1 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA THE NATIONAL BUILDING REGULATIONS (as issued in terms of THE NATIONAL BUILDING REGULATIONS AND STANDARDS ACT 104 OF 1977) The National Building Regulations (NBR) was amended by a notice in the Government Gazette on 11 September 2011 to include the first chapter on environmental sustainability. This regulation came into effect on 11 November 2011. As part of the amendments to include Regulation XA, some other regulations also needed to be changed to make provision for additional requirements as per Regulation XA. The following were added to Regulation A7: (m) where provided, the location, type and capacity of water heating installations; and (n) where provided, details of fenestration and insulation required to satisfy the energy usage requirements of regulation XA. To comply with Regulation A7(m) it should be noted that it is not only the position (location) of the water heater that is required, but also a description of the type as well as details of the installation. This must be read together with SANS10252-1 and therefore complete water layout drawings for water heating installations are required. Similar, to comply with Regulation A7(n), window and door schedules as well of sections through roofs etc. will be required to show compliance. The following were added to Regulation A19: (c) Where regulation XA is satisfied by a competent person in accordance with the requirements of SANS 10400 Part XA, the competent person who is responsible for such determination shall on completion of the construction and commissioning of the building submit to the local authority a fully completed Form 4 as contained in SANS 10400-A. It is important to note here that in terms of SANS10400-XA competent persons are required to certify certain aspects although it is seen as a deemed-to-satisfy requirement. The
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1 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
THE NATIONAL BUILDING REGULATIONS (as issued in terms of THE NATIONAL BUILDING REGULATIONS AND STANDARDS ACT 104 OF 1977) The National Building Regulations (NBR) was amended by a notice in the Government
Gazette on 11 September 2011 to include the first chapter on environmental sustainability.
This regulation came into effect on 11 November 2011. As part of the amendments to include Regulation XA, some other regulations also needed
to be changed to make provision for additional requirements as per Regulation XA.
The following were added to Regulation A7:
(m) where provided, the location, type and capacity of water heating installations; and
(n) where provided, details of fenestration and insulation required to satisfy the energy
usage requirements of regulation XA.
To comply with Regulation A7(m) it should be noted that it is not only the position (location)
of the water heater that is required, but also a description of the type as well as details of
the installation. This must be read together with SANS10252-1 and therefore complete
water layout drawings for water heating installations are required.
Similar, to comply with Regulation A7(n), window and door schedules as well of sections
through roofs etc. will be required to show compliance.
The following were added to Regulation A19:
(c) Where regulation XA is satisfied by a competent person in accordance with the
requirements of SANS 10400 Part XA, the competent person who is responsible for
such determination shall on completion of the construction and commissioning of the
building submit to the local authority a fully completed Form 4 as contained in SANS
10400-A.
It is important to note here that in terms of SANS10400-XA competent persons are required
to certify certain aspects although it is seen as a deemed-to-satisfy requirement. The
2 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
competent persons here is not necessarily a competent person (energy efficiency) as
defined by SANS10400-XA, but can be a person that can prove that he is competent in that
specific field, for example energy demand and consumption calculations and fenestration
calculations.
This will omit the need for local authorities to “check” plans for compliance as the competent
person will be required to submit Form 2 to be accepted as a competent person for that
specific task and thereafter certify in Form 4 that the work was executed as per the design
approved.
SANS10400-XA
The national standard SANS10400-XA provides a solution (recipe) for compliance with
Regulation XA, which are the minimum requirements. If the designer needs to show
compliance with the regulation by using any other means it is seen as a rational design or
assessment as per Regulation A19.
The primary function of this document is to give guidance on how to comply with Regulation
XA by using the solutions as given in SANS10400 XA, but will also provide guidance on
what to do if the designer cannot comply with Regulation XA by following the solutions
given in SANS10400 XA.
3 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
WHICH TYPE OF BUILDINGS HAS TO COMPLY WITH REGULATION XA? Regulation XA1 reads as follow:
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 storage 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 their 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.
Regulation A20 defines these building types as follow:
A1 Entertainment and public assembly
Occupancy where persons gather to eat, drink, dance or participate in other recreation.
A2 Theatrical and indoor sport Occupancy where persons gather for the viewing of theatrical, operatic, orchestral, choral, cinematographical or sport performances.
A3 Places of instruction Occupancy where school children, students or other persons assemble for the purpose of tuition or learning.
A4 Worship Occupancy where persons assemble for the purpose of worshipping.
