What do you think caused THIS...

Mark Eatherton

Goes to show you, just when you think you've seen everything, you haven't...

Thanks Dan Foley.

How much does a Watts Vacuum breaker cost?

Bob Bona_4

Whoa! Bahboom

JStar

Is that Lou Ferrigno's house?

Fred

Did they have a water main break somewhere in the area? I had a water tank (recently replaced) that had a vacuum Breaker on the cold water line, just before the tank to keep the tank from being sucked inward like that from any vacuum created by a broken water main. I replaced the tank but kept the vacuum breaker in the water line.

Zman

I am pretty sure the dueling booster pumps to the right are the guilty parties.
Is there a story to go with this one?

4Johnpipe

That's the new fangled inflatable exp tank. You get it into the tight space then add air to inflate...LOL

bob_46

Oh boy that **** mark .

Gordy

Holy food saver Batman!

Mark Eatherton

Zman said:

I am pretty sure the dueling booster pumps to the right are the guilty parties.
Is there a story to go with this one?

There is a back story, but Dan is writing an article on it, so you will have to tune in next month to see what the causes are.

I once saw a mash tun (large steam powered soup kettle converted to use in a beer making operation) that was sucked flat because an employee closed two isolation valves to the tun while under full steam, and then left for lunch.

Oddly enough, I'd warned the brewery owner to install a vacuum relief valve on the tank side of the iso valves to avoid this very same situation. He had a mechanical engineering degree and told me I didn't know what I was talking about and that his design was just fine, and I was trying to jack up his bill for nothing.

Okey doke chief. You da boss :-)

And then there's the demo lab at NAIT College up in Alberta Canada, where they take 55 gallon drums, fill them with steam, then close all valves and watch it collapse in on itself. Sets an indelible impression on the minds of young first year piping apprentii about the power of steam.

But I've NEVER seen a residential tank do this...

A while back there was a discussion about flashing 140 degree F water into steam by introducing a vacuum to draw the boiling point down. With water weighing in at .434 pounds per vertical feet, it wouldn't take much altitude to create the negative pressure necessary to cause 140 degree F water to flash into steam.

Vacuum breakers ARE cheap at that point, and some AHJ's require them (wisely) on the installation of pressurized vessels. I will be recommending it to the UMC and the USEHC during the next round of improvements. This is the very reason there is a 1/8" hole drilled in the top of a stand alone tank style water heaters cold water dip stick.

Stay tuned, and keep guessing.

ME

hot_rod

That is the key to vac tube solar collectors, the fluid inside boils around d 120F or lower, depending on how accurately they pull the vacuum. Or if there is a vacuum at all

Henry

This is what happens when one drains the fill line to a day tank on top of 34 floors

Mark Eatherton

Hatterasguy said:

Mark Eatherton said:

A while back there was a discussion about flashing 140 degree F water into steam by introducing a vacuum to draw the boiling point down. With water weighing in at .434 pounds per vertical feet, it wouldn't take much altitude to create the negative pressure necessary to cause 140 degree F water to flash into steam.

No, it doesn't take much altitude. Only 37,000 feet. 2.9 psi absolute at 140°F.

One of these days you'll take a look at a saturated steam table.

You mean like this one? http://www.engineeringtoolbox.com/saturated-steam-properties-d_273.html

I never claimed to be an expert on steam, but have always been taught that it is a great potential in hot water under negative pressures. That chart shows a need of -26 PSIG to flash 132 F water to vapor, correct?

Unless I am not reading this chart correctly, and their conversion chart is way off...

ME

Zman

"One of these days you'll take a look at a saturated steam table."

@Hatterasguy , you sure like taking little potshots. This isn't the first directed at Mark.

Are you guys old buddies that like to rib each other or are you just not " being nice"

ChrisJ

And here I thought if you tried to pull water up a pipe further than 29 feet or so you'd cause the top surface to boil.

Could be wrong, but that's what I'm remembering.


Unless I did something wrong I got 60 feet to get water to boil @ 140F.

ChrisJ

Ah I did make a mistake.
I took the absolute pressure and added it to the vacuum.

I came up with approx 12 PSI drop needed so I guess that means 27 feet so I was close until I added 14.7 to it.

