Elevator noise and other disturbances from the ceiling (live on the top floor)

[gos84]

Cool program, I must say! Does this program also calculate on structure-borne sound as I assume the effect of the wall would be different if it's airborne or not? But as I understand it, the difference is very small for low frequencies? The impact sound isn't the brake that previously sounded like a hammer at about 45 dB. Now it's relatively dark, but doesn't seem like under 100Hz (hard to say without equipment and experience). But if it's around 200Hz, then a properly constructed wall should help?

I also think, like you said, that the key is vibration absorbers. On the thing that makes the impact sound, there are hard very small pads of hard black plastic (like furniture pads). I thought maybe larger rubber pieces would work. Maybe one large rubber rectangle that distributes the vibrations?

This particular program doesn't calculate structure-borne sound. But structure-borne sound becomes airborne sound before you hear it in the room, and the new wall will create a resonance frequency in the cavity. (the new cavity becomes a spring and the gypsum a mass in a mass-spring system) So the image is mostly to illustrate just that. Now, I do think the effect of the resonance in the calculation program is a bit overestimated.
But one should be a bit careful and not assume it's always better to add another wall even if it's freestanding.
If the pads serve their purpose, an expert should take a look. ChristianBerner makes good products and designs themselves, but there are of course several others.

 

[markaner]

This program does not account for structure-borne noise. But structure-borne noise becomes airborne noise before you hear it in the room, and the new wall will create a resonance frequency in the cavity. (the new cavity becomes a spring and the gypsum becomes a mass in a mass-spring system). So the image is mainly to illustrate just that. Now, I think that the effect of the resonance in the calculation program is slightly overestimated. But you have to be a little cautious and not always think that it's better to add another wall even if it's freestanding. If the supports fulfill their purpose, an expert should take a look as mentioned. ChristianBerner makes good stuff and dimensions themselves, but there are of course several others.

Okay, I understand! The results have come in now from yesterday's measurement, 42 dB. This is from measuring in the same place as before which gave 32 dB. However, I don't hear any difference in noise level and therefore suspect that the 32 dB measurement was inaccurate. So the saga continues, so to speak. Further, the acoustics consultant will consult with Schindler and try to find solutions that can be made in the elevator shaft as I understood it. On the other hand, I am faced with the dilemma of whether I want them to complete the wall now or if I want to tear it down and get back the 9x550cm that the wall has taken up. This is all free of charge for me, but the construction manager says that "maybe it can help in the end anyway." What would you have done? I maybe think it has improved a bit actually, even though the tests show a 10 dB increase. The difference is very small in any case.

 

[gos84]

Okay, I understand! The result from yesterday's measurement has now come in, 42 dB. This at the same measurement location as before showed 32 dB. However, I don't hear any difference in sound level and therefore suspect that the 32 dB measurement was not accurate at all. So the saga continues, in other words. Furthermore, the sound consultant will consult with Schindler and try to find solutions in the elevator shaft as I understood it. On the other hand, I am faced with the dilemma of whether I want them to complete the wall now or if I want to tear it down and regain the 9x550cm that the wall has taken up. This is, of course, at no cost to me, but the construction manager suggests that "it might help in the end anyway." What would you have done? I perhaps think it has actually improved a bit despite the tests showing an increase of 10 dB. The difference is very small nonetheless.

I don't dare to answer that. The wall will be better overall. And freestanding walls are usually built against lifts. It's just if the frequency of the problem noise happens to coincide with the resonance frequency of the new double wall that it would have been unnecessary.
Then I don't know how much of the structure-borne noise is going other ways. If they manage to eliminate the structure-borne noise, then the new wall will be good. Whether the potential benefit is worth 0.5 sqm... that I don't know

 

[markaner]

I dare not answer that. The wall improves overall. And standalone walls are usually built against the elevator. It's if the frequency of the problem noise happens to coincide with the resonance frequency of the new double wall that it would have been unnecessary.
Then I don't know how much of the structure-borne sound goes other ways. If they get rid of the structure-borne sound, the new wall will be good. Whether the potential benefit is worth 0.5sqm... I don't know

I understand, it really becomes a very subjective assessment! The strange thing is that I don't hear any difference at all now, so I don't know if it will ever be able to have an impact. And if it doesn't even help in the slightest in the end, then there's no point in keeping it. The apartment is 45 sqm, so every little bit of space is valuable to me, and the acoustician had said that it might as well be torn down after seeing the result. But I haven't spoken with him personally and he's obviously been wrong before. I'll need to give it a good think, I suppose!

