The Assessment of Alternate Building Technologies
This article from the latest issue of AKHANI, the quarterly magazine of the NHBRC, addresses the use of alternate building materials and the legal process as well as the pending changes to their manuals. It is well worth a read.
Assessment of ABT (Alternate Building Technologies)
Any house to be built in an area under the jurisdiction of a local authority falls within the scope of the National Building Regulations and Building Standards Act (Act 103 of 1977), and the regulations made in terms of that act.
The regulations include mandatory performance requirements that support the objectives of the act; that is to ensure the safety and health of the persons living or working in any building. Guidance in the application of the regulation may be found in SANS 10400: The Application of the National Building Regulations.
SANS 10400 contains prescriptive rules for any form of alternate construction that are deemed to satisfy the National Building Regulations. The application of these rules is not mandatory; therefore the owner of the house is allowed to utilise any means to satisfy the requirements of the National Building Regulations.
There are various non-mandatory ways in which one could comply with the requirements of the National Building Regulations. These are summarised as follows:
• prescriptive “deemed-to-satisfy rules”
• rational design or assessment
• a valid Agrément certificate
Prescriptive “Deemed-to-Satisfy Rules”
There are various prescriptive standards (codes of practice) that are intended to simplify the application of the regulations for alternate building technologies.
SANS 10400: The code of practice for the application of the National Building Regulations with “deemed-to- satisfy rules” is applicable for house construction in South Africa.
This code reproduces the regulations and covers provisions for building site operations, building design and construction that are deemed satisfactory. Compliance with the deemed-to-satisfy rules is a direct approach to ensure that the regulations have been applied. However, deemed- to-satisfy rules are not regulations and therefore not mandatory.
SANS 10401: The code of practice for the construction of dwelling houses in accordance with the National Building Regulations specifically covers the deemed-to-satisfy rules for housing and includes:
• conventional housing
• incremental housing
• informal housing
And lastly the National Home Builders Registration Council (NHBRC): Home Building Manuals.
The role of the NHBRC is to enforce compliance with National Building Regulation requirements by the homebuilders in the home building industry. The NHBRC home building manuals are compiled in line with SANS 10400 and SANS 10401. The NHBRC manuals have been simplified and the deemed-to-satisfy rules are more user- friendly & take alternate building technologies into account.
Any revisions to the codes are reflected in the home building manuals. Therefore, compliance with the NHBRC manuals ensures that the regulations have been applied. The rules contained in the manuals are not regulations and therefore not mandatory. The current NHBRC manuals are Revision 1.
The NHBRC’s Technical Division is currently busy with the review of the manuals in line with the revision of relevant SANS standards and codes of practice.
Rational Design or Assessment
The purpose of rational designs is to ensure “fitness-for-purpose” of the elements covered by the alternate design. Rational designs are required in respect of housing systems or components, which comprise materials and/or elements whose properties, characteristics and behaviour may be known or unknown.
In both cases, a competent person (as defined under the Engineering Profession of South Africa Act, Act 114 of 1990) is required to produce the rational design.
The rational design would includea detailed structural analysis and detail design of critical members and connection design details.
The NHBRC’s Technical Division reviews the rational designs and once it demonstrates compliance to National Building Regulations a letter of approval is issued to the alternate system owner. The performance of alternative systems is reviewed annually and the letters of approval renewed, provided that NHBRC has not received any reports of system failure.
Valid Agrément SA Certificate
Agrément SA is an independent organisation established by the Minister of Public Works and housed at the Council for Scientific and Industrial Reseach (CSIR) premises. Their primary business focus is the certification of non-standardised or innovative building products through technical assessments that verify whether the products and systems are fit for purpose.
Agrément certifies products where no national standards are applicable and their certification process is performance-based. A valid Agrément certificate will comply with the National Building Regulations and hence is accepted by NHBRC for enrollment of non-standardised and alternate housing construction.
Assessment criteria
The criteria follow an outline of the information required to perform a rational design assessment:
The system owner is required to provide rational design calculations that satisfy the National Building Regulations. The report must include design assumptions, detailed calculations, references to the necessary design standards and detailed design drawings.
The structural design calculations must clearly demonstrate structural integrity and stability, including connection details. The design calculations should have proper sketches annotated in English, using SI notation.
The submission must demonstrate that the elements so designed have adequate performance at the serviceability limit state and at the ultimate limit state.
The submission report to NHBRC should address the following topics and demonstrate compliance:
1.structural performance (strengthand stability)
2.fire resistance
3.water penetration
4. condensation
5. thermal
6. durability
7. acoustics
8.construction manual (process)
9.quality manual (quality control)
The submission must be made by the system owner and certified by a competent engineer registered by the Engineering Council of South Africa (ECSA) in a professional category in terms of Act No. 46 of 2000.
Kindly reproduced for all Owner Builder and Building Regulations viewers from AKHANI the NHBRC Magazine 2013 edition 2.
For further information on approval of Alternate Building Technologies contact the NHBRC engineer:
Mr. Paimaan Byron, on +27 (0)11 317 0087 or email: PaimaanB@nhbrc.org.za.