Westwood Primary School Maple Grove

Cambridge PE15 8JT

Mechanical Services Stage 4 Part L2A Summary

Date 4 August 2017

Prepared by Audley Franklin

Design Engineer

Kier Services

The Business and Technology Centre, Bessemer Drive

Stevenage

SG1 2DX

T 01483 731218

Client – Kier Services Stevenage

DOCUMENT CONTROL SHEET.

Project Title Westwood primary School Part L2A Summary

Doc Title Part L2A Summary

Doc Ref KWS-00-XX-SP-M-0001

Revision v.01b

Status Stage 4

04-08-2017

Record of Issue

Issue Status Author Date Check Date Authorised Date

v.01 Stage 3 N. Sullivan 15.05.17 D.Thomas R. Evans

v.01a Stage 3 N. Sullivan 19.06.17 D. Thomas R. Evans

v.01b Stage 4 A. Franklin 04.08.17 A. Kaminiarz 04.08.17 I.Papanikolaou 04.08.17

Revision History Remarks

v.01a Air source heat pump changed to gas fired condensing boiler with hot water generation. Photovoltaic Panel Array system added.

Distribution

Organisation Contact Copies

Kier Stevenage office Ioannis Papanikolaou 1e

This summary report is presented by Kier Services in respect of a preliminary Stage 3 Part L2A assessment for Westwood Primary School, Cambridge and may not be used or relied on by any other person or by client in relation to any other matters not covered specifically by the scope of this report. Notwithstanding anything to the contrary contained in the document, Kier Services is obliged to exercise reasonable skill, care and diligence in our performance. Kier Services shall not be liable except to the extent that it has failed to exercise reasonable skill, care and diligence, and this report shall be read and construed accordingly. The document has been prepared by Kier Services. No individual is personally liable in connection with the preparation of this document. By receiving this document and acting on it, the client or any other person accepts that no individual is personally liable whether in contract, tort for breach of statutory duty or otherwise.

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Index

Stage 4 Design – Part L2A Summary 5

Criterion 1 - Achieving the Target Emission Rating 5

Criterion 2 - Assessment – Limits on design flexibility 6 Criterion 3 – Solar Gain Check 8 Appendices 9

1. As Designed BRUKL Document 9 2. As Designed – Criterion 3 Solar Gain Check 16 3. As Designed – Stage 3 EPC 17 4. Input Summary 19 5. System and Plant Summary 23 6. Zone and System assignment 27 7. Annual CO² Emissions 28 8. Construction Specification details 29

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Westwood Primary School Stage 4 Design - Part L2A Summary Criterion 1 – Achieving the Target Emission Rating A preliminary energy assessment has been conducted for the new extension building at Westwood Primary School, Cambridge. The assessment has been calculated in line with the National Calculation Methodology (NCM). In order to meet the requirements of Criterion 1 of the approved document, the Carbon Dioxide (CO2) emissions rate from the proposed development, the Building Emissions Rate (BER), should be less than the Target Emissions Rate (TER).

Energy Consumption by End Use (kWh/m²)

System

kWh/m²

Actual Notional Heating 20.06 19.85

Cooling 0 0

Auxiliary 0.84 0.82

Lighting 9.29 13.77

DHW 9.85 8.95

Equipment* 14.03 14.03

Displaced Electricity 5.14 0

Total kWh/m²

34.91

43.38

*Equipment energy is unregulated thus excluded from the total

Part L2A 2010 CO² Emission

Results

TER 13.6

BER 9.1

Pass Rate 33.0 %

Status

PASS

The results of the annual CO2 emissions analysis indicates that the proposed design is performing better than the minimum requirements of the Building Regulations and achieves an improvement of 33.0 % over the Part L2A 2013 Target Emission Rate:

6

.