Where did 23,000 feet come from?

ChrisJ

Hatterasguy said:

It was 37,000 feet. That's the altitude where the absolute air pressure is 2.9 psi.

You can obtain similar pressures with a column of water as you noted.

How is that useful to anyone?
We were talking about using water essentially as a vacuum pump not building a really high tree house.

vibert_c

Hatterasguy:
Thanks for the explanation, I greatly appreciate it.
Vibert_C

Lance

Tanks are designed to hold pressure in & not out. Burst pressure for a water heater is above 300PSI. Only a vacuum chamber or bathysphere designed for such can keep this from happening. However nature abhors a vacuum and will try and fill it. I had a mechanic start pumping down a hydronic system and before he could open a valve to let air in the steel tank imploded. It is why we open system to air first than start the pump. Water acts like a solid unless it reaches boiling point with reduced pressure. That would require it to be below say (800 microns - varies with pressure.) when it can vaporize and fill the space. But before that can happen the force of air pressure pushes on the tank as the liquid water leaves it. More than likely the tank is full and has no air in it. But as long as the pump is pumping liquid it will quickly achieve the necessary pressure differential to collapse these large tanks which have a large surface area exposed to atmosphere. Once it begins the tiniest kink, the integrity of the tank shape is compromised and very little pressure is needed to finish the job. Sounds like Whump, as my money left my pocket. Saw it happen to a train tank car you can see it here.
https://www.youtube.com/watch?v=Zz95_VvTxZM

ChrisJ

Hatterasguy said:

ChrisJ said:

How is that useful to anyone?
We were talking about using water essentially as a vacuum pump not building a really high tree house.

The original discussion began on another thread where a drop in pressure in the tank could cause the hot water in the tank to flash to steam. I noted that this is essentially impossible as the saturated steam pressure is exceptionally low at 140°F and that it could not occur under any typical circumstances.

This thread concerns the collapse of the tank strictly by utilizing a column of water to create the vacuum necessary to collapse the tank.

The required column is surprisingly small. I'd guess that 10 feet would do it. Seal the tank, open a drain that is 10 feet below the tank.............watch the tank implode.

What would stop air from entering the bottom of the column though?

Mark Eatherton

It will take you to what I call the GLUG GLUG GLUG syndrome.

Think of draining a conventional non diaphragmatic expansion tank that does not have a provision for releiving the vacuum. It takes F O R E V E R to drain the tank. Pressure in tank when drain drops to sub atmospheric, sucks air into the same hose water is draining from (GLUG) then lets more water out until equalibrium is reached, rinse and repeat.

This is where I put a small ice maker tap saddle valve on the pipe connecting the tank to the system, and introduce air into the tank to alleviate negative pressures and watch it drain the tank in 5 to 10 minutes. The ONLY time I will use a tap saddle valve on ANYTHING (pieces of crap).

On B&G's airtrol fitting, pulling the handle screw off allows air to go up the tube and releive the vacuum as well.

ME

ChrisJ

Mark Eatherton said:

It will take you to what I call the GLUG GLUG GLUG syndrome.

Think of draining a conventional non diaphragmatic expansion tank that does not have a provision for releiving the vacuum. It takes F O R E V E R to drain the tank. Pressure in tank when drain drops to sub atmospheric, sucks air into the same hose water is draining from (GLUG) then lets more water out until equalibrium is reached, rinse and repeat.

This is where I put a small ice maker tap saddle valve on the pipe connecting the tank to the system, and introduce air into the tank to alleviate negative pressures and watch it drain the tank in 5 to 10 minutes. The ONLY time I will use a tap saddle valve on ANYTHING (pieces of crap).

On B&G's airtrol fitting, pulling the handle screw off allows air to go up the tube and releive the vacuum as well.

ME

Curious how you plumb an ice maker in? I hate those valves too.
I'd assume if you're doing a 3/4" pipe you'd use a 3/4x3/4x1/4 tee into a 1/4" ball valve with a 1/4" to 1/8" adapter and some sort of compression fitting adapter?

