Infrastructure Due Diligence Report

Infrastructure Due Diligence Report

11 Gibbons Street, Redfern 11 Gibbons Street, Redfern NSW 2016

PREPARED FOR PREPARED BY

St. George Community Housing Northrop Consulting Engineers

Level 5, 38 Humphreys Lane, Level 11, 345 George Street

Hurstville NSW 2220 Sydney NSW 2000

Tel: 02 9001 2220 Tel: 02 9241 4188

Ref: SY180648-MDR01

Rev: 3

Date: 26.04.2018

REPORT

SY180648: 11 Gibbons Street, Redfern Infrastructure Due Diligence Report | Rev 3 | 26.04.2018 Page 1

INFRASTRUCTURE DUE DILIGENCE REPORT

Activity Schedule

Date Revision Issue Prepared By Approved By

22.03.2018 1 Draft for Review S.Murray & R.Nair G.Lukic & S.Parajuli

03.04.2018 2 For Review S.Murray & R.Nair G.Lukic & S.Parajuli

26.04.2018 3 For Review Murray & R.Nair & S.Parajuli

Northrop Consulting Engineers Pty Ltd

ACN 064 775 088 | ABN 81 094 433 100

Level 11, 345 George Street, Sydney NSW 2000

02 9241 4188 | [email protected] | www.northrop.com.au

© 2018 Northrop Consulting Engineers Pty Ltd. All rights reserved.

This document has been prepared on behalf of and for the exclusive use of St. George Community Housing, and is subject to and issued in

accordance with the agreement between St. George Community Housing and Northrop Consulting Engineers. Northrop Consulting Engineers

accepts no liability or responsibility whatsoever for it in respect of any use of or reliance upon this document by any third party. Copying this

document without the permission of St. George Community Housing or Northrop Consulting Engineers is not permitted.


TABLE OF CONTENTS

1. Introduction ......................................................................................................................................................... 4

1.1 General ....................................................................................................................................................... 4

1.2 Limitations and Exclusions ......................................................................................................................... 4

2. Hydraulic Infrastructure ....................................................................................................................................... 6

2.1 Sydney Water Sewer Infrastructure ........................................................................................................... 6

2.2 Sydney Water Potable Water Infrastructure .............................................................................................. 7

2.3 Jemena Natural Gas Infrastructure ............................................................................................................ 9

2.4 High Voltage Infrastructure ........................................................................................................................ 9

2.5 Low Voltage & Street Light Infrastructure ................................................................................................ 10

2.6 Communications ....................................................................................................................................... 12

3. Budget Estimate ................................................................................................................................................ 13

3.1 High-Level Budget Estimate ..................................................................................................................... 13

4. Appendix A – Sydney Water Infrastructure ....................................................................................................... 16

5. Appendix B – Jemena Natural Gas Infrastructure ............................................................................................ 17

6. Appendix C – Maximum Demand Calculation .................................................................................................. 18

7. Appendix D – Statement of Availbale Pressure and Flow ................................................................................ 19

FIGURES

Figure 1 – Site Location Plan ..................................................................................................................................... 4

Figure 2 – Existing Electrical Infrastructure ............................................................................................................. 10

Figure 3 – View from the Front of the Property ........................................................................................................ 11

1. Introduction ......................................................................................................................................................... 4

1.1 General ....................................................................................................................................................... 4

1.2 Limitations and Exclusions ......................................................................................................................... 4

2. Hydraulic Infrastructure ....................................................................................................................................... 6

2.1 Sydney Water Sewer Infrastructure ........................................................................................................... 6

2.2 Sydney Water Potable Water Infrastructure .............................................................................................. 7

2.3 Jemena Natural Gas Infrastructure ............................................................................................................ 9

2.4 High Voltage Infrastructure ........................................................................................................................ 9

2.5 Low Voltage & Street Light Infrastructure ................................................................................................ 10

2.6 Communications ....................................................................................................................................... 12

