48
FEATURES
SANS 721 —
correct at last
The fact that the fittings are
to be used above ground
also affects the required
thickness of the pipes —
this requirement had to be
incorporated into SANS 721.
SANS 721 has been a headache for years. The first
version of the standard, dictating the necessary quality
for polypropylene pipes and pipe fittings for soil, waste,
and vent applications for above-ground non-pressure
use, proved to be woefully inefficient.
By Warren Robertson
A number of municipalities found that fittings that
had passed the testing, were deteriorating after just
five years. Now there is a new version — one that
committee members are confident does what the
standard should have done the first time around.
“I am reasonably happy with the way it turned out in the
end,” says Renier Snyman, SABS technical committee
member, and Sunace technical manager. “There has been
a lot of struggle. Someone once said that SABS usually
writes technical standards; the original version of 721 was
their first political standard,” he says. “I think that was the
sentiment of a lot of people: that there was a lot of politics
involved initially, but eventually, we got our working group
together that was the right mix of people and we managed
to fix the original quite comprehensively.”
Dr Clif Johnston from the South African National
Consumer Union (SANCU) explains that the initial
committee had nobody to look after the expectations of
January 2019 Volume 25 I Number 1
the consumer; a facet that often came into play in the
development of the update.
“The issue was, is this standard setting out to judge the
best product you can make from polypropylene and stick
it on the shelf, or is it to make a product that is suitable
for use and will last the lifetime of a building?” Johnston
asks. “We came with the assertion that a typical building
life is between 50 and 80 years, so let’s make the
standard demand a minimum of 50.”
There were a number of problems with this challenge
set by SANCU. “Unmodified polypropylene isn’t great as
a raw material in UV. You have to modify it and improve it
before it can last in the conditions in which it is used in
South Africa,” says Snyman.
MORE CHALLENGES
The UV resistance problems were just one of three
large challenges the committee were forced to
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