Riddle me this

[jbhenergy]

So here is the scenario: You have two rooms side by side, both concrete block, both have north side exposure, roof exposure, and on slab, not a single lick of insulation. Both rooms have plumbing, and a source of heat. one is heated by an electric unit heater one is heated (and cooled) by a RTU that also feeds other areas. The RTU is removed, because the primary areas it was serving are demolished. NO new source of heat is added to the 1 room to replace what was supplied by RTU.

Their reasoning, "we figured the heat from the next room and the hallway would keep the room warm enough that we wouldnt need to add a new heater".

I swear when someone get the letters PE behind their name, they become very......... ill bit my tongue for fear of retaliation.

How in the heck, does enough heat move through concrete block walls, to keep the room next door from dropping below freezing when its 9* out? Let alone, the room is a bathroom with no heat source. Who the heck wants to go sit on a 40* toilet seat and take a dump?

[WAYNE3298]

Depends on the size of bathroom, exhaust fan size and heat quantity available from adjoining rooms. A lot of small commercial toilets are heated and cooled this way but not if walled off. They normally have a through wall grille or louvered door and the exhaust fan that runs continuously draws conditioned air into the toilet through the grille or in or around the door. If the heat has to get through the walls only not good.

[STEVEusaPA]

Invite the PE over on a cold day...you know, so he can 'splain it to you. (I'd make him sit on the toilet).

[pecmsg]

So here is the scenario: You have two rooms side by side, both concrete block, both have north side exposure, roof exposure, and on slab, not a single lick of insulation. Both rooms have plumbing, and a source of heat. one is heated by an electric unit heater one is heated (and cooled) by a RTU that also feeds other areas. The RTU is removed, because the primary areas it was serving are demolished. NO new source of heat is added to the 1 room to replace what was supplied by RTU.

Their reasoning, "we figured the heat from the next room and the hallway would keep the room warm enough that we wouldnt need to add a new heater".

I swear when someone get the letters PE behind their name, they become very......... ill bit my tongue for fear of retaliation.

How in the heck, does enough heat move through concrete block walls, to keep the room next door from dropping below freezing when its 9* out? Let alone, the room is a bathroom with no heat source. Who the heck wants to go sit on a 40* toilet seat and take a dump?

https://m.youtube.com/watch?v=xPlavncXPKQ

[hvacker]

This is where you test the PE's theory. Offer no opinion, just smile.

[jbhenergy]

This is where you test the PE's theory. Offer no opinion, just smile.

The theory was tested this winter......
They had to put 110v plug in space heaters in the room to keep it warm.

What amazes me, the customer who I would have assumed had a chance to review all plans, was also okay with this. And I guess to top it all off the mechanical contractor on the job didn’t say anything? Or did they but we’re told they were silly maybe?

Do you ever see something really silly and then say wow, I didn’t think people could be so dumb. Then a few weeks latter you find yourself saying it again? I feel I do that more now then I did before.


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[timebuilder]

I see CAS all the time.

[timebuilder]

The first letter is "Crazy".......

[WAYNE3298]

The idea isn't crazy but the application obviously is. Small commercial toilets are conditioned routinely by running the exhaust fan continuously and drawing air into the space usually from the hall. If the hall isn't conditioned and the toilet is walled off from a conditioned space failure is imminent.

[servicefitter]

It will never work without arrows on the floor to show the heat where to go.

[mgenius33]

Oddly enough I’ve had good experiences with engineers for customers. Once I explain what I would like to do with the system, they just tell me to do my thing.

It’s the wanna be engineers that constantly question what you’re doing and how they think it should be done.

[DavidDeBord]

So here is the scenario: You have two rooms side by side, both concrete block, both have north side exposure, roof exposure, and on slab, not a single lick of insulation. Both rooms have plumbing, and a source of heat. one is heated by an electric unit heater one is heated (and cooled) by a RTU that also feeds other areas. The RTU is removed, because the primary areas it was serving are demolished. NO new source of heat is added to the 1 room to replace what was supplied by RTU.

Their reasoning, "we figured the heat from the next room and the hallway would keep the room warm enough that we wouldnt need to add a new heater".

I swear when someone get the letters PE behind their name, they become very......... ill bit my tongue for fear of retaliation.

How in the heck, does enough heat move through concrete block walls, to keep the room next door from dropping below freezing when its 9* out? Let alone, the room is a bathroom with no heat source. Who the heck wants to go sit on a 40* toilet seat and take a dump?

I think part of Calculating the load required for heat, actually included how "fat/ padded" that rear end would be, as well as the heat transmitted from the Load deposited in the toilet, & the heat transmitted from that awesomely sized rear end.

