What is Water Hammer?
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- Опубликовано: 18 май 2024
- Hydraulic transients (also known as water hammer) can seem innocuous in a residential setting, but these spikes in pressure can cause major damage to large pipelines and industrial pipe networks. In this video, we briefly discuss how water hammer occurs and how engineers mitigate the effect.
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If you shut a fire hydrant really fast you may have a lady come running out of her house yelling that her water heater just started leaking a lot. Don't ask how I know that.
william Greene 😂 lol
william Greene REPORTED
I thought that water pipe for fire hydrant do NOT connected to conventional water pipe for supply the houses
@@conradkenneth5216 reported?
Lol
Talking about the “water hammer” effect is extremely important, and none of the less extremely interesting. I’m currently a pipefitter, and I was on a job that will not be named. I was working for a contractor at the time that had work inside of a water plant. Of course as everyone knows water plants are extremely important to city’s. On a particular day, one of the workers inside of the plant (not one of my guys) went to isolate a line, and switch over to the bypass. The lines are 36” inches in diameter, and are at roughly 45 PSI, these lines are pressurized by a 6 Cylinder Detroit Diesel engine. ( There was some Cummins of course #bestdiesel) When the worker went to isolate the line. He completely turned the pump off abruptly , and hit the valve. This caused so much pressure in the line that the weld for the 2 piece 90• broke. The entire line blew apart, blowing out the glass window in front of it, and dumping tons of water. So much water, the entire pump house was filled with water up to your knees. Mind you this pump house was the size of a Walmart. There was electrical equipment everywhere, wood floating throughout the pumphouse. Welding rods, snuff cans, mtn dew bottles. This was caused because the pump was not able to wind down, the pressure was not relieved off of the line. It was an abrupt shock, and as you see in the video. The water pressure itself has no where to go. Because of this mistake the city was out of water entirely for almost 5 days. After the accident had taken place. My crew was on 16 hours straight. Working as much as we could to get new pipe flown in, welds welded out, and pipe fit up. It was an absolute nightmare. The plant went out and bought literally truck loads of bottled water and started giving it out to the general public. So the next time you hit a valve on, or off. Slowly turn the valve.
@practicalengineering @thisoldtony
sounds like someone needed to get fired and a career change if he doesn't know something like that as a pipefitter.
Sounds like the valve should have been designed in such a way that that could never happen. Always assume the user will do the wrong thing.
I work for a water company. An abrupt shut off can also cause a brief "no water". The water is moving quickly to a tank and when the pipes shut off the water is still moving and begins to slow causing a delay in pressure.
I want to add that at most water plants they have a clear well, a place for the newly treated water to sit for 30 minutes or so, so the chlorine in the water can do its job.. a clear well can be used as a shock absorber. That pressure from a quick shut off has an empty space to dump into. (It's important that the tank height is at or near the same elevation as the pumps)
The more you know..
eyescreamcake This information is out of my pay grade but thank you for the information!
If you want credibility online use your actual name. If some guy named "cheeseburger" tells a good story its probably bullshit. Cool story bro.
You want to super size that?
"There's actually another term for when a large spike in pressure ruptures a sealed container. A bomb" Your delivery is perfect Grady, thanks for the interesting content!
Thanks, Grady, for this (now three year old) video.
This really is "practical engineering" at its literal best. I've had an annoying "knock-knock" sound whenever my clothes washer ran.(edit: The "knock-knock" was the high pressure spike bouncing back and forth in the supply pipe.) After watching this video I immediately understood the cause, the likely long-term implications for my plumbing system and - most importantly - how to fix it. A few minutes of research, a $20 part from my local plumbing supply store, and ten minutes of work behind the washer - and problem gone.
It's hard to overstate how helpful it is for us non-engineers to have problems like water hammer explained so clearly and thoroughly. Heaven only knows how much expensive repair and maintenance your video has saved me, to say nothing about the annoyance of knocking pipes.
I'm never going to design a dam or a suspension bridge. But your series makes me respect the work of the engineers who do even more. I'm just glad to have put a bit of knowledge I got from your videos to use in a very common, every day problem.
Thanks for a great channel!
Newer machines usually cycle their valves in a way as to prevent serious water hammer. How old is your washer? Just curious.
@@16vSciroccoboi It's a fairly high-end Bosch machine, less than two years old. But there's more to the story. And it's an odd and complicated one indeed.
I live in the UK. For various strange reasons, most UK houses have a tank in the attic that stores cold water. Presumably in the event of a widespread disaster (ie. the Luftwaffe comes back?) this could become an emergency source of drinking water. This attic tank is the primary source of all the cold water in most UK houses. And being just a few feet above the living space, it's also the reason that the water pressure in most British houses is so pathetic. So pitiful, in fact, that there is a thriving business for plumbers and electricians to install "power showers" that use electric pumps to boost water pressure to a level sufficient to achieve a decent shower.
With me so far?
My house, unlike that of most of my neighbours, is quite new. And being constructed at a time when the prospect of Luftwaffe bombing seemed remote, it was built without the attic cold water storage tank. Meaning my washing machine, along with the rest of the appliances and other plumbing fixtures, receives water at mains pressure. Enough to give a very decent shower in my third story master bathroom. All good on the showering front. And plenty of storage space in my attic without that all-but useless cold water storage tank.
The problem is (was?) that neither the washing machine manufacturer, nor the the store that sold it to me, anticipated it would be receiving water at relatively high pressure. Meaning it was sold and installed without the $20 water-hammer arrestor that most US home owners take for granted (without really knowing what its there for). And that US plumbers install without a second thought.
I'm not an engineer. My father and grandfather were, but my eyes glaze over when confronted with the math required. I'm a behavioural economist. I make my living understanding and explaining why people do the things that they do. So I think I have pretty good idea of why my pricey Bosch washing machine banged whenever it ran. Thank God indeed for people like Grady to help me fix the problem. And thank you for asking the question that helped me answer it.