3. Budget Estimate ................................................................................................................................................ 13

3.1 High-Level Budget Estimate ..................................................................................................................... 13

4. Appendix A – Sydney Water Infrastructure ....................................................................................................... 16


5. Appendix B – Jemena Natural Gas Infrastructure ............................................................................................ 17

6. Appendix C – Maximum Demand Calculation .................................................................................................. 18

7. Appendix D – Statement of Availbale Pressure and Flow ................................................................................ 19

TABLES

Table 1 – Sewerage Generation Estimate ................................................................................................................. 6

Table 2 – EP Capacity Limitations for Reticulation Sewers ....................................................................................... 6

Table 3 – Potable Water Demand Estimate ............................................................................................................... 7

Table 4 – Fire Hydrant Service Demand .................................................................................................................... 7

Table 5 – Fire Services Water Storage Tank Sizing .................................................................................................. 9


1. INTRODUCTION

1.1 General

Northrop Consulting Engineers (Northrop) have been engaged to provide high level due diligence reporting

services for the proposed new community housing development at the site of 11 Gibbons St, Redfern NSW 2016.

Figure 1 – Site Location Plan

This document provides the maximum demand (see Appendix A) calculation based on AS/NZS: 3000 Table C3

which is based on the information given in emails sent and phone correspondence.

The purpose of this report is to;

• Provide high level advice regarding the Electrical Services infrastructure to the site;

• Report on Northrop’s site investigation to confirm site constraints and existing services for the proposed site

including:

Water Supply Infrastructure;

Sewerage Infrastructure;

Natural Gas Infrastructure;

Electrical Power Infrastructure.

• Provide a preliminary high level budget estimate for the Residential Apartment Complex.

1.2 Limitations and Exclusions

The limitations and exclusions of this report are as follows:


• The following assessment is based upon Dial Before You Dig documentation, as well as correspondence with

Authorities, and all Request for Tender information provided by the Client;

• Underground routes have not been documented as accurate as possible with the use of a subcontractor with

Ground-Penetrating Radar (GPR) technology. If excavation works are to be undertaken in this area,

contractors are to undertake their own Dial Before You Dig submission and services searches and not rely on

the provided documentation.


2. HYDRAULIC INFRASTRUCTURE

2.1 Sydney Water Sewer Infrastructure

The development has access to the following Sydney Water sewer mains:

• DN 225 Vitrified Clay sewer main located within Gibbons Street;

• DN 225 Vitrified Clay sewer main located within William Lane.

2.1.1 Sewage Generation

Preliminary sewage generation rates have been estimated in accordance with the Sewerage Code of Australia -

Sydney Water Edition, WSA-02-2002 (2009). A number of assumptions have been made in estimating sewer

generation rates:

• 154 unit yield for the proposed development;

• Building height exceeds 25m effective height;

• On grade carparking only, with no below ground basement carpark proposed;

• 3.0 Equivalent Persons (EP) / dwelling has been adopted;

• Demands from other building classifications i.e. commercial, back of house, are currently unknown and have

being excluded from the calculations.

Table 1 – Sewerage Generation Estimate

Yield (Units) EP1 ADWF (kL/d)2 ADWF (L/s)3 PDWF ‘d’ Factor4 PDWF (L/s)5

154 462 83.16 0.97 2 1.94

Notes:

1. Based on 3.0 EP / ET.

2. Average Dry Weather Flow (ADWF) based on 180 L/EP/day.

3. Based on 0.0021 L/s / EP.

4. Peak Dry Weather Flow (PDWF) from Figure B.1 of SW ed. WSA 02-2002-2.2.

5. ADWF x d Factor.

2.1.2 EP Capacity Limitations for Reticulation Sewers

Per the below table from the Sewerage Code of Australia - Sydney Water Edition, WSA-02-2002 (2009), the

existing sewer mains in close proximity to the site meet the minimum size limitations to cater for the site.

