Attachment 1 - Acoustic Report GSL Church Conditions

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   20. Written certification is required from a suitably qualified person confirming that sound pressure levels
   measured at the nearest residential place comply with the following:
           Air-conditioning

                  7am to 10pm: Maximum level allowable = background + 5dB(A)
                  10pm to 7am: Maximum level allowable = background + 3dB(A)
   21. Noise nuisance beyond the boundary of the site shall not exceed the following levels:
           a. Worship Centre, Offices and Meeting Room

                  7am – 10pm: Background noise level plus 5 dB(A)
                  10pm – Midnight: Background noise level plus 3 dB(A)
                  12pm – 7am: Inaudible
           b. Friendship Terrace

                  7am – 9pm: Background noise level plus 5 dB(A)
                  Hours of use: 7am – 9pm


   NOISE ENVIRONMENT
   The church is part of the Good Shepherd Lutheran School site and the existing church building is mainly used
   for school and church services, church youth group and after school and evening orchestral music. Figure 1
   shows the location of the church building on the school site.
   The nearest residential receptors are located along the school north-eastern boundary. The nearest
   residences along the boundary would presently experience noise from:

          the Childcare Centre children and car park (not part of the school or church);
          people using the existing church and the existing timber deck and stairs;
          the car park adjacent the school/ residential boundary;
          the students and staff using the school buildings and facilities; and
          road traffic on Eumundi Road.




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                                             Figure 1        Site Plan




   NOISE MONITORING
   Ambient noise monitoring was undertaken in May 2018, at Location L1 as shown in Figure 2. The location
   was chosen to be representative of the nearest residential premises along the north-eastern boundary. Noise
   levels at the logger location included student’s voices, people using the church, cars in the car park, birds,
   and road traffic noise from Eumundi Road. The road noise sets the background noise levels.




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                            Figure 2          Locality Plan and Noise Monitoring Location


   The results of the noise monitoring are summarised in Table 1, for a range of parameters.
   Background (BG or LA90) noise data was processed in accordance with the Department of Environment and
   Heritage Protection’s document Planning for Noise Control procedure to determine the Rating Background
   Levels1. Meteorological data from the Bureau of Meteorological Brisbane station was used in the validation
   of the background noise data.




   1 The rating background level is a single figure for each time period that represents the typical minimum LA90 levels

   for day, evening and night time periods. It is the median of the lowest 10th percentile of the LA90 levels.
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   Table 1 Ambient Noise Levels2 dB(A)
        Weekdays +                                                          Leq Log
         weekend              Lmax        L1      L10     L90         Leq     Av           RBL
       Day 7am-6pm             73         63      54       45          53     57            43
      Evening 6-10pm           61         53      47       39          45     46            38
      Night 10pm-7am           56         48      42       35          40     44            30


   NOISE CRITERIA
   Using the measured rating background levels, the conditioned noise criteria can be determined as shown in
   Table 2.
   Table 2 Noise Criteria dB(A)

                                                                Day                Evening                    Night
    Source
                                                          7am – 6pm             6pm – 10pm               10pm – 7pm
    Air Conditioning                                             48                   43                        33

                                                                                      43                   33 (10pm –
    Worship Centre, Offices and Meeting Room                     48
                                                                                                            Midnight)



   The Background + 5dBA or +3dBA approach to setting noise criteria is appropriate for continuous noise such
   as air conditioning plant and noise sources that occur over longer periods of time. It is understood that the
   Friendship Terrace would only be used for shorter periods, infrequently during the week such as morning
   tea after church services. This will reduce the perceived noise level. The duration of the source should be
   considered when setting criteria, as reflected in acoustic research and adopted in documents such as City
   Plan by Brisbane City Council and other councils. This approach averages the noise over the day (11 hours),
   evening (4 hours) and night (9 hours) time periods. Based on observations when monitoring the church
   services and morning tea levels, the morning tea would last for 30 minutes with most people present, and all
   people would leave within 1 hour. Allowing 2 hours for the day time period and 1 hour if used during the
   evening time period the averaged levels would reduce by 7dB(A) day, and 6dB(A) evening. The effect of this
   is shown in the assessment in Table 4, and compared against the Draft Condition criteria.
   Another approach for assessing occasional noise sources is to compare the levels with the existing ambient
   levels. This approach provides that while the noise source is present, the levels are similar to the existing