 

[Isakare]

Was involved in building a sound-insulating wall between a gym and a stairwell. 3 floors/2 apartments per floor, the gym was on the ground floor.

It was built similarly to yours, but with one difference. The insulation was 30 mm that hung in the cavities, there are special adhesive holders for hanging insulation. The acoustician's explanation was that it should be air-insulation-air.
The wall also received 3 layers of gypsum.
Before, all 6 apartments in the stairwell complained about noise and music from the gym; afterward, it was only the tenant on the 2nd floor right across who heard anything (the tenant on the 1st floor was deaf).

 

[gos84]

I understand, it becomes a very subjective assessment! The strange thing is that I don't hear any difference at all now, so I don't know if it will ever be able to have an impact. And if it doesn't even help in the slightest in the end, then there's no point in keeping it. The apartment is 45 sqm, so every little bit of space is valuable to me, and the acoustician had said it might as well be torn down after seeing the results. But I haven't spoken to him personally, and he has obviously been wrong before. I'll just have to give it a good think!

One could summarize it as the wall didn't help for the noise that is most audible now. But let's say if they managed to eliminate that noise at the source now. Then it could be that another noise becomes the loudest then. Since it is quiet in your apartment otherwise, you might be bothered by that. And maybe your new wall is good against that noise.
Who knows.

 

[nomoD2]

You're not far off! The report showed that 80HZ was at 44 when the limit is 40 on one occasion, I know. But generally, frequencies 63-100Hz seem to be the worst. However, only 80hz has been above the limit.

But how can you isolate the impact sound, do you think? Apparently, there's some thing that turns on and off in the elevator that's on my wall and sounds 40dB in my apartment. Have they messed up with my additional wall or is it just about trying to dampen more inside the elevator shaft? Thinking if the 10mm air gap can be way too short for such low frequencies?

Hard to say much more without seeing some third-octave band measurement data.
But if I wildly guess:
The elevator motor causes structural noise in the apartment-separating wall due to one/some of the following reasons: wrong damper/weak steel frame/too few insertions in the wall. The noise in the apartment is dominated by sound in the 63Hz third-octave band, the new wall made the total construction worse (1-2dB) for sound insulation in just 63Hz (better for all higher frequencies) and the sound level in the apartment becomes about the same.
Lekv,dBA meets the requirements, Lekv,dBC and LAFmax barely meet the requirements, but the Public Health Agency's guidelines for low-frequency noise indoors are not met, but this is not reported since it is not stated as a requirement in BBR as long as Lekv,dBC is approved.
I could, of course, be completely wrong, I just wanted to guess a bit
(Now ignoring the impact sound because they should be able to isolate that away)

Based on experience from conducting sound level measurements on a large number of elevators over the years as a professional acoustician, the peak levels usually stem from the following parts/events:

1) Doors opening and closing
2) Frequency converter changing operating mode
3) Elevator brake releasing and locking
4) Impact sounds caused by lateral cage movements

The equivalent level, which is the average sound level during the time an acoustic event occurs, will obviously be higher if the elevator installation emits high sound levels when the elevator car is passing several floors. In some cases, the sound level decreases the further the car is from the measurement room.

In cases where there are problems with structural noise from the motor itself, however, the sound level in the room where the measurement is conducted does not decrease much despite the car moving further away from this room.

When reporting LAeq and LAFmax in (dB) as well as unweighted sound levels at low frequencies (31.5-200 Hz), these results refer to a well-defined operational cycle in Swedish Standards where the elevator is operated from floor to floor and all the way up and down.

LAeq and LAFmax for travel between individual floors are rarely reported except in cases where one wants to demonstrate to the client that it is precisely between individual floors that the elevator installation likely needs further adjustment.

 

[nomoD2]

Cool program, I must say! Does this program account for structure-borne sound too, as I assume the effect of the wall differ if it's airborne or not? But as I understand, the difference is very small for low frequencies? The impact sound is not the brake that previously sounded like a hammer at about 45 dB. Now it's relatively muted, but it doesn't feel like it's under 100Hz (hard to say, of course, without equipment and experience). But if it's around 200Hz, a properly constructed wall should help?

However, I also believe, as you said, that the key is vibration absorbers. The object making the impact sound has very small pads of hard black plastic (like furniture pads). I thought one should have larger rubber pieces, perhaps a single large rubber rectangle to distribute the vibrations?

