Vacuum breaker valves on tanks above the first floor?

Teemok

A customer of mine bought a property with a small commercial kitchen in it. To get a permit to operate the hot water had to be improved to meet health code. The single existing TK-2 in the attic wasn't cutting it. The gas line was maxed out and it was working well. The least expensive solution was to add a storage tank (40 gallon electric and SS 009 pump. Piping TK-2 as a volume water heater exceeded code draw with extra to spare. The inspector was new and a nice guy. He saw my unconventional permit and did some reading about tanks. He required a 1/2" vacuum breaker valve on the cold line. The logic is: if water pressure is lost and a siphon was set up on the cold side piping while a hot faucet is opened the tank could be siphon drained out. They want the drinking water to stay potable in the tank for emergency consumption. Also if the tank where high enough and there where large vertical mains connected the tank it could be oil canned by the weight the water in the lines should a lower faucet be opened. I have never seen a VB valve on anything under a 3 story building. I read the code and the way he interpreted its meaning would mean every 1st floor level tank water heater with a tub spout connected on the same floor or that has a foundation level hose bib below it would need this little leak monster of a valve per code. Every one of them could be siphoned dry under the exact same conditions as his fears for the tank in question. Hundreds of millions of them are thankfully missing in action. He didn't seem to get what I was talking about. I proved to him there is no risk of oil canning by shutting off the water and opening a hose bib. Nothing happened. I know it's not worth fighting the man so I took a photo of it after I did the extra trip detail VB install and he it passed. Has anyone been required to have a vacuum breaker valve for a water heater in a single story attic or on the second story floor serving a lower floors fixtures?

Mad Dog_2

Yes...You gotta pass, get paid, don't "die on that hill."   Some States' codes want a Vacuum breaker on all water heaters, period. Sometimes, if you can't get the extra $$$ out of the Client and as long as its not going to cause a Biohazard or explosion,, plug it.  Its can easily be put back in if needed..  Mad Dog 🐕 

EBEBRATT-Ed

Mass requires them all all water heater no matter where they are located. CT does not as far as I know.

Teemok

I can imagine the suits sternly lobbying for them at state level and the valve manufactures smiling rubbing their palms together thinking of the profit flow. How many gallons of water are wasted by the leaky clams? Every tank? Good solution for hens teeth most of the time. Reminds me of when the SF, CA plumbing chief decided all single wall heat exchangers must go. He and some coffee talkers imagined a danger scenario that must be mitigated to prevent all the sickness and death that is certainly happening right now. Lots of protecting and not so much serving. Millions of dollars in forced unnecessary spending and stressful harassment over a few years to only to be reverted when better judgements prevailed. Like I said, you could read our CA code as almost all tanks all the time but the vast majority of final authorities (inspectors) know that the expense and leaks are not worth the benefits in most use cases. Most of our counties allow the industry standard vented double check valve on a hydronics system fill line. The code is clear about requiring an annually testable/tested RP back-flow device. Some areas insist on it, others don't. I've installed a few boiler feed tanks on inspection to eliminate the potable connection and the recurring hassle and expense of testing and valve maintenance in the very scared of boiler water areas. It's non-toxic by law. That doesn't guarantee that it is no but weight the risk vs expense. No one wants to drink any obviously. Will it harm you? Probably not. Is there a problem with a watts 9D? Is it unsafe? Search for illness and death related to the dreaded boiler water.

mattmia2

Maybe you should push for someone to come up with a better vacuum breaker than complain about the code and usually manufacturers' requirement. A cylinder is very strong if you are pushing from the inside but very weak if you push from the outside. It would be difficult for the code to figure out exactly where there is enough force to damage the tank so any outlet below the tank requires a vacuum breaker.