However, the existing catchment area and current EP loading on these sewer mains is currently unknown. It is

possible that these mains are currently at peak capacity and are unable to cater for additional loading without an

increase in pipe size. Final determination of any upgrade works required will be subject to Sydney Water

assessment and approval under a Section 73 Application.

Table 2 – EP Capacity Limitations for Reticulation Sewers

Pipe Size (DN) Maximum Allowable EP

150 600

225 1,600


300 3,200

2.2 Sydney Water Potable Water Infrastructure

The development has access to the following Sydney Water potable water mains:

• DN 150 DICL water main located within Gibbons Street;

• DN 150 CICL water main located within Marian Street.

2.2.1 Potable Water Demand

Preliminary water supply demand rates have been estimated in accordance with AS/NZS 3500.1. A number of

assumptions have been made in estimating the water supply demand rates:

• 154 unit yield for the proposed development;

• Building height exceeds 25m effective height;

• On grade carparking only, with no below ground basement carpark proposed;

• Demands from other building classifications i.e. commercial, back of house, are currently unknown and have

being excluded from the calculations.

Table 3 – Potable Water Demand Estimate

Table 2.2 Potable Water Demand Estimate

Yield (Units) Approx. Demand per Unit Total Demand Supply Size Required (DN)

154 0.066L/sec 10.27 L/sec 100

Per the above table the existing water mains in close proximity to the site meet the minimum size limitations to

cater for the site. However, the existing flow rates and pressure available from these water mains is currently

unknown. It is possible that these mains are currently at peak capacity and are unable to cater for additional

loading without an increase in pipe size or the introduction of on-site pressure booster pumpsets and/or water

storage tanks. Final determination of any upgrade works required will be subject to Sydney Water assessment

and approval under a Section 73 Application and submission of a water main pressure and flow test application to

assess the capacity of the existing infrastructure.

2.2.2 Flow Demand Calculations

2.2.2.1 Fire Hydrant Service

Assessing the development against AS 2419.1 Table 2.1 has determined that 2 fire hydrants will be required to

flow simultaneously which constitutes a system flow rate of 20 L/sec. This is based on the development

comprising three or more stories with fire compartment floors area <5,000 m2.

Table 4 – Fire Hydrant Service Demand

Number of Fire Hydrant Outlets Required to Discharge

Simultaneously According to Building

Classification and Area


Building Classification

(see BCA)

Fire Compartment

Floor Area m2

No. of Fire Hydrant Outlets

Required to Flow

Simultaneously

2, 3, 5 and 9

(1 or 2 stories contained)

≤1,000 1

2, 3, 5 and 9

(1 or 2 stories contained)

>1,000

≤5,000

2

2, 3, 5 and 9

(3 or more stories contained)

≤500 1

2, 3, 5 and 9

(3 or more stories contained)

>500

≤5,000

2

6, 7, and 8

≤500 1

6, 7, and 8 >500

≤5,000

2

All Classes Sprinklered >5,000

≤10,000

2

All Classes Sprinklered >10,000 2

All Classes Unsprinklered >5,000

≤10,000

3

All Classes Unsprinklered >10,000 3 plus one additional fire hydrant

for each additional 5,000m2 or part

thereof

2.2.2.2 Fire Sprinkler Service

Assessing the development against AS 2118.1 has determined that the highest hazard classification will be

contributed by the on-grade carparking which will constitute an Ordinary Hazard 2 classification, with a system

flow rate of 12L/sec.

2.2.3 Fire Services Water Storage

Based on the pressure and flow test results received from Sydney Water, the existing infrastructure will be

inadequate to cater for the site’s fire services demands. As such, on-site water storage and pressure booster

pumpsets will be required to make up for the shortfall. Further, as the proposed building will be in excess of 25m

effective height, additional water storage will be required to meet the Grade 1 fire sprinkler water supply

classification in accordance with AS2118.1.