The wall is probably okay. I'll throw in a small image below to show what I mean could be a problem:
[image]
To not get a deterioration in low frequency, you need to increase the extension quite a bit. But the problem is probably that they need to better isolate the source of the sounds. Unfortunately, it's not my area. But those who supply the vibration isolators help calculate what needs to be done. It depends, as I understand it, on the weight of what's vibrating and the frequency that needs dampening. It’s the same principle for both the motor and the device causing the impact sound.
Then another guess I have for elevators is that the cushion on which the motor rests is dimensioned for the elevator's maximum load, which never happens and then might be too hard.

Gos84, are you an acoustician? I see you've calculated in the software Insul. At the bottom left in the image, you see it says 42 Hz. That is the cavity resonance achieved when the additional insulating wall is added to the existing concrete wall.

The purpose of the mineral wool in this additional insulation is to damp this resonance.

If the distance between the inside of the gypsum and the concrete wall is increased, this resonance frequency is shifted downwards, and the reverse happens if the distance is decreased.

It might very well be that the dull impact sound is still the brakes. After the wall is additionally insulated, you can see from the image that the improvement in airborne sound insulation increases with frequency. The previously more high-frequency impact sound may then be perceived as significantly duller in character because its spectrum in your apartment now contains significantly less high-frequency tone components and more or less unchanged low-frequency tone components.

 

[gos84]

Gos84, are you an acoustician?

That's right, though I'm not very knowledgeable about elevators. I always state that the elevator supplier is responsible for ensuring that the elevator meets the requirements with the chosen frame. Usually, if there are issues, they tend to be resolved after adjustments.
However, I got the impression that the motor might also be the culprit in this case. But that typically happens if it had been a thinner concrete wall. 1cm air gap and 45 studs seemed a bit narrow to me?

 

[markaner]

Just want to say that I am very grateful for all the tips, help, and answers I receive. Thank you very much!

UPDATE: Today a technician from Schindler was here to fix the frequency converter which has been the loudest (42dB). He bought a regular rubber block from the store and attached it between the wall and the frequency converter. This has actually lowered the noise level from 42dB to maybe around 34dB (measured with a phone). However, I would have preferred if they bought something specifically designed for the purpose. Surely, it should provide a significantly better result for relatively little money?

Anyway, it's nice to have an improvement after much effort. But now the worst noise is coming from the elevator car's brake when it releases and locks, as nomoD2 mentioned. This seems to sound around 35dB, and the technician says they can't isolate it from vibrations because it needs to be firmly fixed, as I understood it. So he seems to mean that there’s nothing he can do about it. Do you have any thoughts on this and what can be done? It’s also strange that this sound feels much more high-pitched than the other noises, yet it hasn't improved with the isolation.

I can also add that they have reduced the elevator's speed because it hums all the time when it operates. This has helped, but now the elevator is probably down to about 60% of standard speed. Is this noise from the guide rails and occurs as the elevator moves, or is it the motor, do you think? And could it be vibration-isolated in that case? I believe the equivalent noise level is about 24-26dB. So even there, the noise level is just on the border of acceptable.

 

[clabbe]

Just want to say that I am very grateful for all the tips, help, and answers I receive. Big thanks!

UPDATE: Today, a technician from Schindler was here to fix the frequency converter that has been making the most noise (42dB). He had bought some regular rubber block from the store that he attached between the wall and the frequency converter. This has actually reduced the noise level from 42dB to maybe around 34dB (measured with the phone). However, I would have preferred they bought something specifically designed for this purpose. Surely that would give a notably better result for relatively little money?

Anyway, it's nice to have an improvement after much toing and froing. But now, the worst noise comes from the elevator cage brake when it releases and locks, as nomoD2 wrote about. This seems to sound around 35dB, and the technician claims they can't vibrationally isolate it since it has to be mounted rigidly, as I understood it. So he seems to think there's nothing he can do about it. Do you have any thoughts on this and what can be done? It's also strange that this noise feels significantly more high-pitched than the other sounds but hasn't improved with the isolation.

I can add that they have also reduced the speed of the elevator because it hums continuously when in operation. This has helped, but now the elevator is surely running at 60% of standard speed. Is this noise from the guide rails and arises when the elevator moves, or is it the motor, do you think? And could it be vibrationally isolated in that case? I believe the equivalent noise level is about 24-26dB. So even there, the noise level is just on the verge of being acceptable.