Other than that, whoever came up with not heating the room, was a certified Dumb Azzz.

[DavidDeBord]

It will never work without arrows on the floor to show the heat where to go.

[WAYNE3298]

You guys got the wrong idea. Commercial buildings everywhere have SMALL toilets that do not have conditioned supply air ducted into them. There is no doubt in this case that this design was a miss application. With a properly sized exhaust fan that runs continuously and the surrounding space conditioned the design works very well and the toilet will be negative with respect to the surrounding space. This is not a new idea I have balanced hundreds of these.

[jbhenergy]

You guys got the wrong idea. Commercial buildings everywhere have SMALL toilets that do not have conditioned supply air ducted into them. There is no doubt in this case that this design was a miss application. With a properly sized exhaust fan that runs continuously and the surrounding space conditioned the design works very well and the toilet will be negative with respect to the surrounding space. This is not a new idea I have balanced hundreds of these.

But with an exposed north wall, exposed ceiling load and slab on grade?
Room is probably 12’x12’


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[WAYNE3298]

The design in this case is a misapplication. All I'm saying is there is a difference between an approach that is unworkable and a specific design that is unworkable. What size is the exhaust fan? Was it replaced and does it work? Does it run continuously? I have balanced toilets bigger than this one with no supply that worked just fine. I balanced a men's toilet and a women's toilet in an office building and neither had a supply. The controls contractor decided he could save energy by running the exhaust fans 50% of the time. That turned a good design into a disaster.
In your case the engineer should have known how much conditioned air was needed and either didn't or the exhaust fan isn't running. It sounds like he dropped the ball. There can be issues with the slab having a thermal wick, no or little insulation in the wall or ceiling.

[jbhenergy]

The design in this case is a misapplication. All I'm saying is there is a difference between an approach that is unworkable and a specific design that is unworkable. What size is the exhaust fan? Was it replaced and does it work? Does it run continuously? I have balanced toilets bigger than this one with no supply that worked just fine. I balanced a men's toilet and a women's toilet in an office building and neither had a supply. The controls contractor decided he could save energy by running the exhaust fans 50% of the time. That turned a good design into a disaster.
In your case the engineer should have known how much conditioned air was needed and either didn't or the exhaust fan isn't running. It sounds like he dropped the ball. There can be issues with the slab having a thermal wick, no or little insulation in the wall or ceiling.

Im on board with your thought process 100% in the correct situation. A RR with no/little external loads I can see this working correctly. This application, with exterior wall, ceiling and slab load, not so much. I guess im just amazed at how people that are supposed to be smarter than the average man comes up with this type of stuff on the regular.

[servicefitter]

You guys got the wrong idea. Commercial buildings everywhere have SMALL toilets that do not have conditioned supply air ducted into them. There is no doubt in this case that this design was a miss application. With a properly sized exhaust fan that runs continuously and the surrounding space conditioned the design works very well and the toilet will be negative with respect to the surrounding space. This is not a new idea I have balanced hundreds of these.

Come to St. Louis their are most of commercial buildings with condition air with exhaust fans that cycle with main ahu's and turn on if someone overrides the system. Have a building open 14 to 16 hours a day thats 8 to 12 hours a day x6 days and off 24 Sunday of off time. Thats alot of energy saved per year!

[WAYNE3298]

JB we are in agreement. The best explanation I have came from an old engineer helping me fix a screwed up job. He said "given the proper incentive anyone can f-up a job". I didn't ask him to explain it but it sounded good. That was 35 years ago and it still sounds good.
Service fitter I have been to St Louis. I trouble shot the federal building there and did some balance. They had penthouses with huge fans that wouldn't track each other. The toilet exhaust grilles in that building were so dirty the airflow was about 200 CFM short per grille. It is not that unusual for toilet exhaust to cycle with the AHU'S but any time the building is occupied ASHRAE requires the AHU'S to run and add fresh air.

[servicefitter]

JB we are in agreement. The best explanation I have came from an old engineer helping me fix a screwed up job. He said "given the proper incentive anyone can f-up a job". I didn't ask him to explain it but it sounded good. That was 35 years ago and it still sounds good.
Service fitter I have been to St Louis. I trouble shot the federal building there and did some balance. They had penthouses with huge fans that wouldn't track each other. The toilet exhaust grilles in that building were so dirty the airflow was about 200 CFM short per grille. It is not that unusual for toilet exhaust to cycle with the AHU'S but any time the building is occupied ASHRAE requires the AHU'S to run and add fresh air.

Thinking about what that engineer said if you correlate a job to a football game and the team keeps getting hammered by running the same plays it's going to take a second set of eyes to turn the game around. Experience has taught me one thing if a job is really screwed up it never hurts to have another set of trusted eyes.