What You Need to Know! How to Read and Use the Occupancy Performance Evaluation Criteria (Vertical Vibration)

1. Introduction

In recent years, there has been a growing interest in the habitability and comfort of buildings, and it has become important to ensure occupant performance from the vibrations that occur on a daily basis. The occupant performance required of a building must be agreed upon by the owner, occupants, and designers to set appropriate target performance levels, and the building must satisfy those performance levels.
In order to evaluate occupant performance, evaluation criteria based on the “physical quantity of vibration” are needed, which is in good agreement with “subjective evaluation quantities such as human perception and sensation.
In this issue, we summarize the key points of evaluation of vertical vibration from the “Occupant Performance Evaluation Standard for Building Vibration,” one of the evaluation standards for occupant performance due to vibration, issued by the Architectural Institute of Japan (AIJ).

2. What is occupant performance evaluation?

The “Occupant Performance Guideline for Vibration in Buildings and its Commentary” was published by the Architectural Institute of Japan in 1991 as Japan's first guideline for evaluating daily vibration in buildings (environmental vibration) from the viewpoint of occupant comfort. The occupant performance evaluation is a physical indicator proposed in the guideline to evaluate the occupant performance against vibrations generated in building floors, etc.
The editions were revised in 2004 and 2018, and in the latest third edition, the name was changed from “Guidelines” to “Criteria” as the design elements were separated and the content was focused on the relationship between vibration and the occupants to it.

References: "Occupant Performance Evaluation Criteria for Building Vibration and its Commentary," edited by the Architectural Institute of Japan, 2018.

Thorough Explanation! Occupant Performance Evaluation Criteria for Building Vibration - Vertical Vibration

The Vibration Performance Evaluation Criteria are designed to ensure the performance of a building as an occupant-oriented environment, and are based on environmental vibration (Trivia about Environmental Vibration:Causes of Vibration - A Complete Guide(See Section 3.2.1).

3.1 For steady-state (not widely fluctuating) vibration evaluation

• Evaluated by means of a vertical performance evaluation diagram.
• The vibration to be evaluated is the maximum value of acceleration (0-p, unit cm/s)²)
• Frequencies evaluated from 3 Hz to 30 Hz
• As shown in Figures 2-1 and 2-2, the evaluation curves are different for floors used in residences and for floors used in offices (floors used in residences are rated more severely for vibration than floors used in offices).
• The interval between the evaluation curves is the evaluation level, and the evaluation level is a seven-step evaluation from V-I to V-VII.
• Use the description of the rating levels of vertical vibration in Table 1 to check the correspondence between the degree of concern and discomfort.

Fig. 2-1 Performance evaluation chart for vertical vibration (floor of a dwelling, etc.)

Fig. 2-1 Performance evaluation chart for vertical vibration (floor of a dwelling, etc.)

Table 1.Description of evaluation levels for vertical vibration

3.2 Actual evaluation example Steady-state vibration

Figure 3: Example of vibration occupant performance evaluation

　The actual example is used for evaluation. The acceleration obtained is plotted on the performance evaluation chart, at the evaluation level, and the value with the highest evaluation level is adopted (Figure 3). Acceleration of 3.3 cm/s at 8 Hz²and therefore the evaluation level is V-III. If we check the correspondence between the degree of concern and discomfort in the description of the evaluation level of vertical vibration in Table 1, the result is as shown in Table 2, which is slightly bothersome and not very unpleasant vibration.

Table 1.Description of evaluation levels for vertical vibration

3.1 For steady-state (not widely fluctuating) vibration evaluation

The evaluation of unsteady vertical vibration is performed in the same way as the evaluation of steady-state vibration described in 3.1. However, the maximum acceleration amplitude to be checked against the performance evaluation chart can be reduced according to the method shown in A below.

3.3.1 Acceleration Amplitude Reduction Method

When evaluating unsteady vertical vibrations, the acceleration compared to Figures 2-1 and 2-2 can be reduced according to the duration of the vibration._10msHere, the duration of vibration is defined as the total time that the VL is 55 dB or higher, as described below.
vancomycin-resistant enterococcus_10msis based on the vibration level (VL), which is the vibration acceleration level (VAL) corrected by the whole body vibration sensory characteristics (vertical direction) as defined in JIS C 1510-1995. However, the time constant of VL is originally 630 ms,_10msuses a time constant of 10 ms. The time constant is a numerical value that expresses how quickly the system responds to sudden changes in vibration, and a short time constant is said to capture sudden changes in vibration more easily. Therefore, a time constant as short as 10 ms is used to properly determine the effect of vibration duration. The vibration level of 55 dB is considered to be the value at which one begins to feel shaking.

Figure 4 shows the relationship between A*/A and T.
In addition,_10msis less than 55 dB for 5 s or less, the vibration before and after it is evaluated as one vibration, and the duration before and after it is added.

Figure 4 Relationship between A*/A and T

• A Maximum acceleration amplitude for each band
• A*Acceleration amplitude of each band to be matched with Figure 2-1 and Figure 2-2.
• tVibration duration (s)

3.4Actual evaluation example Unsteady vibration

Let's evaluate this using an actual example. Plot the obtained acceleration on the performance evaluation diagram.
Then, as shown in Figure 5-1, the VL_10msto give the time of the interval above 55 dB. In this case, the time was 0.39 seconds, so the reduction factor is 0.57. Thus, the obtained acceleration 3.3 cm/s²Acceleration 1.88 cm/s multiplied by 0.57²is the non-steady-state performance evaluation (Figure 6). Thus, the occupant performance during the unsteady state is evaluated in V-II.

Figure 5-1._10msHow to calculate the amount of reduction using (Calculate duration from time history waveform)

Figure 5-2 How to derive the amount of reduction using VL10ms (read from the relationship equation between A*/A and T)

Figure 6: Performance evaluation chart for unsteady state reduced by the reduction factor

References: "Occupant Performance Evaluation Criteria for Building Vibration and its Commentary," edited by the Architectural Institute of Japan, 2018.

4. Importance of actual experience

Thus, using the occupant performance evaluation, vibration can be evaluated. Although we can indicate the psychological sensory quantity from the evaluation level, it is difficult to reach a consensus on the evaluation of vibration without actual experience. Therefore, why not visit our showroom to “feel” the performance level of the evaluation criteria?

The vibration simulator will reproduce the shaking of the occupant performance standard. You can also experience the effects of vibration control at the AMD. We look forward to your visit. For details, please contactthis way (direction close to the speaker or towards the speaker)for more information.