C1 Exhibition hall Occupancy where goods are displayed primarily for viewing by the public.
C2 Museum Occupancy comprising a museum, art gallery or library.
E1 Place of detention Occupancy where people are detained for punitive or corrective reasons or because of their mental condition.
4 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
E2 Hospital Occupancy where people are cared for or treated because of physical or mental disabilities and where they are generally bed-ridden.
E3 Other institutional (residential)
Occupancy where groups of people who either are not fully fit, or who are restricted in their movements or their ability to make decisions, reside and are cared for
E4 Health care Occupancy which is a common place of long term or transient living for a number of unrelated persons consisting of a single unit on its own site who, due to varying degrees of incapacity, are provided with personal care services or are undergoing medical treatment.
F1 Large shop Occupancy where merchandise is displayed and offered for sale to the public and the floor area exceeds 250 m2.
F2 Large shop Occupancy where merchandise is displayed and offered for sale to the public and the floor area does not exceed 250 m2.
F3 Wholesaler's store Occupancy where goods are displayed and stored and where only a limited selected group of persons is present at any one time.
G1 Offices Occupancy comprising offices, banks, consulting rooms and other similar usage.
H1 Hotel Occupancy where persons rent furnished rooms, not being dwelling units.
H2 Dormitory Occupancy where groups of people are accommodated in one room
H3 Domestic residence Occupancy consisting of two or more dwelling units on a single site.
H4 Dwelling house Occupancy consisting of a dwelling unit on its own site, including a garage and other domestic outbuilding, if any.
H5 Hospitality Occupancy where unrelated persons rent furnished rooms on a transient basis within a dwelling house or domestic residence with sleeping accommodation for not more than 16 persons within a dwelling unit
The sections of buildings where the main occupancy is excluded above but where the
section fits one of the above descriptions have to comply with Regulation XA, for example:
A motor dealership’s (garage) can be classified as a B2 (medium risk commercial) and is
therefore excluded from compliance with Regulation XA. However, the building does
contain office space (G1) and exhibition areas for sale purposes (F1 or F2) and these
sections of the building do have to comply with Regulation XA.
5 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
WHAT ABOUT EXISTING BUILDINGS AND ALTERATIONS TO EXISTING BUILDINGS? The regulation states that “buildings and extensions to buildings in respect of which plans
and specifications are to be drawn and submitted in terms of the Act” need to comply. Two
questions arise from this, namely
1. For which buildings are plans to be drawn and submitted for approval?
2. Is it the extension or the whole of the existing building that must comply?
All new buildings need to comply with the regulations. It should also be noted that approval
to erect a building was given by a local authority as per the plans submitted and approved.
Any changes to the approved building plan may be seen as illegal building work as the Act
clearly states that approval must be granted by the local authority for the erection of all
buildings. The change of use (ex. converting a dwelling (H4) into an office (G1), may require
the submission of a building plan as it may cause the building now not to comply with the
functional regulations in the NBR for the new occupancy. It may then be required by the
local authority that certain aspects of the building being made compliant.
Extensions to buildings, as well as the affected sections of the existing building, have to
comply with the energy efficiency regulations. As the existing building had to comply
previously with the regulations before approval was granted, it will still be seen as
complying with the NBR and no changes to the existing part to comply with energy usage
regulations will be required.
All buildings that were erected illegally, with other words with no approved building plans or
that differ substantially from the approved building plans will have to be submitted as a new
application and therefore will have to comply with the latest regulations, including energy
usage in buildings, as per the NBR.
6 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
THE BUILING ENVELOPE AND SERVICES AS PER REGULATION XA1(b) There are two ways that can be used to comply with Regulation XA:
1. By minimising the use of energy while maintaining comfort levels
2. By ensuring that the building envelope and services are as such that it will not cause
the unnecessary use of energy to maintain comfort levels.
Option 1 will most likely be used for the design of complex buildings where a multi-
disciplinary team is appointed and Option 2 for most residential and small scale building
designs.
This document will concentrate on the Building Envelope and Services.
A common error made by designers of buildings is to isolate the different components that
have to be complied with and not to see them as an integrated solution on how to comply
with the NBR.
