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WayneG1 (California)
Posts: 40
Posted:
This is more of an engineering question but maybe somebody has experience. Our building is 24 stories and 140 condos.
It is 55 years old and the copper drain pipes are rotting and constantly being repaired. As people buy these units and do remodels
They install clothes washing machines which are allowed by the architectural committee. The question is would there be some point where
There would be too many machines(which the building was not designed for) And could overwhelm the drain system causing back ups
And overflowing

AugustinD
Posts: 3,698
Posted:
Quote:
Posted By WayneG1 on 06/04/2021 7:03 AM
This is more of an engineering question but maybe somebody has experience. Our building is 24 stories and 140 condos.
It is 55 years old and the copper drain pipes are rotting and constantly being repaired. As people buy these units and do remodels
They install clothes washing machines which are allowed by the architectural committee. The question is would there be some point where
There would be too many machines(which the building was not designed for) And could overwhelm the drain system causing back ups
And overflowing
So construction was about 1966, right? Did the original construction include washing machine hook-ups? If so, then I suspect the sizing of the drain system is fine as far as washing machines are concerned. Circa 1966, I think washing machines on average used a lot more water than contemporary machines do today.

If washing machines were not originally installed, then in my opinion, you should get a civil engineer to comment. Alternatively, the next time a reserve study is done at your COA, ask the reserve specialists to have the engineer comment on this situation.

I hope you have a line item in your COA's reserve study for piping. From Aug 2020, this might be helpful:

A Condominium Can Last Hundreds of Years, But Not Its Components

A 40-year-old Honolulu condominium can show its age in many ways: brittle, leaking pipes; cracks in its concrete walls and decks; rusted rebar; and corroded railings and window frames.
Dana Bergeman is the CEO of Bergeman Group, a local construction management company. He says many of Hawai‘i’s condominiums were built in the 1960s and ’70s and are reaching the point where they will need major infrastructure, cosmetic and architectural improvements to keep their value and remain liveable.
...
Kimo Pierce, president of Hawaii Plumbing Group, says condo associations should start looking at replacing their pipes at 40 years and be ready to start the project at 45 years. Once the pipes hit 50 years, he says, a condo is “on borrowed time.”

Cast-iron drain, waste and vent pipes eventually rust from the inside out. That can lead to clogged and cracked pipes and, eventually, water leaks. It’s during the investigation of these leaks that contractors discover if the pipes need to be replaced, he says.

There can be millions of feet of pipes and hundreds of units in a high-rise condo, so the process to repipe involves a lot of coordination. Contractors hold town hall meetings before construction begins to educate owners about the project, its schedule and what’s expected of them. They also do a pre-construction walk-through of each unit to check for any preexisting water damage and to identify which walls will be removed and how they will be replaced.The cost to complete this work is generally influenced by the size of the building, how the pipes are laid out, the number of stacks shared between units and other variables, Lecky says. Pierce estimates that a one-bedroom, one-bathroom condo can cost $17,000 to $20,000 to repipe. That means a 100-unit building with all one-bed, one-bath units might cost $1.7 million to $2 million to repipe.

Bergeman says, depending on the building’s configuration, he’s seen per-unit prices range from less than $10,000 to over $80,000, but the typical cost is $20,000 to $30,000.

-- More at https://www.hawaiibusiness.com/condo-owners-beware-part-1/
MelissaP1 (Alabama)
Posts: 13,836
Posted:
If washers are allowed, then maybe request they be more of a low flow kind. I know my front end washer doesn't put out alot of water. Plus I would suspect it would take a bunch of people doing showers/washing clothes at the same time to cause an issue.

This would be a question for a plumber who may be more educated on codes.

Former HOA President
KerryL1 (California)
Posts: 14,550
Posted:
Are you sure your drain lines are copper???

Are they on your reserve schedule?? Your Board needs to consult with your reserves specialist about placing this component indoor reserve study.

Are you on the Board/

I'm not expert, but don't thin washing machines are adding much strain to your drain lines. If you building wasn't "designed" to have washers, what does the existing drain line in condo units serve???
MaxB4
Posts: 3,513
Posted:
Carrying water to the source would be through copper or Pex, but the drains will be with PVC or ABS. Over time, the solder connecting copper pipes tend to develop pin hole leaks.

Another thing to consider, was your building originally built as a condo or could it have been converted from an apartment. Generally, older apartment didn't allow for washer/dryers and the quality of construction was not as good as a condo. We had one such case in San Diego where the owner of the management company was also a lawyer and was suing the developer of the converted apartment for poor workmanship that led to major water leaks.

There may be provisions in your reserve study for replacing plumbing if the reserve analyst determined the useful life was less than 30 years. You might have a funding issue if it wasn't included.
WayneG1 (California)
Posts: 40
Posted:
great info, thanks
WayneG1 (California)
Posts: 40
Posted:
I am the building engineer. I attend all board meetings
The building was built in the mid 60s and converted to condos in the 80s
All the drain pipe is copper including the stack risers and then go to iron sewer pipes
There was no dielectric connections and there was severe electrolysis.
There was never any provision for washer hook ups
Some owners install the washers in their kitchens and tie into those drain stacks
and some in their bathrooms
MaxB4
Posts: 3,513
Posted:
Quote:
Posted By WayneG1 on 06/04/2021 11:15 AM
I am the building engineer. I attend all board meetings
The building was built in the mid 60s and converted to condos in the 80s
All the drain pipe is copper including the stack risers and then go to iron sewer pipes
There was no dielectric connections and there was severe electrolysis.
There was never any provision for washer hook ups
Some owners install the washers in their kitchens and tie into those drain stacks
and some in their bathrooms

I managed a property in Inglewood identical to what you just describe. It was a rat's nest of problems.

Best of luck!
AugustinD
Posts: 3,698
Posted:
Quote:
Posted By WayneG1 on 06/04/2021 11:15 AM
I am the building engineer. I attend all board meetings
The building was built in the mid 60s and converted to condos in the 80s
All the drain pipe is copper including the stack risers and then go to iron sewer pipes
Dang. Copper for drain pipe usage (back in the day?) confirmed by google. To me, there are two issues, which might overlap some:

-- Failing copper pipe, really unrelated to the amount being put down the drains.

-- Whether backups are occurring because of pouring too much down drain pipes.

WayneG1, is the building currently seeing drain line backups? If so, I'd be surprised if these were on account of the washing machines. One has to consider the "factor of safety" yada used for drain line design (IOW, drain lines are purposely oversized yada); the fact that washing machine use is intermittent and by multiple users at different times; and so on.

The net has a fair amount of chatter on corrosion in copper drain lines and what code says. As the OP likely is aware.

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