   2 Noise levels are expressed as a range of parameters. L1, L10, L90 are the “A-weighted” levels experienced for 1%,

   10% and 90% of the time period. Leq is the “A-weighted” level with the same energy as the actual fluctuating noise
   level, and may approximate the average level. The Lmax is the maximum level and is the highest level recorded during
   the time period for an event with the meter set to Fast response time. All values have been averaged over the Day
   (7am – 6pm), Evening (6pm – 10pm) and Night (10pm – 7am) time periods.
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   ambient levels experienced by the residents, thus minimising the noise impact. Table 3 provides noise
   criteria for these assessment methods.
   Table 3 Friendship Terrace Noise Criteria dB(A)

                                                                                Short
                                                                  Day
    Criteria Source                                                            Evening
                                                                7am – 6pm
                                                                              6pm – 9pm
    Criteria - Existing Ambient Leq                                53            46

    Draft Condition Criteria - Friendship Terrace (7am – 9pm)      48            43



   NOISE ASSESSMENT
   The proposed church alterations include the following:

          worship centre;
          offices and amenities;
          covered friendship terrace; and
          meeting room and amenities (lower level).
   The floor plans for the church alterations are shown in Figures 3 and 4.




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                            Figure 3 Ground Floor Plan – Existing and New Alterations




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                     Figure 4 Lower Ground Floor Plan - Existing and New Alterations




   Noise generated by the proposed alterations will include:

          people inside the worship centre;
          people inside the offices;
          people inside the meeting room on the lower ground level;
          people on the friendship terrace; and
          air conditioning plant.


   NOISE ASSESSMENT
   Noise monitoring was undertaken at Good Shepherd Lutheran College in May and August 2018 to confirm
   source noise levels for the activities that are proposed for the new facilities.



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   Worship Centre, Offices and Lower Level Meeting Room
   Noise modelling was undertaken using the measured levels for church services, children playing and office
   noise, to predict levels at the nearest residences. The assessment shows that the noise criteria based on the
   conditions (as shown in Table 2) can be met as follows:
   Worship Centre

          standard constructions for roof, ceiling and external walls;
          acoustic glazing to windows in the Sanctuary, and part of the Eastern wall (closest to the residences);
          air conditioning to enable doors and windows (closest to the residences) to be closed during services.
   Offices and Lower Level Meeting Room

          standard constructions for roof, ceiling and external walls;
          standard glazing;
          air conditioning to enable doors and windows (facing the residences) to be closed during louder
           activities (eg. children playing).
   One of the complaint items referred to noise from chairs being moved on the timber floor of the existing
   building. It is expected that this will relate in part to the setting out of chairs for worship services. The new
   worship centre will have concrete floors (ie. rather than timber) and the seats will be set out permanently
   for services. This will both reduce noise from seats being moved in the new worship centre, and also reduce
   the number of times seats have to be set out in the existing church building.
   The proposed alterations include allowance for the existing church building to be air conditioned. This will
   further reduce noise radiating to the nearest residences by enabling the doors and windows to be closed.
   Air Conditioning Plant
   Plant associated with air conditioning and ventilation for the alterations will be designed to meet the noise
   criteria based on the Draft Conditions (as shown in Table 2), at the nearest residences. The condenser plant
   is planned to be located away from the residential boundary.
   Friendship Terrace
   The friendship terrace will be used for informal gatherings after church services and for other gatherings. It
   is located outside the kitchen to enable people to have morning or afternoon tea. Noise levels from the
   covered friendship terrace have been predicted as shown in Table 4 based on noise levels measured in
   August 2018 for morning teas, and using the approaches as described in the Noise Criteria section of this
   report.




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   Table 4 Friendship Terrace Noise Levels dB(A)



                                Source Noise       Level at Nearest           Day             Short Evening
            Source
                                   Level             Residence            7am – 6pm             6pm – 9pm




    Morning Tea, ~30 people     68dB(A) @ 5m           53dB(A)

                                                                        Ambient criteria      Ambient criteria
                                                                          53dB(A)               46dB(A)

                                60 dB(A) @ 5m          45dB(A)
    Morning Tea, ~16 people




    Morning Tea, ~30 people     68dB(A) @ 5m        46dB(A) Day Av

                                                  47dB(A) Evening Av    Draft Condition       Draft Condition
                                                                        criteria 48dB(A)      criteria 43dB(A)