Hi, I got the same problem as your washing machine. Can you describe a bit more details, the part you need and how to fix behind the washer? thanks in advance
@@philipchan2378 OK: The problem was that during the parts of the washing cycle when the machine was filling, there would be a sharp "knocking" sound coming from the walls. This only happened right at the start of each cycle - not when the drum itself was turning. This was my clue that it was a water hammer problem.
The fix was a water hammer arrestor. In my case a Sioux Chief DW660-H. This was installed between the fixture on the cold water supply pipe and the supply hose of the washing machine. I checked ahead of time that the thread size (3/4" BSP) was correct for my machine. Installing it did mean I had to move the washer a couple inches further away from the wall. Installation (in a US/Canada setting): ruclips.net/video/aMd7bQ8kkj8/видео.html
Europe, etc. will be similar - just one arrestor instead of two.
Sioux Chief sells these parts worldwide, so I'd imagine they would be available to fit local plumbing and appliance standards.
In Europe washing machines generally have only a single (cold water) supply. In the US many machines have two - one hot and one cold. So you'll need two arrestors in that case.
If this is a water hammer problem, then installing a water hammer arrestor really is a DIY job. The only tool you'll need is an adjustable wrench capable of fitting over the flats on the nuts on the fittings. Turn off the water first, and be prepared to wipe up a few drops off water.
Last note: The flexible supply hoses on most washing machine are pretty durable. But they aren't immortal. And if they do split or get damaged it can end up making a huge flood in your house. Best to replace them (with good quality braided-metal covered) ones every ±5 years or so.
@@vrdrew63 This is such a well-written anecdote! I love it. Thanks for sharing!! I love practical engineering.
I'm a 2nd year apprentice plumber and you just helped me understand the dynamics of water in pipes even better then trade school did. My teachers taught us about water hammer but I am going to show them this video next semester because you described it in such a real life kind of way that it would help a lot of people wrap their head around the phenomenon. Water hammer always was a mystery to me but now I understand it way more now
It’s not often that I comment on RUclips, but I strongly believe in giving credit when credit is due. Your videos are excellent. Not only are they thorough, they are engaging and encourage a greater understanding of the world. Keep up the good work.
I had no interest in this, no idea why it was suggested. But now here I am enthralled by it. Are all his videos this good?
Benjamin Laporta Yes
True statement
Jude Salles, original.
TimGGleason yup
I study biology and I never thought this video would ever overlap with my subject but it turns out the water hammer effect is what makes heart sounds when the valves shut!
This should definitely makes you think that there is an engineer that designed our Heart. We are someone's system and God, Jesus-Christ, is the Engineer. The Ultimate Engineer!!!
@@grck4208 Then she flawed in the design.
Think my heartbeat sound is caused by the physical closing of my heart valves. Not from the ever so slight amount of Hammer effect cause by the slamming valve which would be adsorbed by the heart muscle itself. When I had a heart valve defect repaired a couple of years ago, being a retired Piping Engineer I had a long detailed conversation with my Heart Surgeon on this subject and we listened to the before and after ultrasound videos of my old and new aortic valve he had replaced. The Thump from closing was much clearer and comes at a point before there is any significant pressure in the chamber..
@@dwmcever You are a system (a complete unit) just so you know. Airplanes, cars, refrigerators, etc... are also systems. These systems have engineers, just like God is The Engineer who created you. There can't be a design without a designer. Airplanes, cars and stuff have wires that transfer electricity and stuff, just like us, humans have veins for blood circulation and stuff. Think about it. Please Let's talk. Hit me uuuuup!!! I love talking about this. I am saying this because I, myself, am a biomedical engineer, with a strong focus on programming of devices.
Where did God come from? Who engineered God?
As a 60 yr DIYer, I knew about installing anti-surge devices on water lines such as hot/cold to washing machines. But until your video, I didn't understand the science behind it. Thanks!
Water hammer is used in gravity pumps! Water flows freely out of a waste gate until it hits a predetermined velocity and a valve closes. The spike in pressure is diverted through a check valve which allows water to be pumped higher than the height of the original source at the expense of water lost through the waste gate.
Oooh. So that's how those work. I remember watching a video of one but I didn't understand the physics of it.
Cody's lab explain this effect and even make a pump.
A friend of mine built one of these to lift water up a large hill from a creek at the bottom.
It worked extremely well. I wish I had photos. He got the design from a ~1940's farming magazine.
Also similar to how boost converters in electronics work. The water vs electrons analogy is surprisingly accurate.
yes, just like a boost converter. even the equation in this video is analogous to an inductor equation and the step response graphs are the same as in LC tank circuits.
I bursted a pipe at my old job from shutting the mop sink valve as fast and I could over and over. I didn't know it was gonna break, I was just fascinated by the loud banging pipe sound traveling through the whole store xD
You discovered science son
You're fired!
Omg, so fired
Castin , don’t include that in your CV.
That’s why old job right
As someone who's worked at a plumbing company as a kid for a wile and remodeled houses for a living for years I did not know a single thing this video talked about. Learned a bunch.
Great presentation
Love your page. Definitely a follower @buddy's diy
yea those little hammer arrestors he mentioned literally do close to nothing. make sure you have a working PRV and you're better off. its not the slamming shut that's hurting people. its the fact the cities keep expanding and the pumps are putting out more water and increasing pressure. many people got notices in the mail about this. only had one call in 10 years where someone followed up on it to get one installed. soon as it was put in. hammer gone. pressure under control.
Knowing something is one thing but to understand it is a whole nother world. That's why I stayed away from technical, fear of understanding new things. With great knowledge comes great responsibility lol
I am no plumber, but I plumbed my house and for the hammer effect, this can be stooped my simply adding a larger capped pipe over the water line, this will act as an air cushion eliminating the surge. although after a long period of time they will need to be drained.
as a physician who loves to watch engineering videos, thank you for finally defining for us what a water hammer is (it's the question every med student has when they learn about the "water hammer pulse" of aortic valve regurgitation... just what the hell IS a water hammer?)
Dammit, now I have to find a video on the water hammer pulse
and here i am trying to figure out what water hammer effect causing acute traumatic aortic injury is .
