Entrapment in cooling pond disharge
Entrapment in cooling pond disharge
(OP)
We have an unprotected dishcarge point from our power plant's cooling pond. It is possible that swimmers can come near it and we need to decide how to protect against someone becoming trapped in the flow of water. We are considering either a cage around the discharge or just floating barriers with warning signs. At it's smallest point the pipe (which starts at the bottom of the pond, about 5 ft below the surface) is 70" diameter and the flow rate is about 1 m3/s. Therefore, the average flow speed is 1.3 ft/s. How fast of water flow would be enough to trap a person?





RE: Entrapment in cooling pond disharge
RE: Entrapment in cooling pond disharge
RE: Entrapment in cooling pond disharge
1. Put up a fence around the pond with "no swimming" signs.
2. String a safety rope upstream of the inlet (such that if someone falls in by accident, they have a last chance to grab onto something and pull themselves to safety.
A local irrigation channel is about 12 ft. deep, with water flowing up to 10 mi/hr (guesstimating here). The channel enters several siphon tubes along its ~30 mile run, enabling the flow to traverse deep valleys. The only thing preventing somebody from drowning in a siphon are the items listed above. I think some of the siphon inlets located near a state park also have an alarm switch rigged to the safety rope, to let somebody know when something big has snagged the rope.
Floating, moored buoys with a rope attached could work too, perhaps even with danger/warning signs painted/affixed on the part of the buoy above water.
A safety cage can work, but how do you keep a submerged swimmer from getting "pinned" on it (I'd argue that it's not my problem if 1 and 2 are there too, it's the swimmers own damn fault). Also, it will act as a strainer, and need to be periodically cleaned of leaves/branches/beer cans etc. etc.
RE: Entrapment in cooling pond disharge
tom
Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessor.com
RE: Entrapment in cooling pond disharge
I can see the warning labels on fences now:
"WARNING - Don't fall in!"
"Caution: Water can cause drowning"
Seriously, Tom is right. Start with your corporate attorney.
RE: Entrapment in cooling pond disharge
> Sorry for the confusion - is a person were to get caught in the flow it could carry them into a 70" diameter pipe that is at least 50 ft long. They could then bump their head and/or become trapped part-way through the pipe.
Are you insane!!!!!????
Let me re-phrase that: "If the person were to get caught in the tube THEY WOULD DIE."
Also, have you decided yet whether it is sucking water in or blowing it out yet? Kind of important to know this.
RE: Entrapment in cooling pond disharge
Yes, I realize that a person would die - I just did not think I had to actually say it.
The water would suck someone into the pipe. What I am looking for is whether or not the flow is enough to suck someone in. A lawyer or insurance agent will not be able to tell me that. I would like to have some idea how much of a danger it really is before we go and do something drastic. Once we install some kind of a guard we are stuck with it - if the danger is high enough to install a guard then we will have to maintain and inspect it, etc.
RE: Entrapment in cooling pond disharge
RE: Entrapment in cooling pond disharge
Make it difficult to impossible for a person to get into the pond in the first place, with plenty of warning signs, add a simple two-layer guard system (floating rope with a signal, outer fixed barrier/cage. Then run it past the attorneys.
I'd also look into your local/state codes regarding irrigation ditches, siphons, etc. and see what the minimum for these hazards is.
RE: Entrapment in cooling pond disharge
An "Attrative Nuisance"; A legal term.
Geez! Andy! here in California you had better be talking the worst case scenario, cause there are people out here who would be willing to sacrifice their children or anyone else to make big bucks from deep pockets. You have to say those hard words or else no one will listen and then only then a few will. You'll have to say it more than once. If you cannot convence these corporate types then maybe you should leave. It's up to you of course. My advise is...
Do whatever you can to exclude anyone who is not authorized to be at that pond, from entering that pond.
This includes razor wire fence to a hard top cover, whatever.
Do not let it be on your watch that a small child, a teen or drunk adult get's sucked down the tube because someone did not think it possible. If you can think it's possible then it can happen. Do you want that?
I wish you well
pennpoint