Generator Installation - Summerset Cambridge Electrical Acoustic - Waipa District Council
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Generator Installation Summerset Cambridge Electrical Acoustic Job Ref: 191007 Date: 30 July 2021 Issue: E
Issue Authorisation
ISSUE DESCRIPTION DATE
A Review 12 Aug 2020
B Revision – Permanent Generator only 24 Aug 2020
C Revision – Stack Location Updated 19 Nov 2020
D Revised Masterplan 21 Jul 2021
Written By: Liam Membery Reviewed By: James Glen
Discipline: Mechanical Discipline: Acoustics
Liam Membery James Glen
BE (Hons) BEng (Hons), AMIOA, MASNZ
Mechanical Engineer Senior Acoustic Engineer
This report is subject to Powell Fenwick Conditions of Engagement which among other conditions prohibits the on sale of the report, its
use outside this project, and duplication in part only of the report.
The report has been prepared solely for the benefit of our client. No liability is accepted by this firm or by any principal, or director,
or any servant or agent of this firm, in respect of its use by any other person. Any other person who relies upon any matter contained
in this report does so entirely at their own risk.
Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm i
Table of Contents Introduction ............................................................................. 1 1. Essential services ............................................................................. 1 2. Permanent Generator ........................................................................ 1 2.1 Emissions to the atmosphere ................................................................. 1 2.2 Fuel .............................................................................................. 3 2.2.1 Assessment ..................................................................................................... 3 2.3 Acoustic ......................................................................................... 4 2.3.1 Criteria .......................................................................................................... 4 2.4 Assessment ...................................................................................... 5 3. Compliance ..................................................................................... 6 3.1 Permanent Generator ......................................................................... 6 Appendix A............................................................................... 7 Appendix B .............................................................................. 11 Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm ii
Introduction
This report contains details on consent requirements for the proposed provision of an emergency
generator supply for limited essential services in the Main Building.
1. Essential services
The essential services have been advised by Summerset as:
Emergency HUB
Full lighting in care lounge and dining Level 1
Safe passage lighting in stairwells and egress routes
Power to drugs room fridge
One chiller fridge/freezer to remain operational with five additional power points in
commercial kitchen
Max eight power points in satellite kitchen in the Care Centre
Care lounge and dining Level 1; eight power points max
Power to the access control in the dementia wing; and
Central lift in Main Building and any lift in the 3 storey apartment blocks separate to the Main
Building.
The preliminary assessment of the load is 90kVA.
2. Permanent Generator
The preliminary assessment of the essential load would require a 150kVA generator to safely allow a
margin for any fluctuations in load.
The generator should be housed in a weatherproof canopy.
150 kVA is a standard capacity and readily available.
The generator will be permanently connected to the building main switchboard and would be operated
by an auto mains fail controller.
2.1 Emissions to the atmosphere
The requirements for air discharge are governed by the Waipa District Council district plan and by the
Waikato regional plan.
It is proposed the generator would be located to the west of the Main Building and south of the
bowling green, seen in Figure A2 of Appendix A.
Waipa District Council classifies the generator enclosure and exhaust stack as a building under their
district plan. However, under ‘Schedule 1, Part 1, Clause 4 – Unoccupied detached buildings’ of the NZ
Building Code, the generator enclosure and generator meet condition 1(a) but do not meet condition 2
being located a minimum of 10m from the Main Building with its own height a maximum of 8m.
Therefore providing the enclosure meets all other relevant conditions of Schedule 1 of the Building
Code, the enclosure does not require building consent
Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 1
The Waikato Regional Council regional plan requires the chimney height to be 3 metres above the highest point of any roof within 20 metres under condition e) of Section 6.1.12.1 Permitted Activity Rule – Combustion of Fuel for Heat Release. Figure A3 in Appendix A shows the required stack height based on the location of the chimney. As per the master plan drawing dated 28 Jul 2021, the generator flue is to be located a minimum of 20 metres from the Main Building (Figure A4, Appendix A). Hence, the chimney height must be at least 3 metres above the highest point of the roof of the nearby villas, which are typically 4 metres tall and the stack will provisionally be set at 7.5 m tall. The final height of the stack will be confirmed during the detailed design stage of the project and will take into account the height of the roof of the nearby villas and any ground level disparity between the villas and the generator enclosure. Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 2
2.2 Fuel The diesel fuel tank will be less than 500 litres. The engine will burn about 34 litres per hour at full load. The integral tank would provide about 11 hours run time at full load. It could be expected with varying load that the fuel might last for 24 hours in an operational situation. It is not deemed necessary to provide a separate bulk tank. The use of hazardous substances is controlled under the Health and Safety at Work (Hazardous Substances) Regulations 2017. A 500 litre tank located in an open outdoor enclosure has no special regulations but must conform to the generic controls listed below. 2.2.1 Assessment The generator will be equipped with an integral bunded tank in order to comply with the likely requirements of a controlled fuel storage activity. Any transfer points between the integral tank and the generators engine will also require containment. There is a need to prevent any diesel spillage from entering the storm water system. Hence, a sump cover or shut off valves are proposed to be held/installed on site. Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 3
2.3 Acoustic
2.3.1 Criteria
The Waipa District Plan is a key document for the district. It contains policy guidance and rules on
development and subdivision and also seeks to protect important buildings, landscapes and natural
areas.
The proposed area for Summerset Cambridge is zoned as Residential in the Waipa District Plan. The
East and South bordering sites are also Residential. The surrounding area to the North is zoned as
Deferred Residential. The strip along the West bordering the site is zoned as a Deferred Reserve zone.
See Figure A1 in Appendix A for the site location and surrounding zones.