There's a Consultant Heart Surgeon in Ireland that firstly started working as a young lad, served an apprenticeship to become a Mechanical Maintenance Tech in the Guinness Brewery Dublin, then progressed to being a Doctor and then onwards to that current new role ... asked about Heart Surgery he said, "Er sure isn't it all just Plumbing"...
@@malachy1847 that would be the Irish wit!
@@malachy1847 Irish understatement and humor.
"I mean civil engineering exciting, not like actually exciting." put that on a T-shirt.
I died of laughter when he said that!!
Time stamp?
@@Greengoblin2345 3:02
@@Greengoblin2345 3:01
what does that mean?
I've been teaching apprentices this theory for 40 years (or trying to) but these days very few engineers understand the importance of pipe sizing and the important result of velocity reduction to a maximum limit. That just leaves the two of us who seem to care. Keep up these brilliant videos. Thank you.
Small pipe = space efficient, not an eye sore, cheaper to make, fits inside any wall, gap, etc. Big pipe = don't go boom when someone slams the valve shut.
Besides the other 5 million people that have watched this video 🤣
We use this principle in the oil and gas industry as flowback operators. When coil tubing/Workover rig gets stuck by debris we will use a water hammer to try and free it. In this case the extra pressure can go into the formation but you still run a chance of splitting casing if you do it to hard.
yes, civil engineering definitely deserves much more recognition than it receives. Greetings from Mechanical Engineering
Funny how he said it's more of a civil engineering thing lol, it's more mechanical concept actually.
I like how much similar this is to something I've been dealing with recently in a project : voltage transients in electrical circuits due to inductive components (also called "load dumps"). When closing the valve/disconnecting the electrical load, if the rest of the circuit of pipes/wires is big enough to have a significant amount of inertia/inductance and there is enough mass of fluid/current flowing, it might cause a sudden and potentially damaging spike in pressure/voltage. It's awesome how hydraulic and electric systems can be compared and how one can understand one better by studying the other.
Great video as always!
Totally agree. There are so many good analogies between closed conduit hydraulics and circuits.
HerrHeisenheim I was thinking the same thing. In a way, the flywheel here acts just like an inductor, resisting any sudden change in current (di/dt). When someone first explained to me that an inductor is like a water wheel and a capacitor is like an impermeable but flexible membrane, it immediately clicked for me.
Thanks for the link, very interesting!
Your explanation might be great for students who need to learn the concept of Bond Graphs. It's a way of modeling dynamic systems independent of their physical domain. You just described how an electrical circuit can represent the behaviour of a mechanical system. Their bond graph representation would therefore look exactly the same.
How about something simple like synchronizing generators and a power grid in a 3-phase system? There is a simple indicator - you hook a lamp across the switch; when all three lamps are OUT, you throw the switch. We had power benches in Undergraduate Power Engineering where you got to do this. But it's counterintuitive to throw the switch when the lamps are OUT. If you throw the switch when the lamps are ON, you get a, well, big noise. And your intuition is fixed forever...
"I mean civil engineering exciting, not like actually exciting." Ha ha, don't all people find stuff like this exciting?
Lol, favorite part of the video.
But yes. I find all of this exciting. That's why i'm watching.
I'm a civil engineering student; I was laughing so hard when he said that. So true.
Thumbs up and a subscribe just for that joke.
Apparently I do. This is fun
civil engineering can get actually exciting but that usually means something went actually wrong
I'm a medical student and I came across this video because I was studying water hammer pulse. And I just loved this video and how it explained the dynamics of the condition.
As a vascular surgeon, I find this highly relevant and interesting in my line of work. Very informative video. Thank you.
Please elaborate
But veins are compressible and elastic right? So how does that play into thing?
@@JimmerJoMoore sustained high pressure will eventually create weak points and bulges.
Search how aneurysms form.
@@JimmerJoMoore blood vessels are pipes with pressure in them. Arteries are high pressure systems and during trauma there is a sudden change in pressure resulting in burst of the arterial wall, just like in the video. Despite being elastic enough. With age and smoking, calcification forms and makes the arterial wall stiffer, making the effect even more prominent, since the artery doesn't comply the slightest with the pressure.
As for the veins, they are collecting ducts and low pressure system and also elastic and compliant. Hence high speed trauma doesn't affect veins the same way arteries are. They just behave differently, and they don't get calcified (not fully understood why).
@@bobdrooples that is Laplaces law, and not exactly similar to what is happening in the video.
Dental student here, so clearly not an engineer. Just wanted to say keep up the awesome work man. You make top tier videos. And if I can speak for others, you are 100% inspiring kids to get into stem with these. Practical, fascinating, and most importantly not patronizing.
Looking forward to the next vid.
Chris Meyer you should get a set of noise-cancelling headphones ti play these videos for geeks to distract them drilling discomfort
Hey, man, my dentist is a mechanical engineer and a ceramics engineer and a plastic resins engineer and a metallurgical engineer and when he's not re-engineering my jaw and other people's jaws he's teaching new dental students...
You have enough science education to understand this or will.
Plumber here, my guys will be watching this in the morning. I appreciate well put together materials like this
Yeah what else do you have collected?
I wish he would've showed a typical expansion tank used in the average home. Its something most people don't know the purpose of.
Caramon Majere my plumber installed one in my house but didn’t adjust the air pressure. Even I knew your suppose to adjust the air pressure according to your water pressure and I’m no plumber.
@@whatfreedom7
Good chance you had the "Helper" doing the work under his boss' license.
I became an apprentice plumber at 19 years old, I'm in my late 50's now. Awesome explanation and demonstration of water hammer, I know that it can raise pressure in a line, but didn't know that it could get that high... Dang!
Could this be what is causing extremely loud groaning in our pipes (intermittently) when flushing the toilet?
I got into my apprenticeship right after high school at 19 and I love it can’t wait till I have my license I’m in school for
In civil defense (makeshift installation & repair) we used the water hammer effect to fill elevated water reservoirs from a water flow at ground level ("hydraulischer Widder" in German, a combination of a flow-operated closing valve and a holding valve). A bit noisy, but effective.