As I wrote in post #15, it is possible to adjust the stroke of the brakes, at least on the brand I have worked with for over 40 years. I doubt it wouldn't be possible on a Schindler elevator. Reducing the speed is just a temporary solution, not a permanent one. There are many parameters to adjust in frequency control to achieve quiet operation, and if the technician on site can't do this, they should contact their technical support, who should be able to tell them what needs adjustment.
I come back to the question of how the elevators sound in the other stairwells; have any comparative measurements been performed in corresponding apartments?
/Regards Claes

 

[markaner]

As I wrote in post #15, it's possible to adjust the brake stroke, at least on the brand I've worked with for over 40 years. I doubt it wouldn't be possible on a Schindler elevator. Lowering the speed is just a temporary solution, not a permanent one. There are plenty of parameters to adjust in frequency control to achieve quiet operation; if the technician on-site can't manage this, they have technical support to turn to for advice on what should be adjusted. I return to the question of how the elevators sound in other stairwells; have any comparative measurements been taken in equivalent apartments? Regards, Claes

You're probably right in what you're saying. I know an acoustician, construction company, a representative from Schindler, and someone else are supposed to have a meeting next week about what they can do. Lowering the speed seems to be considered a permanent solution, although one might think they should address the noise instead.

From what I understand, there's another apartment where someone complained about the elevator noise. This one was also at the top. They adjusted the elevator until it met the requirements and then closed the case. How it sounds now, I don't know other than the person accepted the test and seems to have stopped complaining. Clearly, it sounds unusually loud in my apartment.

 

[nomoD2]

You are certainly right in what you say. I know that acousticians, construction companies, a representative from Schindler, and someone else are supposed to have a meeting next week about what they can do. Lowering the speed seems to be considered a permanent solution even though one might think they should address the noise instead.

From what I understand, there is another apartment where they have complained about the elevator noise. This one was also at the top. There they have adjusted the elevator until it met the requirements and then closed the case. How it sounds now, I do not know other than that the person accepted the test and seems to have stopped complaining. It is clear, however, that it sounds unusually loud in my apartment.

The additional insulation built in your apartment improves airborne noise insulation and can somewhat dampen the sound that would have radiated from the existing concrete wall to which the building's guide rails and motor are anchored.

To address the noise disturbance you are experiencing, it is not sufficient to just construct additional insulation as has now been done in your apartment. When noise disturbances arise from elevators, structure-borne noise is often the problem.

The following parts should be considered when thinking about which measures should be undertaken:

• Priority 1 should always be to isolate the elevator motor's vibrations
• Ensure good linearity of the guide rails along which the elevator car runs
• Ensure that the steering wheel bearings are well lubricated
  
• Ensure that the elevator car brakes move as smoothly as possible
• Ensure that the track in which the elevator door runs is kept clean, as gravel in this part can create unpleasant scraping sounds.

Good luck!

 

[norrbottenssnickaren]

The additional insulation installed in your apartment improves airborne sound insulation and can somewhat reduce the sound that would have radiated from the existing concrete wall to which the building’s guides and motor are anchored.

To address the noise disturbance you are experiencing, it is not enough to only build additional insulation as has now been done in your apartment. When noise disturbances arise from elevators, it is often structural noise that is the problem.

The following aspects should be considered when considering what actions should be taken:

• Priority 1 should always be to vibration isolate the elevator motor
• ensure good linearity of the guides along which the elevator car runs
• ensure that the bearings of the guide wheels are well lubricated
  
• ensure that the elevator car brakes move as smoothly as possible
• Ensure that the track in which the elevator door runs is kept clean, as gravel in this part can create unpleasant scraping noises.

Good luck!

doubtful if there is a roller system on the elevator. Don’t think so… it’s rare nowadays.

Since the motor is most likely firmly mounted to the guide or shaft wall, it is practically impossible to isolate it. It cannot be detached from the installation in that way.

The parking brake's action can be somewhat adjusted But they tend to be quite noisy regardless :/

machine room-less elevator… would personally not want to live wall-to-wall with that elevator motor.

If the shaft doors are uninsulated, the sound can of course travel significantly far :/

by the way, I don't know why you're giving those tips to the op. Don't think you're an elevator technician first and foremost and what do you think the op is going to do with the info you provide?

 

[nomoD2]

I have 12 years of experience as a professional acoustician and have conducted control measurements on at least 100 elevators. What professional experience do you have that gives you the authority to dismiss my suggestions?