The volume of on-site storage suggested in this document is to meet the hydrant and sprinkler demands in

accordance with the relevant Australian Standards (AS 2419.1and AS 2118.1) and the BCA Volume 1. Due to the

early nature of this feasibility assessment, it is currently unknown if window drenchers would be required to

protect openings within close proximity to building boundaries, and as such window drencher service demands

have being excluded from the below calculations.


2.2.3.1 Tank Sizing Calculations

Table 5 – Fire Services Water Storage Tank Sizing

Fire Service Storage Required

Fire Hydrant Service 25,000L

Fire Sprinkler Service (2L/sec water main shortfall

make-up x 1.2 (hydraulic gain) x 60 minutes)

8,640L

Fire Sprinkler Service Grade 1 Supply (12L/sec

system demand) x 1.2 (hydraulic gain) x 60 minutes)

51,840

Total Water Storage Required 85,480L

2.3 Jemena Natural Gas Infrastructure

The development has access to the following Jemena natural gas mains:

• DN 100, 1,050kPa gas main located within Gibbons Street;

• Capped DN 32, 210kPa gas main located at the corner of Marian Street and Gibbons Street;

• DN 100, 1,050kPa gas main located within Marian Street;

• Capped DN 32, 210kPa gas main located at the corner of Marian and Regent Street.

The existing natural gas mains in close proximity to the site appear to be of an adequate size and pressure to

service the proposed development, however, it is possible that these mains are currently at peak capacity and are

unable to cater for additional loading without an increase in pipe size.

Northrop is aware that St. George Community Housing provide individual instantaneous water heaters to each

unit as part of their strata metering strategy. This will result in an increase in the overall site demand against a

typical residential development which would provide a centralised water heating plant. Final determination of any

upgrade works required will be subject to Jemena assessment through a connection application process through

their online portal once site demands have being finalised.

2.4 High Voltage Infrastructure

The Energy Authority serving the site is Ausgrid.

The site appears to be well serviced with high voltage (HV) infrastructure with a HV feeders on Gibbons Road

(the red line indicates the underground HV feeder). The site is currently fed by two service mains from poles SY-

6244 & SY-6242 on the existing low voltage network located along Gibbons Road.


Figure 2 – Existing Electrical Infrastructure

Based on the preliminary Maximum Demand calculation in Section 3.1 of this report, it is likely that a development

of this magnitude is required to be serviced by on-site by a 1000 kVA Kiosk Substation. Please note that this

advice is based on the assumption that the existing gas supply will be used to power cooking appliance and water

heaters. Should the building footprint not allow for an outdoor substation, a chamber substation is an alternative

solution.

It is likely that a new HV cable will be need to be installed directly through a straight through junction located

along Gibbons Rd. This will provide a ring feed from the newly installed substation, which means two feeds will be

coming into the substation. The new feed will require approx. 20m-25m of trenching and cabling as there are no

existing spare ducts.

The section of cable in front of the property may have to be undergrounded should the development application

state so – past projects indicate that such a scenario is likely to play out for the proposed site as well.

2.5 Low Voltage & Street Light Infrastructure

The front of the property contains Low Voltage (LV) “110 AAC” style cabling (please see figure below). Depending

on the DA conditions, there may be a requirement to underground the cables in the front of the property should

the development application state so.


Figure 3 – View from the Front of the Property

The existing overhead street light cable can also be moved underground as part of the development consent

conditions.

The removal of all the overhead conductors will also result in the removal of two poles in front of the property. A

new street light column might be required to ensure lighting compliance.

Poles to be

removed


2.6 Communications

Currently, nbn™ has not installed infrastructure in the area. However, as the premises will have more than 100

units then nbn™ will provide services to the property. NBN rollout expected in 2019.


3. BUDGET ESTIMATE

3.1 High-Level Budget Estimate

This indicative budget estimate is based on a high-level review of the proposed development along with previous

experience with similar projects.

We have allowed for the maximum 154 residential units as determined in the correspondence by St. George

Community Housing.