This is also a topic of research in nuclear engineering! Critical for fast shutdowns.
eL3ctric it’s also used in aircraft hydraulic systems.
It's also used in electrical systems.
Interesting things occur when you have coils being controlled by a computer. There is a reason many of those coils have LEDs on them.
Yes, but water hammer killed three men in the only fatal accident in the history of American nuclear reactor operation. Make sure you don't have any voids during shutdown maintenance operations, and you will probably be safe.
NavySturmGewehr. i don't see how that has anything to with what you said before.
Can you use water hammer to drive in liquid nails?
Well yes, but actually no
Randy Bard whut
Yes...but I usually just use a caulk gun for liquid nails
Obviously none of the replies before me understand construction related humor haha
Take my like and get the hell out of here
My old man was a plumber from back in the cast iron pipe days. As a teenager & young adult, I helped him with his swimming pool service side hustle but I never learned much from him about actual plumbing. I always had huge respect for his profession & the quality of the work he did. With the knowledge I acquired from this video, that respect just got even "huger"...
👍🏻
Thanks for your informative videos!
👊
🇺🇸
Our engineering firm works a lot with pipeline design that does a lot of transient water hammer calculations. This is one of the best primers to this topic I've seen and from now on I'll be having our new engineers watch your videos to help them visualize what's going on. Keep up the good work!
loved it. excellent demonstration as always!
Can't wait for your next video dude :-)
i was expecting a machinist joke about civil engineering but hey its you
Just this evening I was moving a water line for our cows. I opened up a 250' length of poly hose to check that it was on, saw that it was, then turned it off--then it lurched 1 foot forward! I tried it a few more times, and it kept doing the same thing. I wanted to learn more about what happened. Then I forgot about it, hours later went on RUclips to watch an episode of This Old Tony, and this episode title was recommended on my front page. I watched it, then I saw this comment. A little eerie, but Thank you and Practical Engineering anyway.
117th like you know masterchief hahaha that's funny!!!
Guys ugly kid is back
Thank you Sir, I'm in my 50s and through videos like these I still learn things every day.
so did I :)
Damn nice.
Same here. 😊
As a firefighter we get taught what a water hammer basically is and how to avoid it. I’ve seen many times attack hose jump up, down, left, or right because someone shuts off the nozzle quick. But this was cool to see it a bit more in depth.
You helped me understand what were some structures in my home town made for. I had never expected them to be made for this purpose. Thanks for making me fall in love a bit more with civil engineering.
Grady, please don't ever stop making these videos! No matter what it takes, please keep producing content like this. I'm in no way an engineer, but you constantly present topics that, at first, I'm not even aware of and don't have any interest in but by the end of the intro I'm completely engaged. We need more people to get interested in civil infrastructure and you're doing a fantastic job facilitating it. 10/10, always recommend.
Damn, I just witnessed this in my work.
We had complaints of extreme pressure surge from a ground level water-customer.
That particular pipe was connected to a main *before* a pumping system that leads to a 15 storey water tank, where the water then flows by gravity for the building. That pumping is controlled together with a "solenoid activated pilot valve", when they detect that the 15 storeys water tank is low in level.
Apparently, the automatic valve closed too rapidly, causing the water behind the valve to slam against the back of the valve. Which of course, results in Water Hammer! But in my case, the ground level water customer's pipe is connected to the main *before* the valve.
Meaning that when the valve slams shut, the water, instead of slamming like water hammer, it finds the easiest exit route, which unfortunately means the ground level's service pipe. The water pressure more than tripled when the valve slams shut.
@ Dalziel45 I believe you will find the Water Tank is under pressure as well. IF it was 'purely' gravity feed the users on the 14th floor would have Extremely low water pressure.... BUT, you are right about the pressure surge...They either need to add some type of surge arrester OR 'Perhaps' replace the solenoid valve with a check valve, which close 'Once' it senses low flow (ie. the pump shut off) while Still preventing 'Back flow'.....
@@crazybob1954mo re: pressure, not at all, depends on the size of tank & their min level and a few other factors. We absolutely can't tell just from that.
Though it'd have to be a 70 ft tall tank by my reconning- though if the water tank is 15 stories- 225ft above the building as you could interpret op.
There's even a bunch of low pressure systems around. I've not seen everything, but i've seen enough to know someone's gone and done it. It might not be to spec in our countries, but i'd take .3 bar over no running water.
You likely aren't wrong, but its never worth assuming anything, especially good sense.
@@mandowarrior123 Hmm Just What do you recon I am assuming?? You, on the other hand, recon the tank would be 70 ft tall... On what information is this assertion based??
Also you 'Think' a 15 story water tank is 225ft. Surely this is not an 'assumption'... ??
I do not know what country you live in, though I would not find the water pressure in my home being .3 bas as acceptable. >;)
Also as to your first statement... pressure does Not depend on the size of the tank... The height of a tank may impact water pressure, but Not the size. Hmm, Soo Much for Assuming, eh Warren
Good Day to You, Bob
M.E. working out at Hanford here:
We have high concern over water hammer (Fluid transients). We transfer radioactive waste, so we do not have the margin of error for transients that exceed our allowable stress for pipelines. One thing to note is that we don't normally rely on PRV's (Pressure relief valves) to mitigate the pressure spikes.
We have strong evidence that PRV's tend not to have a quick enough response time to relieve the elevated pressure, and hence we do not rely on them for safety. All applications are different depending on the working fluid. In the case of hazardous fluids, most of our solutions are based on aqcuiring valve actuators with the required closure rates.
A good resource (for anyone interested) is fluid mechanics, water hammer, dynamic stresses and piping design by Lieshar.
Great videos as always! I've been watching since I was in university (2015).
Nice explanation. My dad didn’t explain water hammer to me (he was a family doctor) but he did always teach me to be gentle with mechanical systems, tools etc, which I think goes a long way to helping things work well and last. Thanks for a really clear video.