SWEI

http://www.siouxchief.com/products/supply/access/ice-maker-boxes

RobG

ChrisJ said:

Mark Eatherton said:

It will take you to what I call the GLUG GLUG GLUG syndrome.

Think of draining a conventional non diaphragmatic expansion tank that does not have a provision for releiving the vacuum. It takes F O R E V E R to drain the tank. Pressure in tank when drain drops to sub atmospheric, sucks air into the same hose water is draining from (GLUG) then lets more water out until equalibrium is reached, rinse and repeat.

This is where I put a small ice maker tap saddle valve on the pipe connecting the tank to the system, and introduce air into the tank to alleviate negative pressures and watch it drain the tank in 5 to 10 minutes. The ONLY time I will use a tap saddle valve on ANYTHING (pieces of crap).

On B&G's airtrol fitting, pulling the handle screw off allows air to go up the tube and releive the vacuum as well.

ME

Curious how you plumb an ice maker in? I hate those valves too.
I'd assume if you're doing a 3/4" pipe you'd use a 3/4x3/4x1/4 tee into a 1/4" ball valve with a 1/4" to 1/8" adapter and some sort of compression fitting adapter?

Or if you don't have the space for a box, a 1/2" tee with a 1/2 x 1/4" compression fitting.

Mark Eatherton

Not piping an ice maker in, just using the self piercing tap saddle valve to allow air into the tank as water is exiting though a separate drain cock.

ChrisJ

Mark Eatherton said:

Not piping an ice maker in, just using the self piercing tap saddle valve to allow air into the tank as water is exiting though a separate drain cock.

Oh, I know Mark.
I was just wondering what the proper ways to actually pipe an ice maker were, that's all.

My fridge doesn't have an ice maker, but I know people that do and always hated those valves.

RobG

Mark Eatherton said:

Not piping an ice maker in, just using the self piercing tap saddle valve to allow air into the tank as water is exiting though a separate drain cock.

Understood, KC was just asking the best way to pipe an icemaker. You were talking vacuum relief.

Got a little off topic.

hot_rod

ChrisJ said:

Mark Eatherton said:

Not piping an ice maker in, just using the self piercing tap saddle valve to allow air into the tank as water is exiting though a separate drain cock.

Oh, I know Mark.
I was just wondering what the proper ways to actually pipe an ice maker were, that's all.

My fridge doesn't have an ice maker, but I know people that do and always hated those valves.

Buy a dual stop valve for under your sink. The 3/8 side feeds the sink, the 1/4 feeds the ice maker. I used the Dual Bob-Stop brands. Available as straight or angle pattern. Both the sink and ice maker get their own shutoff.

Much cleaner than a saddle valve, they should be outlawed

Zman

Outlawed for sure. While we are at let's take care of slotted screws and 1 7/8" trailer balls...

Bob Bona_4

Add ball valve circ flanges with slotted head actuation. Criminal!

bob_46

Deflategate ......Maybe there was a New England Patriot in the vicinity .

Mark Eatherton

The answer is still not known, but I think Dan Foley is on the right track here...and I agree with is assertions.

Vacuum ****

http://www.phcnews.com/content/vacuum-****-when-vacuum-not-your-friend

ME

Zman

Hatterasguy,
Think bigger. Let's say the tank is 100 vertical feet (hilly area) above a drain or water main break. In that case you would have around 45 PSI on the exterior of the tank.
Municipal water systems do have some vacuum breaks to protect from this. I don't know what the design standard is.
I have a friend that would know. I am curious and will ask him.
Carl

Mark Eatherton

What Carl said. Hat must live in a very flat location with extremely shallow mains, probably served by above ground elevated reservoirs.

Here in Denver, I can show you numeorus places that are exactly what Carl called out. in fact I just checked one area and found a 100 foot difference in ground elevation in 1200 horizontal feet of run. My wife use to work for the largest undergorund water utility west of the mississippi (Denver Water Board) and their "system" varies in elevation between 9,000' ASL and 4,500' ASL. Yes, they have vacuum breakers on their mains, but in certain isolated situations and conditions, they don't come into play. Vacuum breakers are a minimum code requirement from IAPMO, but that code doesn't cover 100% of the USA.

Vacuums happen and if not prepared, this is the results.

ME