18 FEATURE
Actual pipe sizing must be done according to SANS 10252-1 and sizing will also depend on the pipe one is using as different materials require different considerations . Bear in mind the length of the pipe determines the resistance to flow and the lower the delivery volume and pressure .
Cold Water distribution As mentioned earlier there is a great pressure variance , hence the need to balance the hot and cold water pressures . This is now written into the 10254 compulsory standard . This also requires that a pressure control valve at point of entry to the building . If it cannot be done at point of entry , one is required to lead an overflow pipe from the control valve to outside the building .
Hot Water Distribution Such distribution is normally through a storage water heater , commonly referred to as a geyser . With technology development and energy requirements demanding more energy efficient systems , the need to appreciate the role of each becomes more critical . SANS 10400 XA requires that 50 % of hot water generation must be from an alternative source like solar , heat pumps and other methods .
The instantaneous water heater is growing in SA also with its own niche in the heating market .
Both Natural Gas and LP Gas are playing a role in the hot water space and either gas is required to be installed by a qualified gas installer . Such training is offered by the LPGas Association and plumbers are encouraged to expand their expertise into this field .
So , the storage tank now has a broader role to play but whichever and whatever methods are chosen it is essential that both safety and application be considered . Whether a residential house or a massive commercial building , safety is of prime importance , as is the correct design and installation .
The temperature and pressure safety valve , with a fail-safe thermostat , ensures the water is kept at an acceptable point . Hereto valves also fall under certain standards so the need to ensure compliant valves are used is critical as with compliant hot water storage tanks . While the standards call for strainers and say nothing about filters , it is the filter that keeps tiny particles away from damaging the cartridges and valves . Refer to box below for a technical overview on filters .
SANS 10254 – the installation , maintenance , replacement and repair of fixed electric storage water heating systems says it all and only qualified plumbers may work on such geysers . Bear in mind SANS 10254 is under review and public comments have closed and are being considered . There are specific standards to which parts of the whole apply as well .
• SANS 151 – Fixed electric storage water heater . ( ESWH )
• SANS 181 – Thermostats for ESWH
• SANS 198 – Functional control and safety valves for domestic hot and cold water supply systems .
• SANS 752 – Float valves
• SANS1848 – Geyser drip trays
• SANS 1042 – the wiring of premises
• SANS 10252 - Water supply installations for buildings
Conclusion This is a huge topic and a feature on its own would never do it justice . However , we have attempted to provide a broad view and emphasise the standards and water quality that all have an impact on the supply of hot and cold water . Compliancy is the critical issue , failing which the customer will have many problems . Above
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