You could do an entire follow up video just going through some of the anecdotes in the comments alone. I love seeing people share experience and knowledge like this
Water hammer is one of the first thing we teach new Fire Engine pump operators when they start. Valves 4in and above on our trucks are mostly electric gates so they are not a problem, but 3in and smaller valves are all manually operated ball valves... even with the build in protection of a by-pass, slamming those valves shut can seriously damage the pump.
Pat D they can also blow fire hydrants out of the ground if they are closed fast enough! I was told that has happened before and to take your time while closing ball valves attached to a hydrant
Some municipalities require any connection to a hydrant to go through a special valving arrangement to protect the system. It wasn't uncommon to see water trucks on construction sites ignore this requirement, as the valving reduced flow.
HAHA yeah, in our fire service we used to remind the new guys with "STOP! Hammer time!!!" when closing hydrants.... Thames Water would kick our asses if we bust one of their water mains!
Firefighters are the worst offenders for water utilities, they are the ones the break the mains in the ground most of the time, especially due to their arrogance.
What a bunch of bs, it might be that inexperienced men will cause some accidents because they still lack the training but it's definitely not arrogance that causes those incidents.
As a volunteer firefighter who's been in the service just over a year and a half now, I've heard _a lot_ about Water Hammer during my Basic Exterior Firefighting Operations (BEFO in NY) and Apparatus Pump Operator trainings, but it was never really explained well and only shown once or twice what the end result was; That being a sudden and terrifying explosive decoupling of both a 5" Supply line and a 2-1/2" Attack line from a Pumper/Engine. I'm glad to have found your video explaining in detail what's actually happening to create the hazard that I've been so thoroughly warned about but had little of it explained in such detail.
Thank you for the video. I am a doctor and was introduced to the term "Water Hammer" as a Medical Student back in 1997 (way before the Internet, 2G technology and hand-held touchscreen devices became household items in India) as a definition of the nature of the pulse in Aortic regurgitation (& a few other conditions). We were explained that the "water-hammer" was a toy of yesteryears, that delivered a sharp knock. We had never seen a water-hammer and neither had our teachers, so the curiosity remained how it worked. We had to accept it at face-value.
24 years later, I know finally, thanks to your video. A big thumbs-up to you and your efforts !!
Me too
This helps in understanding water hammer pulse so much better
There has been many a pipe blown apart by the use of butterfly valves (which have a habit of snapping shut due to flow) rather than gate valves (which are physically impossible to close quicky). I remember a certain coal power station where the valves returning water to the cooling ponds had originally been spec'ed to be butterflies. One day the header behind them blew apart in spectacular fashion when several valves snapped shut in unison.
Another interesting design aspect of town water distribution is the concrete blocks that surround every corner in the distribution network. Think of where you see a pipe emerge from the ground to cross a river (sometimes attached to a bridge) - there will be large concrete blocks that anchor the pipe at ether end to spread the forces imparted by the momentum of the water as it rounds the bend in the pipe.
Can you explain why the butterfly valves slammed shut? Most larger valves have a gearbox type actuator which I assumed would be unlikely to fail due to normal flow.
Those concrete blocks are usually refered to as thrust blocks, or if they physicaly encase the pipe they can be called thrust collars.
I have a 36" water main at the back of my yard, with a 90° elbow set in a thrust block. That block of concrete is 12' x 12' x 8', with the top of the block roughly 7 feet below grade.
You also see them at the bottom of a penstock right at the powerhouse.
Lee ... I'm surprised they didn't design the butterflys (ies?) as the "fuse" element. Did they, and was the header compromised somehow? Doesn't sound like a very smart design from a human safety point of view if anyone operates near them at any time. I would also think there could be easy design mods to the butterfly valves themselves that could cause them to fail open, rather than closed, even if they did separate themselves from the control (ie. "flapping" in the breeze, so to speak).
Great video! We stress avoiding water hammers to the new guys at the firehouse all the time. Opening/closing hydrants and nozzles slowly. Now I can better explain to them what's going on during a water hammer rather than just say "it's bad, don't do it"
I just wrote a comment on the same thing haha. Good to see a fellow Firefighter :-)
We had an engineer shut off the flow to a 2 1/2 inch line rapidly one night and it brought the water main right up out of the ground!
This is true particularly with high flow and large lines but firetrucks are made to withstand water hammer of attack lines. Although it will cause lines to jump around and on older equipment can send extra preaassure to other attack lines.
It's common practices to quickly pencil fires with shots of water when in extreme heat conditions particularly while interior, it reduces the effect to the thermal layers while preventing flash over.
You are doing a great job
This is one of the best explanations I have seen for water hammer. People think it’s just annoying to listen too, but it can cause catastrophic failures with a plumbing system.
Awesome explanation. There should be an introductory video like these every time a topic is started at class before discussing the theory. Theory can be invisible, impenetrable and considered useless without such good visual and practical videos like this one.
I love how you mention things in a way that makes me think "well duh, that sounds logical" and yet concepts I'd never think about had you not mentioned them.
Kudos, great and thorough explanation. I especially liked the contraption you made to visually present water hammer in practice.
I love when I don't understand something and find your videos at the top of the results. It's usually the last video I need to watch, even though I'm no engineer.
This is my go to channel whenever i encounter a term, a name, etc relating to systems that i don't understand, understand a bit or i'm unfamiliar with.....this time it's related to micro hydro electric generating systems.
Thanks Grady 👍
I came here to learn more about water hammer. This morning the hose to my washing machine burst. It burst around 5 AM when the sprinklers cycled on and we didn't go downstairs until 6 AM. So the water gushed in the laundry room for about 1 hour. Some areas of the downstairs floor were submerged under about 1/8" of water. The water ruined the carpet and some wood flooring. Water found its way to my garage and ran down our driveway.
1:28 "sometimes you'll even hear this shockwave..."
*keeps playing music and talking over the video clips so I can't hear it*
SimMaster This is Impractical Editing
Yeah I didn't like the music playing
The clip was there for visual aid; he's describing what it would sound like if his sink were to have an audible shockwave.
@@Momohhhhhh - Yes, but if he didn't have the music, he wouldn't have to describe that, nor would he be talking over it.
