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Latexman (Chemical) (OP)
18 May 06 8:06
Currently using an upside-down, open, plastic appropriately sized can or bucket on top of the vertical tailpipe (for better dispersion) that is connected to the roof or pipe with enough slack so it can come off, but doesn't become a long distance projectile.  A yellow "danger circle" is painted around the tailpipe to indicate the can or buckets reach.  Weekly or monthly walkabouts ensure they stay in place.

What do you use and is it better?

Good luck,
Latexman

Ashereng (Petroleum)
18 May 06 10:29
I have never seen anything approaching what you have just described. I know for a fact, at one employer anyway, if I suggested that, I'd be escorted out the plant.

I have seen secured either by bolts/nuts/screws or welded, with hinge and latch.

I don't think the site safety officer would let me get away with a circle that says "Danger, Flying Bucket Zone".

Imagine the 6 o'clock national news when someone gets injured, and they do a close up of the circle and bucket.

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

Ashereng (Petroleum)
18 May 06 10:29
Latexman,

You don't have to answer this, but I am curious.

What kind of plant is it, and where is it, that is allowing this?

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

StoneCold (Chemical)
18 May 06 10:37
Latexman
I have heard of people putting plastic pipe thread protection caps on the ends of the tailpipes.   We just bend ours over horizontal or even tipped down at a 45 for our tail pipes to avoid this problem.

I don't think I would get the Ok on the bucket scheme either, I work in the US, but it is a very crazy place, we would be more apt to let the vent fill with water than put the effort out to put a bucket on it.

Regards
StoneCold  
sshep (Chemical)
18 May 06 11:30
For rain a weep hole can be drilled in the elbow of the tailpipe where it turns into vertical. Haven't ever given much consideration to solid debris falling in. -sshep
JimCasey (Mechanical)
18 May 06 12:54
I remember calling on our favorite local nuclear power plant.  The Moisture-separator-reheators are on the roof of the turbine building.  There are 16" x 20" safety-relief valves on the MSRs, with output stacks tipped up 45 degrees aimed over the parking lot. The MSR sSRVs are set at about 225 psi, so when they open it will be theatrical.  Each stack is "protected" with a welded steel cap made of approx 3/16" plate-lashed to the valve with a lanyard of 1/4" aircraft cable.  I always imagined a car in the parking lot cut in half by a flying, 100-pound, trash can lid.  
sethoflagos (Chemical)
18 May 06 13:04
Latexman,

sshep beat me to the weephole!

The 'Chinese Hat' used to be a popular device for this. Basically a shallow sheet steel cone secured some distance from the end of the tailpipe by welded strapping.


  
Latexman (Chemical) (OP)
18 May 06 13:20
There is at least one product on the market that is similar to what I discribed:

http://www.oseco.com/pages/products/PDF-new/Pipe%20Cover.pdf

This would be safer than using a plastic container, but we have to go through a Safe Work Permit procedure to access the roof anyway.  So awareness is heightened when inspecting these.

We've found bee hives, dirt dauber hives, and bird nests in our relief tailpipes.

Using PHAST shows a LOT of difference in the dispersion of emissions depending on orientation of the exhaust.  

I've also seen folks use shower caps, but they are not as  robust.

Good luck,
Latexman

Latexman (Chemical) (OP)
18 May 06 13:23
I've seen the "Chinese Hat" too, but wouldn't it divert flow horizontal and down?

Good luck,
Latexman

Latexman (Chemical) (OP)
18 May 06 13:31
Ashereng,

Do your hinges rust in a marine environment (U.S. Gulf Coast)?  I have concerns with that.

What is the latch for, to hold it open when it opens?

All this sounds too mechanical to be as trustworthy as a PSV or RD.

Good luck,
Latexman

Latexman (Chemical) (OP)
18 May 06 13:34
StoneCold,

Fill with water . . . and bust in the winter?  I'd rather cover the opening than heat trace all those tailpipes.

Good luck,
Latexman

Latexman (Chemical) (OP)
18 May 06 13:36
sshep,

We have a 10 mm weep hole in the tailpipe too, but we don't want to let weather and wildlife continuously insult it's intent or there could be problems when it's needed.

Good luck,
Latexman

Ashereng (Petroleum)
18 May 06 13:48
Latexman,

No, it's not a PSV or anything. It's a "shield" or "roof" for the tail pipe to keep water out, debri from falling in, etc.

The hinge and latch is to hold it down in place. The latch and hinge allows you to "open" the roof to get at the tail pipe in case anything fell into it, and you want to get it out.

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

Latexman (Chemical) (OP)
18 May 06 13:51
Ashereng,

Does it divert the flow away from a vertical path?  Sounds like it would.

Good luck,
Latexman

Ashereng (Petroleum)
18 May 06 13:54
No, I don't think so. It is usually a fair bit up, so by that time, everything is already dispersed.

We are using it in very low pressure vents, well under 20 psi.

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

Latexman (Chemical) (OP)
18 May 06 14:19
Ashereng,

I don't know.  We have some high pressure reactors with pretty big relief lines.  It would take quite a bit of structure to make it strong enough to take the thrust and impact of the flow.  If it is strong enough of a roof or shield to do that, I don't see why it would not divert the flow.  Id would definitely be too heavy for a person to unlatch it and move it out of the way.

I'm talking a 12" tailpipe at sonic velocity with two phase flow.  The impact, as Emeril says, would go "BAM"!

Good luck,
Latexman

Ashereng (Petroleum)
18 May 06 15:36
Latexman,

We are on the opposite sides of the spectrum.

I have a field compressor station with 4" to 6" relief vents at low pressure (under 20 psi) going out under the eaves of the enclosure. Most of the time, I don't expect anything going out, but am trying to keep things from coming in.

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

Ashereng (Petroleum)
18 May 06 15:40
Hey, Latexman, wait a second. You have a 12" pipe at sonic velocity, and they let you use a plastic bucket?

The oseco pipe cover would be a definite improvement I would think.

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

Latexman (Chemical) (OP)
18 May 06 15:49
Yes, I like the looks of the pipe covers too.  

Good luck,
Latexman

JimCasey (Mechanical)
19 May 06 14:30
I just can't help but to imagine the combination of a 12" sonic pipe, Plastic buckets, a coupla' kegs of beer, a large open field.... Sounds like a fun family event.  Scoring for range, accuracy, hang time, maybe style points for costumes (Best pocket protector?) .  Not unlike the pumpkin cannons you see in the news.

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