50
FEATURES
<< Continued from page 48
and is caused by a moving ‘plug’ of water in the waste pipe. A
partial vacuum is created at the outlet of the trap, thus causing
siphonage to take place.
When the trap is not being used, the rate of water evaporation
depends on the relative humidity of the air in the room. The rate
is approximately 2.55mm per week, so a 25mm seal would last
for 10 weeks.
Dean Cane, operations manager at Modern Plumbing, says
that while all waste water traps are pretty easy to install,
better quality traps generally have fewer leaks. He believes the
telescopic pipes could be a bit longer, though. “The bottom
part of the trap is now plastic and is easily broken. We have
no problem with the flexi traps. In general, the consistency of
waste water trap manufacture in South Africa is pretty good.”
He insists traps must have the correct water seals, as some
have been found to be too shallow.
Compliance
Compliance of waste water traps in South Africa is governed by
parts one and two of SANS 132, which covers the requirements
for ‘P’, ‘S’, and dip-tube bottle waste traps moulded from
suitable butyl or EPDM rubber compounds and designed for use
in domestic applications, including baths, sinks, showers, and
other fitments.
“Each and every application can differ and, therefore,
the supply of the correct unit is vital. Getting the correct
information from the client is of utmost importance,” continues
Coombes. “Many clients get confused between oil separators
and grease traps. A grease trap is for the hospitality industry,
that is, for cooking fats, and an oil separator is for the motor
industry, meaning, motor oils.”
Working out specific flow rates will confirm the sizing of the
units required for both oil/water separators and grease traps.
He says the difference between locally manufactured traps and
imported ones predominantly lies in the pricing thereof.
“Some imported products are of superior quality and meet ISO
standards, but are not as affordable as locally manufactured
units. The lead time for locally manufactured units is also a lot
shorter than the imported units,” Coombes explains.
He says the future of local waste water trap manufacturing
looks positive. “It seems the councils throughout South
August 2017 Volume 23 I Number 6