@@TheMrVengeance I dont think you can actually hear it in the clip. So he is just describing it
I had a water hammer incident a few months ago. Shut off the bathtub faucet a bit quickly and the feed line to my toilet tank burst off, hosing down the whole bathroom. Now that I know the name of this phenomenon, I might be able to search a solution. Thanks for the helpful video.
When I plumbed my house, I put in capped lengths of pipe sticking up when I put in the showers. They house air chambers that will absorb the shock. I'm not a plumber, but I thought this was kind of a standard feature.
Jimichan may be a standard modern feature, but my house is a bit old and it seems my plumbing, much like the wiring, is a bit janky...
Jimichan One thing to be aware with that solution, is there overtime the air trapped in those standpipes will eventually be absorbed by the fluid under pressure, kind of like carbonating a drink, although atmospheric air is more resistant to dissolving in water than carbon dioxide is.
You were right, that that used to be a standard solution, but what I just mentioned was also a standard problem. Which is why modern plumbing uses something like the device he showed, basically the same thing, except there is a rubber membrane containing the air inside so that it doesn’t eventually disappear.
The solution to air disappearing in the air trap is to drain the entire system and then when you refill the system, air will remain in the traps. It also seems like you might have to clean the traps if they get dirty.
Expansion tanks and well pressure tanks will also help. Literally just a giant air trap but has a rubber bladder to separate the air and water. Its required in well systems, which was common in a lot of older homes. They do go bad over time, mainly the rubber bladder. If your house was converted from well water to city water, then you will have to adjust the rest of the plumbing to accept not having this tank if its removed.
TheGhostFisher Water hammer from a quick shutoff can damage the solder at the metal/copper connections. Trust me I know!
"There is another name for when a spike in pressure rupters a container, a bomb" why did that make me laugh so hard
It got me too, was like 3/4 listening so it made it even funnier than it should have been.
Kudos for not showing ads at the start of the videos, I actually see your ads because of that
I wish I had a professor like this during my undergraduate time! One of the best RUclips channels for sure! Success.
Water Hammer - Keeping haunted house detectives employed since the invent of running water.
Alex that and fire hazard wiring.
Alex advent or invention
Medical science is improved.
No surgery is necessary.
Do you really want to raise the dead?
@Thomas Chrombly Spirits work in mysterious ways!
Coming back to these older videos after watching your more recent stuff, it's fun to see how your channel full of very polished scale models had its roots in rough hewn 2x4s C clamped onto cinderblock and arduinos hanging from water pipes.... I almost miss the rustic charm!
I'm dealing with a water hammer situation at my parent's house. I rewatched this to be sure I have my info straight. Thanks!
"Just in case something exciting happens...
I mean civil engineering exciting. Not actual exciting."
Haha, love it!
Honestly, I thought you made a video about using water as a hammer! XD
PS loved your videos.
Blaze23 pb
well, this is a video about using water as a hammer, in a way
Holden Caulfield well literally doing it would be, freezing it into the shape of a hammer.. XD. But yeah you're right.
there's a video from Primitive Technology that's a bit more literal: /watch?v=i9TdoO2OVaA
Damn I was going to link to the same video. When I read "water hammer" I took it to mean something along those lines. But this is pretty neat too!
I was thinking about the primitive tech video as well
I tell you that I am not an engineer but as an electromechanical technician received many years ago in that country called Argentina (for 37 years It's became in Argenzuela) in the industrial schools they taught us all this that you have just explained in an excellent way.
Thanks for the video that has refloated some concepts that had been very archived in my mind.
Greetings
Great vid! Solenoids closing a valve tend to act quickly. When reno-ing a house I owned, replumbed with CPVC, like the video, I added spring loaded anti-surge devices by the kitchen dish washer, clothes dryer and end runs to the bathrooms. I did NOT just add an air "T" as, over time, the air can be absorbed by the water.
Excellent, Grady! Thank you for helping us understand this and all of the other concepts you've made videos for.
Yay another video from u :D love your demonstrations!!
Regardless of age, I love seeing stuff like that
The way you said that
Comment Police lol it could be taken 2 ways with the age comment couldn't It?
Of course
Well today I learnt something both completely new and something that I have experienced multiple times that may shape how I interact with taps in the future. Thank you, its not often I get to say that!
Very clear explanation. I've got this problem with my apartment's faucet and find your explanation and recommendations very useful. Thank you
Harness the power of water hammer... and you get a RAM PUMP! I am super fascinated with ram pumps at the moment and currently doing all the research I can on them.
In 2016, we bought 18 off-grid acres on a mountainside in VA, with what we first thought to be a fairly useless creek at the base of the property.
Recently learning about the details of water hammer and how ram pumps harness this power, we've come to realize that our creek is NOT useless, and we're certainly not going to allow its potential to
go to waste now, if we can help it! First, we've got to put together a system to pump an adequate flow rate (for cob building, gardening, aquaponics, and raising livestock, etc) to push enough water nearly 300 feet straight up, and about 2,000 feet in linear lenth, with the creek's dropdown of only between 3 and 5 feet at the very most. Can we get water hammer to work for us??
Thank you for all of your wonderful and helpful videos! ♡
As a former US submariner, this was a delight to watch. Keep up these great videos!
Great info for those going offgrid .Thank you for the simple clarity of this video ,looking forward to learning more
My god you explain things so well, and produce brilliantly edited videos to illustrate the concepts. Thank you!
You are awesome man. The videos you make are great and at the same time simple to understand.
I may be a commercial rough Carpenter, but I like learning about the other trades, and I've always been curious what those water hammer (brand name) devices I see getting installed in buildings were
So true
Hey Grady I’ve been a Lic plumbing contractor for over 20 years and when I’m plumbing a home at every fixture that has a cabinet I always stand a tee up and simply add 8” or so of pipe(usually pex) just before the stops and always make sure all the piping is really secure. Similar to your water tower example. I’ve never had a call back for hamming. Thanks for this video
I'm not sold on PEX materials yet. I see the installation benefits but do not see the benefits to the homeowner.
