NEW SECTION - NATIONAL BUILDING LEGISLATION : NBR-XA

- NATIONAL BUILDING STANDARD : SANS 10400-XA

Part X : Environmental sustainability in buildingsPart XA : Energy usage in buildings

Contents

● Why energy efficiency● Legislation background● SANS 10400 XA● Compliance

● Hot Water● Walls● Roofs● Floors

● SANS 204

Europe: Energy Efficiency Targets for New Residential buildings - 2020

Relative Evolution of building regulations over time (year 2000 = index 100)

-20

0

20

40

60

80

100

120

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Denmark England/Wales France Germany

Poland Spain Finland Netherlands

DK, FR, DE: evolution of building energy consumption England/Wales: Code of Sustainable homes Poland: evolution of U values walls

60% of European Homes

Homes built pre-1975

Millennium European Standards

European standards 2010

Low-consumption homes

*Annual cost to heat 100m²

€1 700 €800 €300 €100

*Estimate based on oil prices at $60 per barrel

What does this mean in monetary terms?

Eskom presents: Historical demand overview

Reserve margin aspiration = 15%

20000

22000

24000

26000

28000

30000

32000

34000

36000

38000

40000

42000

19

88

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Year

Pe

ak

De

ma

nd

an

d C

ap

ac

ity

(M

W)

Peak Demand Expected Peak Demand

Installed Capacity (MW Sent-out) Operational Capacity (MW Sent-out)

Reserve margin = 25%

Reserve margin = 20%

Reserve margin = 16%

Reserve margin

= 8-10%

40% of SA total energy currently used in buildings

≈ 35% Roof

Walls≈ 25% Glazing

Thermal bridges

≈ 10% Ground

Floor

≈ 10%

≈ 10%

Summer

Winter

Principle of insulation

Correctly insulating the building envelope in combination with energy saving techniques can control energy losses and reduce energy consumption by up to 78%

≈ 10% Air gaps

Compliance

• The provisions of the National Building Regulations shall be satisfied by:

– Adhering to the requirements of all the prescriptive regulations, or

– Complying with all functional regulations by:• Adopting building solutions that comply with the deemed to

satisfy requirements of the corresponding part of SANS 10400• Reliably demonstrating or predicting with certainty that an

adopted building solution has an equivalent or superior performance to a solution that complies with the deemed to satisfy provisions. (Rational design by competent person)

Routes to Compliance to NBR-XA

● Option 1: Rational design This alternative requires input of a professional “competent” person Thermal performance of building needs to be calculated Performance should be equal or better than specified in SANS 10400XA

● Option 2 – 4 = “Deemed-to-Satisfy”

● Option 2: Compliance to SANS 10400XA “Recipe” for building elements Requirements partially aligned with SANS 204

● Option 3: Compliance to Tables Thermal performance of building needs to be calculated Max Energy Consumption & Max Energy Demand must comply with tables in

SANS 10400-XA This alternative requires input of a professional “competent” person

● Option 4: Comparison with a compliant theoretical (reference) building Building design performance – theoretical max energy consumption & demand

shall be less than or equal to that of a reference building Building should be designed to “Deemed to Satisfy” standards Use of thermal performance calculations software accredited by Agrement SA This alternative requires input of a professional “competent” person

Regulatory Framework

• National Building Regulations and Building Standards Act, 1977 (Act 103 of 1977).

• NBR`s are issued in terms of the above act and is a compilation of various parts (A to X:–– Part A – General Principles and Requirements– Part B – Structural Design– :– Part X – Environmental Sustainability

• Part XA – Energy Usage in Buildings

• SANS 10400 is a National Standard: (Building code)– The Application of the National Building Regulations (also compiled in many

parts to correlate to the National Building Regulations)

Part XA – Energy Usage in New Buildings

• XA1 - In order to contribute to the reduction of greenhouse gases, buildings and extensions to buildings in respect of which plans and specifications are to be drawn and submitted in terms of the Act, having A1, A2, A3, A4, C1, C2, E1, E2, E3, E4, F1, F2, F3, G1, H1, H2, H3, H4 and H5 occupancies or building classifications in accordance with Regulation A20, excluding garage and storages areas contained within such occupancies, shall be designed and constructed so that they:

a) are capable of using energy efficiently while fulfilling user needs in relation to vertical transport, if any, thermal comfort, lighting and hot water; or

b) have a building envelope and services which facilitate the efficient use of energy appropriate to its function and use, internal environment and geographical location.

