Four precast concrete standards will be revised, with major changes expected for SANS 1215.
The Concrete Manufacturers Association’s NPC (CMA’s) technical committee, chaired by technical director, Taco Voogt, has formed a working group to revise four precast concrete standards: SANS 1058 (concrete paving blocks), SANS 1215 (concrete masonry units), SANS 677 (interlocking concrete pipes) and SANS 542 (concrete roof tiles).
Once completed and agreed to by various interested parties, the revised standards will be published by the South African Bureau of Standards (SABS).
The SANS 1215 masonry standard includes testing procedures for dimensions, squareness, compressive strength, drying shrinkage, expansion, rewetting and soundness/consistency. The last two amendments to this standard were drafted in 2013 and are currently still being circulated for comment.
The CMA’s SANS 1215 working group is faced with two options, to either revise and update the existing standard, which was historically based on the British masonry standard that no longer applies in the United Kingdom (UK), or to adopt the European standard BS EN 771-3, a supporting standard for Eurocode 6 – Design of Masonry Structures. At this stage, it is likely that the latter will be adopted under the auspices of the SABS with a South African annex to reflect local requirements.
“There is a complication, however, and that is the revision of the National Building Regulations through the addition of SANS 10400XA, which deals with energy-efficiency and sustainability,” Voogt points out. “Its introduction means that concrete masonry manufacturers must comply with stringent energy requirements and right now there isn’t one that meets the standard, especially in single-skin walls. The proposed regulations will make South African buildings among the most thermally efficient in the world, but at what cost? New buildings, especially in the affordable and low-cost housing sectors, will become anything but affordable and double-skin cavity walls will become the norm,” he says.
South Africa’s paving standard, SANS 1058, was extensively revised in 2010 when a test based on compressive strength was replaced with tensile splitting, abrasion resistance and water absorption, and again in 2012 when the criteria for tensile splitting and abrasion testing were lowered, and the water absorption test was placed on a voluntary footing. The current initiative seeks to remove all reference to compressive strength as it is deemed irrelevant to paver performance and to place the water absorption requirement into an annex.
Some concrete pipe manufacturers have requested an annex on jacked pipes to be inserted in SANS 677 and a working group has been convened by Rocla’s Gerhard Rossouw for that purpose.
No changes are proposed for the roof tile standard, SANS 542, apart from rectifying a minor omission for on-site testing which simply entails the insertion of a missing zero on one of the test schedules.
The CMA is also monitoring the effect that the revision of the National Building Regulations through SANS 10400L-Roofs may have on the application of concrete roof tiles.
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