@@Garth2011 yet? It’s been used for over 50 years. The benefits are cost and durability to name a couple. When I plumb a home I do not have any fitting from the mechanical room to the fixture I run straight pipe from my manifold all the way to the fixture that Illuminates any possible future leaks in any crimped fittings and also each fixture can be isolated for repairs or replacements. My manifolds are labeled with a shut off for each fixture. If there are any problems with pex. it’s not the product is the installer you have to make sure your crimp tool is always calibrated properly. Lots of hacks out there
@@jiggidyjam It's been used for 50 but not in California that long. at first it wasn't rodent proof and the fittings weren't perfected and as you said, the installer has to be on his mark at all times. They do use it here now a days but if I were building a home, I'd using copper I think.
I have seen installations where they used all home runs to a large manifold in the garage for example. Nice set up and nice to be able to control one room vs. turn off the water main for service etc. On this home, a tract in an HOA, the plumbers had zero future in mind for the homeowners. They terminated the PEX at the toilet and sink connection so, no angle valve, no rigid fixed PEX etc. it would exit the drywall and wiggle like a cheap temporary idea. So if there was a leak or a reason to turn off the toilet (plugged up), they can't quickly. When cleaning their toilet or servicing the bathroom, there are no valves to shut off the water without going into the garage. Lot of folks use those valve when performing cleaning or maintenance. Yes I understand it can be done in the garage but the idea seems so temporary and limited, nothing about those fixtures was rigid, seemed like a mobile home quality install. I'm sure there are better methods but it seems that house was full of shortcuts when it came to using PEX and fittings for the homeowners sake. Then, we have additions later on, mods to existing plumbing etc. that will have to be delt with experienced and well trained plumbers plus their special PEX equipment. There's more to a home plumbing job than the day it is signed off by the city inspector...modifications are likely, needs change etc. and PEX seems less adaptable to that vs. copper.
@@Garth2011 again your argument is about poor installation. I’ve installed hundreds of pex systems with zero call backs and my stub outs with angle or straight stops aren’t floppy. Also copper is just simply to expensive and isn’t necessary. I’ve used pex for a long time with brass fittings from day one. I certainly hope you’re not confusing pex with polybutylene (grey pipe with plastic fittings) cause that is junk!
@@jiggidyjam Most plumbing concerns are about poor installation. Workers who claim they are qualified and in the know of plumbing needs and features. In fact, most of everything that turns into crap is due to poor workmanship, providing the materials are good. It's everywhere. Obviously you do not cheap out on you rplumbing jobs, I've seen so much crap out there I rarely trust they know how to do great work. Too many of them have a license and they shouldn't.
I learned about water hammers recently as a volunteer firefighter with regard to making sure we don't open fire hydrants to quickly and damage the pump truck. Getting a more detailed explanation on it was really cool!
I was also taught to not close the hydrants too quickly to prevent damage to the underground water lines.
I really enjoy your videos, you seem to have a real nack for simplifying these ideas for those of us outside the feild. Also I really appreciate you have subtitles for your video s.
I'm in firefighter training right now, and on one of my first days my chief told me to go "grab the water hammer from the truck". Luckily I knew what it actually was and avoided embarrassing myself!
And remember not to charge the line too quickly.
I have observed this more clearly with following case: long hard pipe (about 25 meters) with open end and valve in the beginning of the pipe. Open valve fully and wait until water flows as fast as it will. Then close the valve fast. Water will go on and vapor bubble forms right after valve. Soon the water comes back, bubble collapses and it was like hammer hit in my hand holding the valve which was not attached to anything solid. Did not do this in purpose and wont do it again. Great video as others by Practical Engineering
Edit: ... and you have made a video about that already.
Wow man. Super clear. Loved the video. I'm a med student and I didn't understand the "water hammer pulse" and I now I do. The air bladder also explains the Windkessel effect in the aorta. I'm glad I found your video.
I love your videos. Engineering is very addictive to me. even though I know many of the concepts to teach, there's always new things I haven't thought about it. Like the overall math behind water hammer. Keep up more videos!
First of your videos I've seen and I'm loving it! Very well made, seems like a lot of care has been used to create what you wanted from it. Keep up the good work dude
this is the best water hammer phenom explanation i've ever heard. - Thank you!!!
i found this channel at 1 am....it is now 4, his explanations are very clear and methodological !!
I've seen 4" copper pipe look like a snake when someone opens/closes a valve to fast. At 20 feet up in the air a bit of a pain repairing the soldered joints.
kleinjahr copper in particular MUST be secured along its entire length to avoid any movement.
kleinjahr
Who solders 4" copper?
Theweescot
Secured along it's entire length?
Theweescot Aye, that was also a problem and what the codes are for. Which was pointed out to management.
John Perdue Sometimes in older plants you run into odd things. I’ve even run into old knob and tube wiring, still in use.
Love these videos so much! This channel had no small part in my decision to study Civil Engineering at university.
Good luck.
Every time he posts a new video, I consider switching from electrical engineering.
inductive kick, inductive kick! your field has the same thing!
Watching this made me wish I had gone into Civil Engineering, interesting stuff.
It's nice to see the pressure difference with the mini-rester. It helps even if the hammer doesn't completely disappear. It's connected right next to an automatic pressure-activated hose timer. Prior to putting the mini-rester on, the boom was pretty audible with my cast iron piping!
Very good! Helps so much to understand how it all works and why before just “treating the symptoms.”
Absolutely fascinating, sir. This has truly shifted my perspective about plumbing/our way of living altogether. This information has connected the dots for me in one or those ways that you understand something to be true but never applied it to areas where it carries more weight than you ever dreamed or being relevant (although barely there, there was no pun intended) I hope that's not too vague of an explanation about why this just made me so happy/excited/totally nerd out lol
I didn't see or hear about the most common source of water hammers in a multi-pump system (more for mining/industrial slurry) which occurs when the horizontal water column is separated by vacuum because of pump start timing and/or vacuum occurring in the primary (first in the system) pump suction. These water hammers have nothing to do with closing valves, as valves typically are not installed in such systems. Such water hammers are actually cavitation at a very large scale.