Criterion 2 Assessment – Limits on design flexibility The following design parameters have been used in the energy assessment and comply with Criterion two of the approved document:

Building Fabric Performance Details

Element

Value

Ground Floor Weighted U Value (W/m²K)

0.22

External Wall Weighted U Value (W/m²K)

0.26

Roof average Weighted U Value (W/m²K)

0.18

Window average Weighted U Value (W/m²K)

1.66

Glazing Total solar transmission (g-Value)

0.4

Design air permeability @ 50 Pascal’s (m³hr/m²)

5.0

HVAC and Lighting Performance Details

Detail

Value

Heating utilising a condensing gas fired boiler - Seasonal Efficiency rated at 94

LTHW distribution delivery efficiency (%)

95

DHW distribution delivery efficiency (%)

95

DHW storage tank insulation thickness (mm)

50

Occupied rooms have incorporated natural ventilation through opening windows

Y

7

HVCA and Lighting performance (continued)

Toilet Extract Fan Specific Fan Power (SFP) (W/l/s)

0.3

Classrooms General Lighting Power (W/m²) / Target Lux level 9 / 310

Offices General Lighting Power (W/m²) / Target Lux level 12 / 400

Store General Lighting Power (W/m²) / Target Lux level 2 / 50

Circulation General Lighting Power (W/m²) / Target Lux level 5 / 100

Toilet General Lighting Power (W/m²) / Target Lux level 10 / 200

Reception General Lighting Power (W/m²) / Target Lux level 8.5 / 200

Display, Lighting efficacy (lumen/circuit watt)

22

Whole Site electrical power factor

<0.9

BMS system with the ability to draw attention to ‘out of range’ values on HVAC systems

BMS system with the ability to draw attention to ‘out of range’ values on for lighting

All fans and pumps to be fitted with variable speed equipment.

Manual On/Auto off presence detectors (PIR) in all teaching spaces, stores, and offices. Auto on/ Auto off presence detectors (PIR) in all circulation areas and toilets.

Photocell control to all occupied rooms. Daylight sensors in teaching and office spaces with independent control. Photocell sensors are on a time clock.

Parasitic Power of PIR and daylight sensors of 0.25 W/m²

PV Array added to the south facing roof of the new extension building. PV Array consist of 20 No panels with an overall combined area dimension of 34.0m² The following PV panel efficiency profile has been applied

Irradiance (W/m²) Efficiency Factor

0 12

500 12

1000 12

Energy Production by Technology = 5.14 (kWh/m²)

Based on the new building floor area of 677 m²

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Criterion 3 – Solar Gain Check Part L 2A 2013 Criterion 3 for limiting solar gain in buildings. It states that any space that is occupied and / or air conditioned must be considered against the requirement. The limiting value for any façade is set by calculating the total solar gain between April to September through an eastern facade which has a 900mm glazed section with a g value of 0.68. A preliminary calculation has been undertaken for Westwood Primary School using the TAS Thermal Dynamic modelling software. We would note other software is available and they may produce different results. If required a further assessment will need to be undertaken as part of Stage 4 detailed design. The glazing area has been modelled as detailed in the proposed design assuming a total solar transmission (G-value) for the glazing of 0.4. It is recommended that the glazing g-value of the larger rooflights of the break out space are lowered to 0.3 to ensure Criterion 3 compliance. The daylight factor analysis has no internal blinds installed in rooms. The thermal model has included for external canopies on the outside walls to the following areas;

South facing façade above class room Ref Nos 018, 021, & 024

East facing façade above the main lobby entrance The results from the assessment indicate that the spaces are complying with criterion 3. Refer to the attached result sheet in the appendix.

Full details and the results for Criterion 3 compliance can be found on the ‘As Designed’ BRUKL Output documents dated 4.8.2017.

Please note this assessment is based on the following Architectural Plans. 1078782-KWS-BW-00-DR-A-2000-PROPOSED GROUND FLOOR PLAN Dated - July 17

1078782-KWS-BW-XX-DR-A-7300 WINDOW SCHEDULE-SHEET 1OF2 Dated - July 17

1078782-KWS-BW-XX-DR-A-7301 WINDOW SCHEDULE-SHEET 2OF2 Dated - July 17

1078782-KWS-BW-XX-DR-A-7302 HIGH LEVEL WINDOWS & ROOFLIGHTS SCHEDULE Dated - July 17

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Appendix Part L2A - As Designed Compliance documents

1. As Designed - BRUKL Certificate

10

11

12

13

14

15

2. As Designed – Criterion 3 Solar Gain Check

16

17

3. As designed – Stage 4 Energy Performance Certificate

18

4. Input Summary

19

20

21

22

5. System and Plant Summary

23

24

25

26

27

6. Zone and System assignment

28

7. Annual CO2 Emissions Comparison

29

8. Construction Specification Details

a) External Wall

30

b) Roof

c) Ground Floor

31

d) Glazing