and excess nitrogen. The University of
Minnesota debunks this common myth about dog urine being acidic,
"Burned patches in lawns have been attributed to two properties of
urine: pH and nitrogen. Turf grasses prefer a slightly acidic pH, but
tolerate a fairly broad range of pH (5.5 - 7.5). Dog urine has a
normal pH range of 6.0 - 8.0 depending on the dog's diet and health
status. Urine pH values are not extreme enough to cause burning."

http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Nov0199.html

So with that I'll pass the baton and see if someone can come up with a
site discussing the chemistry behind the corrosion.  I felt that the
first two sites I listed didn't offer sufficient proof, so am posting
this only as a comment

Regards,

historybuff

Instead of using an aluminum cover, wouldn't it possible to use a plastic one?