VDI 2566 or DIN 4150 as basis for analysis?

Whether reference should be made to VDI 2566 or DIN 4150 as basis for evaluating the transmission of structure-borne sound/oscillations in buildings or not is normally decided in favour of DIN 4150 "Vibrations in buildings."

DIN 4150 contains reference values on what oscillation accelerations may affect people and buildings. According to § 3 Federal Immission Control Act (3), emissions in the meaning of the act are air pollution, noise, vibrations, light, heat, radiation and similar phenomena produced by an installation.

Subject of vibrations

Lifts emit noise and vibrations (structure-borne sound / oscillations) in buildings. DIN 4150 Vibrations in buildings Part 2 "Effects on people in buildings" and Part 3 "Effects on structural systems" deal with the subject of vibrations or "mechanical oscillations of solid bodies with the potential to annoy people or a damage structural systems."

Parts 2 and 3 provide typical values for oscillation speeds [mm/s] in various types of buildings. A distinction is drawn between commercially-used buildings, residential buildings and structures sensitive to vibrations, such as protected buildings.

Structure-borne sound values as test criterion

By contrast, in the current VDI 2566 Sheet 1 and Sheet 2 "Noise protection in lifts" prescribe maximum structure-borne sound levels without reference to the structure or type and usage of the building.

Another difference between DIN 4150 and VDI 2566 is that the structure-borne sound level in VDI 2566 is based more–or-less on "Experience / assumptions" and not on well-founded values identified by measurements.

Another point is that oscillation speeds in DIN 4150 Part 2 and Part 3 in a frequency range of 1 Hz to 100 Hz are referred to as the decisive values to be checked to evaluate the potentially annoying effect on people and buildings. By contrast, structure-borne sound values in the frequency range from 63 Hz to 500 Hz are referred to as test criterion.

Air-borne sound can be disregarded

In the case of lifts with synchronous motors, air-borne sound can as a rule be disregarded; the critical factor is the structure-borne sound or oscillation speed in the low frequency range. The measured noise-insulation of walls at low frequencies is less than at high frequencies, which results in the structure-borne sound / oscillation speed transmitted by a lift being the cause for increased air-borne sound in rooms that require protection.

Measurements based on DIN 4150 can reliably determine whether a lift is actually the "disruptive" noise source or whether the scale of noise insulation in the structure / building or its walls is inadequate or there are sound bridges.

Another advantage of the measurements is the conduct of a check as to whether the limits for effects on people in buildings are being observed. Measurements of the oscillation speed in the lift shaft (shaft pit, shaft wall,, etc.) and in the building (stairway, flat, rooms that require protection, etc.) provide data that is understandable and not based on experience / assumptions.

Recorded with path, speed or acceleration sensors

Vibrations occurring on the structure can be directly recorded with path, speed or acceleration sensors. The evaluation is made on the basis of oscillation speed maximum values. If performance targets from DIN 4150 "Vibrations in buildings" exist, it should be considered whether these values should also be included in VDI 2566.

What good is it to the lift builder / assembly company if a maximum noise level is stated in VDI 2566 Sheet 2 ("Noise protection in lifts without machine-room"), but limits are stated for the maximum permissible oscillation acceleration [mm/s] that may affect people?

Standard impact-sound level cannot always be measured

Excerpt from VDI 2566 Sheet 2:2004-5: No standard impact-sound level can be measured in lifts without machine-rooms, because the bearing forces of the lift are normally transmitted via supporting structures to relatively small niches or consoles on the wall. Since in addition the coupling conditions at the conduction points of the bearing forces are different from lifts with machine-room, the octave band level mentioned-above may be too high.

However, so far no corresponding figures based on experience are available. Consequently, only an approximate estimate can be made on the basis of the construction drawings and construction implementation as to whether the structural noise protection is sufficient.

Measurements based on DIN 4150

If no standard sound-impact level can be measured on "space grounds", measurements based on DIN 4150 are suitable. In Table B.1 of DIN 4150-3, a value of 5 mm/s is stated for short-term vibrations for residential buildings and structures of equivalent design and / or use. There must be a plausibility test regarding the extent to which DIN 52221 ("Building acoustics testing – noise level tests in building technology systems"), DIN 4150 Part 2 and Part 3 and VDI 2566 can be compared with each other.

Structure-borne sound / oscillation speed should be determined with regard to the revision of VDI 2566 to meet the requirements from DIN 52221 and DIN 4150. If measurements that are reliable and understandable are available, the lift builder or assembly company can plan a lift according to the requirements.

Furthermore, when appropriate values exist, which among other things are adapted to the type of the building, it is possible to provide meaningful and effective tenders and coordination between building trades.

Ulrich Nees, Lifts – systems + advice
e-mail: Ulrich.Nees@t-online.de