The water hammer occurs where the separated water column collides. The part of the water column ahead of the vacuum is flow-restricted by the components of the system (pipe friction, directional fittings, pumps, etc.) but the part of the column behind the vacuum doesn't have those same restrictions, with the flow being increased by the vacuum. The pressure wave from this collision reverberates in both directions inside the pipeline, but is stronger in the direction of flow. The intensity varies with the distance the column is separated by vacuum. I've seen pump face-plates blown all the way across the access road by these water hammers.
I’ve been selling plumbing supplies basically my whole life and this is a great explanation of the causes of water hammer and how to mitigate it. One of my customers just finished a restaurant and I wish you’d been the engineer on it
Great video to improve my English. Rich vocabulary, few idioms, words correctly and well pronounced. And, of course, a very interesting content.
Washing machines and old plumbing... Washing machines are some of the biggest culprits for this in the home because many solenoids shut the water off very quickly. On plumbing that is installed without buffers or arrestors, the hammer effect can be quite noticeable!
Builder Dex I just saw one with a hammer arrester on the pipes that didn't do enough. I suspect the city bumped up the pressure again to use increased lressire to shore up old water mains. Some cities get sued for this when appliances break, pipes rupture, and hoses Flood (when homeowners eventually figure it out). A good pressure regulator being adapted down to the proper pressure by a plumber is usually enough to save them if they don't wait until it's too late.
You're not kidding, we bought a brand new LG top loader, all the bells and whistles , connected to the wifi ect. LOL, but holy crap that shut off so fast the water hammer sounded like somebody dropped a huge safe in the basement. Never heard of water hammer until that noise was apparent. Went out and bought a couple of those Sioux Chief arrestor's for the back of the washing machine and so far, they've worked perfect quiet, but holy crap they give off a serious bang.
@@Boswd Ya my LG is terrible too. Frustrating to buy a brand new whiz bang appliance and have it make such loud noises. I installed the arrestors on the back but they don't really make a difference. Of course no one at the appliance store knows anything about it or has ever heard of this. Pressure regulator is new so I know the pressure isn't too high. I've heard it's the digitally controlled valves used by LG...shameful, I should have returned the piece of junk.
@@EricS977 try the sioux chief brand there have worked great for us. www.acehardware.com/departments/plumbing/pipe-fittings/copper-fittings/44556. If that doesn't work at all your water pressure may be too high. Call a plumber and they can test it and install some arrestor s closer to the outside water source
@@Boswd Thanks, I have some type of small arrester that I installed years ago, not sure of the brand, but it didn't do any good. I saw a suggestion to slightly close the water valves behind the washer and I might try that to see if it works. We had the house re-piped a few years ago and a new pressure regulator was installed so that should still be good I would think.
I think I might have learned too much in a short amount of time. Hopefully I won't suffer "brain hammer." Thanks anyhow!
lol
Michael Graystone I recommend watching in 0.75 speed.
Michael Graystone I
Haha
This really is "practical engineering" at its literal best thank a lot
Very informative, scientific, demonstration is perfect. When I bought the house in 2000, the previous owner set the setting of the Pressure reducer to 80. All the faucet cause a knock whenever it was turn off. So I put the psi to 50 and it solve the water hammer.
The only man that can make a water pipe interesting as hell
Bruh 😂
Great video.. Now I understand the problems with my DIY automatic irrigation system :)
The high school I attended was in an ancient building- we were actually the last class to graduate from that structure. I often wondered who the heck was banging on the pipes in some of the classrooms with hot water heat. Now I know. Thank you.
3:02 is so accurate and funny. My wife will understand me more now.
Love your videos. Im a civil design drafter, and your videos put the interesting and fun back into my awesome career
Honestly surprised you didn't at least mention ram-pumps.. Using this property to do useful things, as well as demonstrate just how much energy is in the system.
Plus they sound and look cool! **ssssssssss*THUMP*PFFFTS!** **ssssssssss*THUMP*PFFFTS!** **ssssssssss*THUMP*PFFFTS!**
(Ok, and the gauge bending the needle was also very impressive too.)
Great video. Thanks for posting, I will be sharing it with clients.
I almost screamed when I saw the unsupported PEX pipe at 1:30. I see a lot of that here in VA.
I'll keep my mouth shut on the galvanized in that same shot.
And THANKS for acknowledging all of us plumbers out there.
The pipe was probably unsupported to better demonstrate the effect.
Alex Jamieson
I doubt it. I see pipe run like this all the time, hack "plumbers" and DIY'ers that get "help" from the stock-boys at sLowe's & Home Desperate.
But go ahead & make more excuses.
Frank De Mascio
Could you describe the proper way to route such pipes? I think I count as one if those Home Depot hack job peoples, and would welcome sound knowledge.
Oh but c'mon! PEX is God's gift to plumbing and shark bites are his apostles. It can do no wrong, watch how it handles being bent under it's own weight at the t-joint while under pressure. No more tyranny of 90° elbows and tight corners. Pfft, why have joints at all?!
In all seriousness, I see that all the time. rather than taking the time to run PEX as it should be and have it supported. People simply just run it haphazardly because the pipe is able to bend. PEX is great and easy to repair, but it allows people to be lazy.
Treat PEX like you were still running copper piping. Pex is flexible but allowing the pipe to bend and bow too much will still cause failures. It's just a matter of installing pipe supports to make sure the pipe is not bowing under it's own weight. In the video, the issue is that the pipe is bending right at the t-joint which does not bend. So there is excessive force right at the joint, a hard enough water hammer or someone accidentally bumping into it and the pipe will snap right there or the joint will fail. Just use common sense and you should be fine.
I normally dont watch ads but this guy and his content makes me watch it to support his channel in a little way because he has his ads at the end rather than before the content.
That was one thing that I never had stopped to think about, and I do all the handyman's work in my house. I had heard about it but did not sound important to bother. But man, this is very serious business. Thank you!