Attachment 1 - Acoustic Report GSL Church Conditions

   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.
Acoustics Noise Vibration                                    5                               0145 GSL Church Conditions Rpt 02