Under Definitions, a temporary diesel generator is defined as:
‘Temporary diesel generators’ means the use of diesel fired generators during the duration of
a natural disaster and or during outages of electricity supply.
This definition includes a permanently installed generator used during emergency situations as the use is
considered temporary.
Below is the applicable District Plan noise rule from the Waipa District Plan Section 2.4.2.25 for
Residential zones:
‘Rule - Noise
2.4.2.25 Activities shall be conducted and buildings located, designed and used to ensure that they do not
exceed the following noise limits at the boundary of the site:
(a) Monday to Saturday - 7.00am to 10.00pm 50dBA (Leq)
(b) Sundays & Public Holidays - 8.00am to 6.00pm 40dBA (Leq)
(c) Sundays and Public Holidays - 8.00am to 8.00pm 40dBA (Leq)
in Character Area 4 in the Cambridge Park Residential Zone
(d) At all other times 40dBA (Leq)
(e) Night time 10.00pm to 7.00am single noise event 70dBA (Lmax)
Provided that this rule shall not apply to the use or testing of station and vehicle sirens or alarms
used by emergency services.
All noise levels shall be measured and assessed in accordance with the requirements of NZS
6801:2008 – Acoustics – Environmental Sound and assessed in accordance with NZS 6802:2008 –
Acoustics - Environmental Noise.
Activities that fail to comply with this rule will require a resource consent for a discretionary
activity.’
At the adjacent Residential and Deferred Residential boundaries the noise levels of the generator will
need to meet 50 dB LAeq from Monday to Saturday between 7:00 am and 10:00 pm. During night times
and all day Sundays and public holidays, the noise level is to be 40 dB LAeq.
Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 4
Below is the applicable noise rule for the Reserve Zone to the west as per District Plan Rule 5.4.2.15:
‘Rule - Noise
5.4.2.15 Activities and/or events shall be conducted, and buildings located, designed and used to ensure
that noise levels do not exceed the following limits at the site boundary where a reserve adjoins
the Residential Zone or the notional boundary of any dwelling in any other adjoining zone:
(a) Monday to Saturday - 7.00am to 10.00pm 55dBA (Leq)
(b) Sunday and Public Holidays - 8.00am to 8.00pm 50dBA (Leq)
(c) At all other times 40dBA (Leq)
(d) No single noise event between 10.00pm to 7.00am 70dBA (Lmax)
shall exceed the following
The noise levels shall be measured and assessed in accordance with the requirements of NZS
6801:2008 – Acoustics – Environmental Sound and assessed in accordance with NZS 6802:2008 –
Acoustics – Environmental Noise.
Activities that fail to comply with this rule will require a resource consent for a discretionary
activity.’
Section 17 Works and Utilities states the use of diesel generators in Residential Zones is classified as a
discretionary activity. Section 17.4.1.6 is stated below:
17.4.1.6 Activity: Power generation Residential Zone and
Large Lot Residential
Zone
(f) Temporary Diesel generators Discretionary
provided that the setback rules in
the relevant zone are met.
There is no exemption for the emergency use of generators within the District Plan. As the emergency
use of the generator could occur during the night, we will design to the night time noise limits in
2.4.2.25 and 5.4.2.15 of 40 dB LAeq at the surrounding boundaries.
2.4 Assessment
The noise from the permanent generator has been modelled using SoundPLAN, a proprietary noise
modelling software which implements the principles of ISO 9613-2 for outdoor noise propagation.
Generator selections have been provided by the Electrical Engineer, as detailed in Section 2 of this
report.
The proposed location of the generator is seen in Figure A2 of Appendix A. The noise contour plots for
operation of this generator over the ground and first floors are presented in Figures B1 and B2 of
Appendix B with no acoustic screening.
The generator noise is less than 40 dB LAeq at all boundaries, the 150 kVA canopy set is compliant with
the District Plan ‘at all other times’ night time noise limit of 40 dB LAeq at all adjacent boundaries.
Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 53. Compliance The rules for noise, fuel storage and emissions have been advised above. Noise contours are provided to present a graphical representation of the noise effects across site. 3.1 Permanent Generator It is recommended that the permanent generator is installed in a fully compliant manner as a minimum. Waikato Regional Council has a minimum chimney stack height based on the proximity of the stack to other buildings. If the chimney is erected 20 metres from the Main Building as shown in Figure A4 of Appendix A, then the stack height will be required to be 3 metres above the ridgeline of the nearby villas (i.e. approximately 7.5 metres tall). The fuel storage within the generator is compliant with the District plan as long as the generic control under Health and Safety at Work (Hazardous Substances) Regulations 2017 are met. It is advised that the facility be able to be shut off from the local storm system via a sump cover or shut off valves to prevent diesel spillage entering the storm water system. The generator is compliant with the District Plan noise limits. Screening may be required protect the on-site occupants from the effects of the generator during routine testing. Testing is to be carried out during day time hours. Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 6
Appendix A
Figure A1: Site Location highlighted in red and Zoning
Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 7Figure A2: Summerset Cambridge Plan & Generator Location Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 8
Figure A3: Summerset Cambridge required stack height based on chimney stack location. A chimney stack located in red region requires a 16 metre stack height,
In the blue region requires a 13 metre stack height, and in the green region requires a 7.5 metre stack height.
Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 9Figure A4: Summerset Cambridge stack location corresponding to a 7.5 metre stack height. Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 10
Appendix B
Figure B1: Ground floor noise contour plot of 150 kVA generator with no screening. Red contour is night time noise limit of 40 dB LAeq
Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 11Figure B2: First floor noise contour plot of 150 kVA generator with no screening. Red contour is night time noise limit of 40 dB LAeq Powell Fenwick | 191007 Report Generators Issue E 30 Jul 2021 lgm 12
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