Teemok

What do we want? Better VB valves! When do we want it? NOW!
Quality and valve tech aside your logic is: it would be difficult to know so blanket application is justified. Many millions of tanks live long lives with no VB involved. BTW the valve is not on the outlets below the tanks. Those valves have a different and valid job. The valve in question is on the cold inlet above the tank. I understand it would be nice to idiot proof everything but that gets expensive and wasteful. Responsibility for understanding where and why it may be needed is not such a huge burden or complex problem for professionals. If you are a tank manufacture building tanks so flimsy they collapse due to a 2 story water column vacuum maybe the competition of the market should do you in. Or you put the valve on your special tank. Problem resolved and no pointlessly mandated mass expenses and complications.

hot_rod

Another classic case of regional enforcement. It seems these valves are more commonly enforced back east for some reason. According to sales numbers anyways. Most of my plumbing careers was in western ststes. I've never installed a VB on a residential WH! Never questioned by a code official on the application.
Close to 50 years of plumbing under my belt.

If you look at any control valve or device for plumbing and hydronics you will find a sealing washer, seat, and spring, mostly.
Not a lot of super engineering to be had inside

Over the years we look for "slippery" materials as 90% of leaks or failures are directly related to the stuff and fluid that flows across, through, or against the sealing mechanism. So scale, dirt, silica, copper reams, teflon tape is what we see in returned valves.

Also, all the various materials used to seal have life expectancies, EPDM, buna, viton, teflon, silicone many other blends. Stuff wears out. More aggressive treatment chemicals used by water providers is also an engineering challenge for valve manufacturers.

But service techs make a living replacing stuff that wears out

In the more sensitive valve applications we use fine mesh Y strainers to protect components, fan coil kits, balance valves, etc.

Only so much you can do to make a "wetted" valve bullet proof.

The plumbers oath is to protect the health of the nation.

We do this often with various safety valves, pressure, temperature, back pressure, backflow .... That is not going away and requirements are getting stricter all the time.

Teemok

We would hope stricter would always mean safer but there's the old law of diminishing returns again. We pay and complicate and some times the fix is as bad as the problem. Idiot proofing at the all cost is always questionable. Trashing durable and simple design for a couple percentage points of efficiency requires a similar kind of logical judgment. Efficiency at any cost is a fools motto. In the VB valve case, oil canning is real and the knowledge of where and why to use one is easy to standardize given there's a minimum tank spec. manufactures meet. Do we make everyone do something to cover rare cases or make a few manufactures do something that's always good and saves us millions of brass leaking sticker valves. The second problem a VB solves is a fairly rare circumstance where you find an empty siphoned tank. Yes, It could save a life. I have worked with VB's enough to know they stick shut regularly so some percentage of them would fail to do their job anyway. Just because someone makes a living off of a dumb rule is not a great reason to continue with it. Having said that I know full well the direction of things. @mattmia2 might be right. If you can't stop something wasteful and silly you can make it a little better with superior materials and design and then profit from it.

Larry Weingarten

Hi, If the water heater in question was fed cold water via a fitting on the side at the bottom, the inspector might have had some ground to stand on. If it was supplied at the top, using a dip tube, not so much. All dip tubes have a small vacuum breaker hole drilled up towards the top of them. This prevents the tank being drained of water in the situation you described. One of the old books called it a "sneft hole".

Yours, Larry

Teemok

Man, I wish I knew that at that inspection. Sneft is the word of the week! I will be checking for the sneft holes. The nice and new inspector would have said: The tank isn't oil canning now but can you guarantee it never will? I didn't think so. Put the valve on to CMA. "I don't care if it's the only one for 100 miles in 40 years. I love the smell of authority in the morning."

Oh T-mo, shut your sneft hole!

German: nickname for a helpful or friendly person, from Middle High German senfte 'soft, accommodating'.

Urban dictionary:
Bereft of smell, as "blind" means bereft of sight, and "deaf" means bereft of hearing. The poor, little sneft girl passed by the chocolate factory, unaware of ...

Occupational name for a mustard seller, from German Senf "mustard".

......and there it is, confirmed:
Water Heater Rescue-
The cold supply pipe (dip tube) has a small hole (sneft hole) in it, towards the top. This acts as a vacuum breaker in case water pressure from the main ...