Equipment and plant required for conducting the business of the occupant shall be excluded from these requirements.

• XA2 - At least 50 % by volume of the annual average hot water heating requirement shall be provided by means other than electrical resistance heating including but not limited to solar heating, heat pumps, heat recovery from other systems or processes and renewable combustible fuel.

• XA3 - The requirements of sub-regulation XA1 shall be deemed to be satisfied when such building is designed and constructed in accordance with the following requirements:

a) has an orientation of the longest axis, shading, services and building envelope in accordance with SANS 10400-XA; or

b) is the subject of a rational design by a competent person, which demonstrates that the energy usage of such building is equivalent to or better than that which would have been achieved by compliance with the requirements of SANS 10400-XA; or

c) has a theoretical energy usage performance determined using certified thermal calculation software, less than or equal to that of a reference building in accordance with SANS 10400-XA.

Additional Requirements

• Competent person (where necessary) – Submit documentation– Local authority as per SANS 10400-A

• On Plans– Where provided – location, type & capacity of water heating installations

– Where provided – details of

• Fenestration

• Insulation

SANS 10400 XA Hot Water Supply – XA2

• Regulation: A minimum volume fraction of 50% of the annual average heating requirement for hot water shall be provided by means other than electric resistance heating or fossil fuels including, but not limited to:

– Solar heating– Heat pumps– Geothermal heat– Renewable combustible fuel – Heat recovery from alternative systems and processes

SANS 10400 XA2 Hot Water Supply – compliance

• The functional requirements of sub-regulation XA2 shall be satisfied when:

– 4.1.1 The population for which such building is designed is determined in accordance with Regulation A21;

– 4.1.2 The hot water demand is determined in accordance with table 2 and table 5 of SANS 10252-1:2004;

– 4.1.3 The storage requirement is based on maintenance of a hot water temperature of 60 0C;

– 4.1.4 Solar water heating systems shall comply with SANS 1307, SANS 10106 and SANS 10254 based on the thermal performance determined in accordance with the requirements of SANS 6211-1 and SANS 6211-2.

– 4.1.5 All exposed hot water service pipes (SANS 10252-1) shall be clad with insulation with a minimum R-value in accordance with SANS 204.

– 4.1.6 Thermal insulation, if any, shall be installed in accordance with the manufacturer’s instructions.

1. Roof/Ceiling systemsSANS 10400 XA Geyser systems and Pipe Insulation – XA 2

All exposed hot water service pipes shall be clad with insulation with a minimum R-value in accordance with the table below.

Internal diameter of pipe Minimum R-value

<80mm 1.0

>80mm 1.5

Determined with a hot surface temperature of 60 °C and an ambient temperature of 15 °C.

Requirements

1. Roof/Ceiling systemsSANS 10400 XA – Geyser and Pipe Insulation

• Geysers use 35 - 40% of a households energy

• System including pipes!• Reduced heating cycles• No switching on/off

• Heat loss saving Geyser blanket 21% Pipe insulation 37% Total savings 58%

Savings can vary depending on the length of the pipes insulated and the thermostat setting. Thermostat setting should ideally be 55ºC

Saint-Gobain geyser and pipe insulation solution

1 – Isover Geyser Insulation Pack (Flexible blanket & pipes)

SANS 10400 XA Energy Usage & Building Envelope – XA3

• Conceptually based on two principles:– Maximum energy demand per unit area(kVA/m2)

– Maximum annual energy consumption per unit area (kWh/m2.a)

