beecrofter wrote:

On Jul 5, 4:15 pm, Jeff Wisnia wrote:

Norminn wrote:

I just read an article about a horrible injury to a little girl in
Minnesota. This happened in a wading pool and it is difficult to read
about. Here is a link to the story:
http://wcco.com/topstories/local_story_185085504.html

It is summer and pool time, so take care of the little ones.

Someone's head(s) should roll over that kind of sloppy oversight and
maintenance.

But, I was puzzled by this line from the story:

********

In most public pools the drain cover is screwed in and cannot be pulled
off. According to the Consumer Product Safety Commission, the pressure
on some pool drains can be as strong as 300 pounds per square inch.

********

I don't see how a pool drain could suck with a force of more than one
atmosphere (14.7 psi) plus about another 1/2 psi for every foot of pool
water depth above the drain.

I think they must have meant a "total force" of 300 pounds sucking
something down against a drain opening of about 20 square inches or so.

Jeff (Hoping he hasn't forgotten his high school physics.)

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.


wanna bet 300lb/sq ft


I'll bet WITH you on that one...

That's why some poor souls have gotten "stuck" onto a pool drain and
couldn't generate enough push or lift to get themselfes freed before
they drowned.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.