    Morning Tea, ~16 people     60 dB(A) @ 5m       38dB(A) Day Av

                                                  39dB(A) Evening Av



   From Table 4 it can be seen that for larger groups the noise levels would meet the Day time criteria and
   exceed the Evening criteria by 4-7dB(A). For smaller groups the levels will meet the proposed Day time and
   Evening criteria. Based on the expected infrequent use of the terrace during the evening (eg. currently no
   evening church services), it is expected the occasional evening use would have minimal impact. Limiting the
   hours of use until 9pm further reduces the potential noise impact. To reduce radiation of sound from the
   Friendship Terrace, the following acoustic treatments are proposed:
   Noise Control Measures –

          The ceiling construction will include acoustic absorption panels to reduce the buildup of reverberant
           noise;
          The roof will be raked to reflect sound back towards the church rather than projecting it towards the
           residential boundary.

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   These measures will enable noise impacts from the friendship terrace to be minimised.
   Noise Barriers on the Boundary
   Condition 19 requires a noise barrier to be built on the residential boundary, and references the May 2018
   acoustic report prepared by Acoustics Noise Vibration. The May Report states The existing school/ residential
   boundary fence is presently a paling fence. An acoustic fence could be investigated to confirm if it would provide
   useful attenuation of noise at the nearest residences.
   The effectiveness of a noise barrier has been assessed for the nearest house to the friendship terrace. The
   house is low set and the ground level slopes away along the side of the school buildings. The required noise
   barrier heights to meet the proposed evening criteria for the larger group are as follows:

          Evening criteria (up to 7dB(A) noise reduction)– Top of barrier RL17, Barrier height approximately
           3.4m at the house windows near the centre of the carpark. The barrier would range from
           approximately 2.4m to 4m high along the residential boundary;
          The adjacent house to the nearest house, has a High Set element that would be difficult to shield with
           a noise barrier.
   Having investigated the noise barrier as suggested in the Acoustic Report, this is not considered to be a
   practical solution due to the significant height. Condition 19 should be removed.


   CONCLUSIONS
   It is concluded that:

          noise from the new worship centre, meeting room and offices, and meeting room on the lower level
           can meet the Draft Condition noise criteria at the nearest residences with suitable acoustic
           treatments and air conditioning to enable doors and windows to be closed as required;
          the church alterations will result in a reduction in noise radiating from the existing hall when it is
           used with the air conditioning as this will enable doors and windows to be kept closed;
          the frequency of occurrence of noise from chairs being moved on the timber floor of the existing
           building will be reduced as the new worship centre will have concrete floors (ie. rather than timber)
           and the seats will be set out permanently for services;
          air conditioning plant will be located away from the residential boundary and selection of suitable
           plant can enable the Conditioned criteria to be met;
          noise from the friendship terrace will be infrequent and of relatively short duration and it is
           considered that the Conditioned criteria are overly onerous. Assessment against more appropriate
           criteria indicate levels from larger groups can meet the day time criteria, and it is expected that the
           occasional evening use with the time limited to 9pm would have minimal impact. Noise from Smaller
           groups would meet the day and evening criteria;
          Noise predictions show that use of a noise barrier on the boundary to address Friendship Terrace
           noise is not practical due to the terrain and the significant height that would be required to achieve
           a suitable noise reduction;

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          Acoustic treatments can be applied to the Friendship Terrace to minimise noise radiating towards
           the residences.
   It is concluded that noise from the church alterations will result in a reduction in noise from inside the church
   as the new building will be air conditioned to enable doors and windows to be kept closed. Air conditioning
   plant can be designed to meet the Draft Condition criteria. Noise from the friendship terrace will be
   infrequent and of relatively short duration, and can be managed to minimise noise impacts.


   RECOMMENDATIONS
   It is recommended that:

          the measures to control noise from the new Worship Centre, Office and Lower Meeting Room
           facilities described in this report be developed during detailed design stage and incorporated into
           the building alterations to meet the Draft Condition criteria;
          mechanical plant be selected and designed to meet the Draft Condition criteria;
          acoustic treatments described in this report be applied to the Friendship Terrace to minimise noise
           radiating to residences;
          Draft Condition 19 be deleted, as a noise barrier is not a practical solution for noise radiating from
           the alterations;
          Draft Condition 21b be deleted and a new clause be added to Condition 13, limiting the friendship
           terrace use to suitable hours such as 7am – 9pm.


   Yours sincerely,
   Acoustics Noise Vibration




   David Borgeaud
   Principal Acoustics Engineer




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