Clause 4.2.1 (b) list eight (8) aspects that the designer must comply with to satisfy the NBR:
• Building Orientation
• Shading of the northern wall
• Fenestration
• Floors
• Walls
• Roof assembly
• Services that use or control the use of energy
• Hot water supply requirement
Non-compliance with only one of the above will result in a non-compliance with the
requirements of the NBR. It should also be noted that compliance with fenestration as per
SANS10400-XA cannot be achieved if compliance with shading and building orientation are
not met. There is no restriction on the type of frame and glass of the fenestration to be
used, so the conventional use of steel or aluminium frames with clear glass is acceptable.
7 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
BUILDING ORIENTATION
The orientation of the building must be as per SANS204.
The North Sector is indicated as between 337.5° (NNW) and 22.5° (NNE), but the ideal
orientation will be as per the composite graphs showing the energy usage for heating and
cooling of buildings in six major cities in South Africa. These graphs indicate that an
orientation outside -15° to 15° will result in an increased energy usage for heating and
cooling in the buildings.
The orientation of the façade with the major area of glass of the building therefore should
ideally be between 345 and 15 (approximately true north) and the façades facing east,
west and south should be provided with minimum fenestration for compliance with
ventilation and lighting. The longer axis of the building should be east-west.
SANS10400-XA goes further by stating that the building must be compact in plan, rooms
that are used most be paced on the northern side and that the size and number of windows
on the eastern, western and southern sides be restricted to only those needed for
compliance with SANS10400-O. Big windows on these sides of the building will have the
result that the heat gain or loss will be more than a building that complies with the
requirements.
Fig. 1: Orientation sectors with orientation as per SANS204 indicated between 345° and 15°
8 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
If such orientation cannot be achieved, SANS10400-XA refers the designer to the solutions
as per SANS204 (Energy Efficiency in Buildings) where the designer, by choosing specific
glazing through a series of calculations, can prove that the requirements of the building
envelope was not compromised.
SHADING
SANS10400-XA requires shading to the northern wall to be as per the requirements of
SANS204. This shading must exclude summer solar radiation.
The figures in SANS204 indicate that:
• the sun angle must be taken into consideration and
• provide definitions for distances (P, G and H)
To comply with this requirement is more complicated that it appears.
First, the concept of “summer” must be defined. There is an astronomical summer and
meteorological summer. Because shading is caused by blocking the rays of the sun, it is
therefore logical to use the definition of “astronomical summer”. In BOU/E9701, "Solar
Charts for the Design of Sunlight and Shade for Buildings in South Africa." (CSIR) the
summer period requiring shading is September 23 to March 21 with an additional shading
period suggested from March 21 to May 15. Therefore, summer must be regarded as the
period from the 23rd of September to the 21st of March and during this period the shading
provided must exclude the sun rays.
By acknowledging this, it is now quite easy to determine the sun angle to be used: that will
be basically the same as the latitude of the site where the building is to be erected.
Before the designer can determine the sun angle, the following basics must be understood:
• P is the horizontal distance from the edge of the shading device (roof overhang,
canopy etc.) to the surface of the glass – it includes the distance that the glazing
(window) is set back into the wall
• H is the vertical distance from the base of the glazing (window sill or threshold of
glass doors) to the underside of the shading device (roof overhang, canopy etc.)
9 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
• G is the vertical distance from the head of the glazing (lintel) to the underside of the
shading device (roof overhang, canopy etc.)
• Ø is the angle of the sun during the period defined as summer
From the above the following can be derived: the height of the glazing plus the value of G
will give you the value of H.
Fig. 2a: Shading illustrated
10 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
It is important to remember that the shading applied to the northern wall (P) should not be just to the front of the glazing, but also to the sides of the glazing to provide shading to the glazing during the whole day.
Fig. 2b: Shading illustrated
Fig. 2c: Shading illustrated
11 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
By knowing the sun angle as well as the H-value (that can be measured from drawings) it is now possible to determine the P-value (shading required).
For example:
A building in Tarkastad with a maximum window height on the northern façade of 1 500mm
and a G-value of 300mm.
Tarkastad is situated on latitude 32°. The H-value is 1 800mm. The P-value can now be
calculated as follow:
Fig. 3: Sun angle illustrated
12 GUIDANCE ON HOW TO COMPLY WITH REGULATION XA
Ø = 32°, H = 1 800mm
TanØ = P/H, therefore
P = TanØ × H
P = Tan32 × 1 800
P = 0.62 × 1 800
P = 1 116
This means that the shading to be provided to the northern wall to comply with
SANS10400-XA must not be less than 1,116m!
The following table provides the latitude as well as the value of TanØ for most of the towns