This a Class 5 estimate as described in AACE International Recommended Practice No. 18R-97: ‘Cost Estimate

Classification System – As Applied in Engineering, Procurement, and Construction for the Process Industries’. An

extract from 18R-97 follows:

In providing budgetary advice, Northrop Consulting Engineers has exercised the skill, care and diligence of a

Consulting Engineer experienced in the relevant discipline. The advice given is for a specific project, by a specific

client for a specific purpose. It is a condition of the use of this budgetary advice that it will not be used for any

purpose other than the specified project, client and purpose as shown below:

Project Name: 11 Gibbons St, Redfern Client: St. George Community Housing

End Usage: Due Diligence Estimate Class: 5


Northrop Consulting Engineers does not provide Class 1 or Class 2 estimates. Where these classes of estimates

are required, we recommend engagement of a specialist Quantity Surveyor with experience in the specific type of

project.

3.1.1 Electrical Services Budget Estimate

Item Description Amount

1. 154 apartments at $17,000.00 $2,618,000.00

2. Substation Option 1: 1,000kVa Substation (excluding trenching)*; $180,000.00

3. Substation Option 2: Chamber Substation(excluding trenching)*; $250,000.00

Total Option 1 + 15% Contingency $3,217,700.00


*Note: Trenching will depend upon the connection points which can only be finalized once an application is made

to Ausgrid.).

3.1.2 Hydraulic Services Budget Estimate


1. 154 apartments at $16,000.00 $2,464,000.00

2. Natural Gas Main Extension $35,000.00


3.1.3 Wet Fire Services Budget Estimate


1. 154 apartments at $5,000.00 $770,000.00

2. Fire Sprinkler Pressure Booster Pumpset $17,000.00

3. Fire Hydrant Pressure Booster Pumpset $20,000.00

4. Water Storage Tank (above ground, sectional panel type) $25,000.00

Total Option 2 + 15% Contingency $956,800.00

3.1.4 Disclaimer

• The above prices (see Appendix B) are based on industry knowledge, RLB’s Riders Digest 2016, and

Rawlinson’s Australian Construction Handbook 2016, reflecting an objective view of industry prices. It should

be noted that Northrop Consulting Engineers are not quantity surveyors;

• Allowances where otherwise unknown, have been extracted from documentation detailing typical allowances

and requirements based on similar developments;

• Northrop Consulting Engineers reserves the right to adjust the above figures based on further developed

documentation and information for the project;

• This budget estimate has been provided in assistance with the client to offer a broad understanding of the

scope and cost of works at this stage. At no given time shall Northrop Consulting Engineers assume

responsibility of market figures;


• The above figures shall be treated only as a guideline and is subject to change with further development of

design;

• It is assumed that the above costs will be subject to tenderers and market value. These figures have been

produced as a means of advice and not subject to cost comparison throughout any stage of this development;

• We understand the client and all relevant parties have read through the provided figures and information as

part of this disclaimer and will not object the rights and responsibilities set out by Northrop Consulting

Engineers.

3.1.5 Assumptions

It is assumed all buildings will be constructed in a single stage, no allowances have been made for

staging/phasing of buildings.

3.1.6 Exclusions

• Professional fees other than Level 3 ASP;

• Local authority contributions;

• Escalation of construction prices from date of budget estimate to date of tender;

• Contingency;

• Builders works;

• GST;

• Authority fees and charges other than cost of physical substation;

• Demolition works;

• Reinstatement of surfaces;

• Temporary services and connections;

• Latent conditions, unspecified heritage works and the like;

• Special site conditions;

• Professional fees;

• Rock excavation.


4. APPENDIX A – SYDNEY WATER INFRASTRUCTURE


5. APPENDIX B – JEMENA NATURAL GAS

INFRASTRUCTURE


6. APPENDIX C – MAXIMUM DEMAND CALCULATION


7. APPENDIX D – STATEMENT OF AVAILBALE

PRESSURE AND FLOW

Documents

Infrastructure Due Diligence Report