• Dependent on building classification and climatic region

Maximum Energy Demand

1 2 3 4 5 6 7 8

Classification of occupancy of building

Description of building

Maximum energy demanda

VA/m2

Climatic zone

1 2 3 4 5 6

A1 Entertainment and public assembly 85 80 90 80 80 85

A2 Theatrical and indoor sport 85 80 90 80 80 85

A3 Places of instruction 80 75 85 75 75 80

A4 Worship 80 75 85 75 75 80

F1 Large shop 90 85 95 85 85 90

G1 Offices 80 75 85 75 75 80

H1 Hotel 90 85 95 85 85 90

a The maximum demand shall be based on the sum of 12 consecutive monthly maximum demand values per area divided by 12/m2 which refers to the nett floor area.

b The climatic zones are given in annex B.

Maximum Annual Consumption

1 2 3 4 5 6 7 8

Classification of occupancy of building

Description of building

Maximum energy consumption

kWh/(m2·a)

Climatic zonea

1 2 3 4 5 6

A1 Entertainment and public assembly 420 400 440 390 400 420

A2 Theatrical and indoor sport 420 400 440 390 400 420

A3 Places of instruction 420 400 440 390 400 420

A4 Worship 120 115 125 110 115 120

F1 Large shop 240 245 260 240 260 255

G1 Offices 200 190 210 185 190 200

H1 Hotel 650 600 585 600 620 630

NOTE 1   The annual consumption per square metre shall be based on the sum of the monthly consumption of 12 consecutive months.NOTE 2   Non-electrical consumption, such as fossil fuels, shall be accounted for on a non-renewable primary energy thermal equivalence basis by converting mega joules to kilowatt hours.

a The climatic zones are given in annex B.

SANS 10400 – XA Energy Usage & Building Envelope – XA3

• Climatic Zones

Drg.727a

SANS 10400 XA Energy Usage and Building Envelope – XA3

• Orientation– Compact in plan with most glass on the northern side

– Living spaces on northern side

– Longer axis of dwelling to be east-west

– Roof overhang to shield northern windows in midday summer sun

• Floors– If under floor heating is installed in-slab or in-screed it has to be

insulated with a minimum R-value of 1

Requirements

Where an under slab or in-screed heating system is installed it shall be insulated underneath the slab with insulation having a minimum R-value of not less than 1,0.

SANS 10400 XA – Heated Floors

Requirements

SANS 10400 XA Energy Usage and Building Envelope – XA3

• Fenestration– Buildings with up to 15% fenestration area to nett floor area per storey

are deemed to satisfy

– Buildings with fenestration area to nett floor area per storey exceeding 15% shall comply with the requirements for fenestration in SANS 204

– Air infiltration shall comply with SANS 613

Requirements

SANS 10400 XA Energy Usage and Building Envelope – XA3

• External Walls– Light weight walls (Non brick/Concrete) shall achieve a minimum R-value:

• 2.2 for climatic zones 1&6

• 1.9 for climatic zones 2,3,4&5

– Masonry walls (Brick/Concrete) shall achieve a minimum R-value of 0.35

• Double skin masonry with no cavity, plastered internally; and either plastered externally or finished with face bricks

• Single leaf masonry with a nominal thickness of at least 140mm plastered internally and rendered externally

Requirements

External walls with a surface density more than 180kg/m2 shall achieve a minimum R-value of 0.35m²K/W

The R-value depends on type of brick used.NB: Although insulation is not compulsory for external walls, we recommend that all walls are built with a minimum cavity of 50mm in all climatic zones.

