Compliance DocumentsTraining Series

G7 Natural Light

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© 2009 Building Networks. All Rights Reserved.

No part of this work may be reproduced, adapted, modified, copied or transmitted in any form or by way of example only, written graphic, electronic, mechanical, reprographic, photocopying, recording, taping or information retrieval systems, without written permission of Building Networks Ltd.

Designed by Building Networks Ltd

Published: Version 1; October, 2009

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Content

Introduction

Symbols

Download Requirements

NZ Building Code Clause G7

Activity

Navigating Your Way Around the Compliance Document

References

Definitions

Verification Method

Acceptable Solution

Activity Answers

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nzIntroductionThis training module is based on the Department of Building and Housing (DBH) Compliance Document G7 Natural Light, Amendment 1 effective 1 December 1995.

The New Zealand Building Code clause G7 was first published in July 1992. A compliance document is for use in establishing compliance with the New Zealand Building Code. There are also other methods of compliance which are detailed in the New Zealand Building Code Handbook.

For the document history please refer to the inside cover of the document.

Symbols

Where you see this symbol you are being asked to complete an activity using the Clause G7 Document.

Activity 1

Where you see the symbol you should pause to read this carefully as it is an important tip or note.

For this course you will need to download

• Compliance Document Clause G7 Natural Light from www.dbh.govt.nz

Tip

It is recommended that you make yourself familiar with the preface to theNew Zealand Building Code Handbook that both describes the status of Compliance Documents and explains alternative methods of achieving compliance.

Tip

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All Compliance Documents commence with a copy of the relevant NZ Building Code clause.

Activity 1

Review the NZBC clause for G7 [pages 3-4 of the Document]

Q.1 Fill in the blanks for the objective of clause G7.1: The objective of this provision is to safeguard people from illness or loss of amenity due

to ………………………………… from natural …………………………..and the outside environment.

Q. 2 Complete the functional requirement statement for Clause G7 below [G7.2] Habitable spaces shall provide: _________________________________________________________________

_________________________________________________________________

_________________________________________________________________

_________________________________________________________________

Q.3 Consider the performance requirements and answer the questions below: [G7.3.1] For what percentage of the standard year shall natural light provide an illuminance of no less than 30 lux at floor level? % _________________________________________________________________

[G7.3.2] Other than being provided in suitable locations, what special feature of an opening is required to give awareness of the outside? _________________________________________________________________ _________________________________________________________________

_________________________________________________________________

Navigating Your Way Around the Compliance Document

The Compliance Document G7 Natural Light contains the following sections: [page 5]• References• Definitions• Verification Method G7/VM1• Acceptable Solution G7/AS1• An index

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Refer to the References section of the G7 Document [page 7 ] Q.1 There is one New Zealand Standard referenced in the G7 Document. Please record the reference in full below: Note: For the purposes of New Zealand Building Code compliance, referenced documents shall include any amendments issued prior to the date of the Approved Document as displayed at the foot of the page on which the reference is listed.

NZS Number Year Description Where quotedNZS

Definitions

An abbreviated list of definitions for words or terms particularly relevant to ComplianceDocument G7 are found on page 9 of the Document.

Activity 3

Go to the definitions section of G7 and familiarise yourself with the meaning of the following terms:• Adequate• Amenity• Building• Illuminance• Habitable space• Reflectance• Standard year

Definitions for any other italicised word may be found in the NZ Building Code Handbook, which contains a full list of definitions. The Handbook can be downloaded from www.dbh.govt.nz. If you do not understand any terms refer back to this reference point and look up the word in alphabetical order.

Tip

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Illuminance – may be assessed by using one of the BRE calculation methods described inNZS 6703, Appendix A.

Acceptable Solution G7/AS1

Activity 4

Carefully read Acceptable Solution G7/AS1 [pages 13 - 16] and test your understanding withthe exercises below:

Q.1 True or False? Please select the correct answer

(a) Vertical windows in external walls require glazing transmittance of no less than 0.7 T/F

(b) Where the natural light entering a building is restricted more light fittings are required T/F

(c) Interior surfaces of high reflectance can assist levels of natural light in a room T/F

(d) Vertical windows in external walls can have an area of less than 10% of floor area T/F

(e) All glazing in habitable spaces for natural light purposes shall be clear glazed T/F

(f) It is acceptable for awareness of the outside to be provided through another space T/F

(g) Building finishes have different levels of approximate reflectance T/F

Q.2 What is the necessary head height for vertical windows in external walls when the window is on One Side or Adjacent Sides of a room? What can be done in large rooms where the suggested head height is impractical?

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Activity 1:

Q.1 Fill in the blanks for the objective of clause G7.1:

ANSWER

The objective of this provision is to safeguard people from illness or loss of amenity due to isolation from natural light and the outside environment.

Q. 2 Complete the functional requirement statements for Clause G7 below [G7.2] Habitable spaces shall provide:

ANSWER

….adequate openings for natural light and for a visual awareness of the outside environment.

Q.3 Consider the performance requirements and answer the questions below: [G7.3.1] For what percentage of the standard year shall natural light provide an illuminance of no less than 30 lux at floor level?

ANSWER

75% of the standard year.

[G7.3.2] Other than being provided in suitable locations, what special feature of an opening is required to give awareness of the outside?

ANSWER

It must be transparent.

Activity 2:

Q.1 There is one New Zealand Standard referenced in the G7 Document. Please record the reference in full below:

NZS Number Year Description Where quotedNZS 6703 1984 Code of practice for

interior lighting designVM1 1.0.1

AS1 Table 2

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Review as required

Activity 4:

Carefully read Acceptable Solution G7/AS1 [pages 13 - 16] and test your understanding with

the exercises below:

Q.1 True or False? Please select the correct answer

ANSWERS

(a) Vertical windows in external walls require glazing transmittance of no less than 0.7 T

(b) Where the natural light entering a building is restricted more light fittings are required F

(c) Interior surfaces of high reflectance can assist levels of natural light in a room T

(d) Vertical windows in external walls can have an area of less than 10% of floor area F

(e) All glazing in habitable spaces for natural light purposes shall be clear glazed F

(f) It is acceptable for awareness of the outside to be provided through another space T

(g) Building finishes have different levels of approximate reflectance T

Q.2 What is the necessary head height for vertical windows in external walls when the window is on One Side or Adjacent Sides of a room? What can be done in large rooms where the suggested head height is impractical?

ANSWER

The head height must be at least half the room width. In large rooms where the suggested head height is impractical, a window area in excess of 10% of floor area may be necessary.

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Building Networks NZ LtdPO Box 12463, Thorndon, Wellington Phone: (+64) 04 472 1702Email: office@buildingnetworks.co.nzWeb: www.buildingnetworks.co.nz

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