Requirements

SANS 10400 XA– External Masonry Walls

SANS 10400 XA Energy Usage and Building Envelope – XA3

Metal sheet roofing fixed to metal purlins, metal rafters or metal battens shall have a thermal break consisting of a material with an R-value of not less than 0,2 installed between the metal sheet roofing and its supporting member

1 2 3 4 5 6 7

Description

Climatic zones

1 2 3 4 5 6

Direction of heat flow Up UpDown

and up

Up Down Up

R-value of roof covering material 0,3 0,36 0,30

R-value of ceiling 0,05

Added R-value of insulation 3,35 2,85 2,35 3,35 2,29 3,15

Requirements

SANS 10400 XA Energy Usage and Building Envelope – XA3

1 2 3 4 5 6 7

Description

Climatic zones

1 2 3 4 5 6

Direction of heat flow Up UpDown

and up

Up Down Up

R-value of roof covering material0,35 0,48 0,35

R-value of ceiling 0,05

Added R-value of insulation 3,30 2,80 2,30 3,30 2,17 2,8

Clay tile types of roofing assembly construction shall achieve the minimum total R-value in with the installation of insulation that has an R-value as specified below:

Requirements

Example of heat flow - UpFor a ceiling in Climatic Zone 1 to meet SANS 10400XA requirements the individual figures are added together to obtain the total R-value required

1. Roof/Ceiling systems SANS 10400 XA – Roof/Ceiling insulation

Saint-Gobain ceiling insulation solution

Isover Aerolite (Flexible Rolls)

SANS 204 Energy Efficiency in Buildings

• Far more comprehensive than the building regulations and SANS 10400 – XA

• Requirements significantly more stringent

• In the longer terms regulation to be upgraded and trend toward SANS 204

• It is a voluntary standard

• Basic minimum for green star rating

SANS 204 Requirements

• Site and building orientation– Optimization of orientation for lowest energy use

• Shading– Methods to determine projection overhang

• Building design– Floors

• Perimeter insulation of slabs <500m2• Suspended floors forming part of envelope• In-slab heating insulation

– External walls• Minimum specification of CR values (typically 80 to 100 versus SANS

10400-XA of 40)

Thermal conductivity, (K-value)

• All materials conduct heat, some better than others. Good insulation materials must have a LOW conductivity.– Eg. The heat from one side of a wall must travel very slowly towards the

other side of the wall.

• Thermal conductivity is calculated in W/mK (Watts per meter Kelvin degrees), therefore if two products with similar densities are tested at the same temperature and one has a K value of 0.040 W/mk and the other has a K value of 0.045 W/mK, the material with the lower K value insulates better.

Thermal conductivity, (K-value)

• The ability of a product to conduct heat– Steel is a good conductor of heat– Wood is a poor conductor

• Calculated in W/m.K (Watts per meter Kelvin degrees)– K values of typical building materials

• The lower the K value the lower the heat flow through the product

Typical Building Products K value ( W/m.K)

Corrugated steel roof sheets 1.000

Clay roof tiles 1.150

Gypsum ceiling board 0.170

Wooden roof truss 0.120

Polyester ceiling insulation ( 10 kg/m³) 0.045

Glasswool ceiling insulation ( 12 kg/m³) 0.040

Glasswool ceiling board ( 50 kg/m³) 0.032

Thermal resistance, (R-value)

• The ability of a product to resist the transfer of heat

• To calculate the R value you need to know (R value = )– The Thermal conductivity (K value) of the product– The product thickness

– Calculation of R-Values for typical Roof/Ceiling Construction Products

• Total R-value of a construction element (Wall or roof) can be obtained by adding the R-values of the different components

• The higher the R value the better the products thermal resistance

Thickness in meters K value

Material K-Value R-Value

W/mK mm m m²K/W

Corrugated Roof Sheet 43.000 0.8 0.0008 0.00002

Clay Roof Tile 1.150 13.0 0.0130 0.011

Wooden Roof Truss 0.120 25.0 0.0250 0.208

Gypsum Plasterboard 0.170 6.4 0.0064 0.038

Glasswool Ceiling Board (50kg/m³) 0.032 25.0 0.0250 0.781

Glasswool Ceiling Insulation (11kg/m³) 0.040 100.0 0.1000 2.500

Polyester Ceiling Insulation (10kg/m³) 0.045 100.0 0.1000 2.222

Thickness