HEALTH AND SANITATION 35
Committee / s at *** SABS when producing the long awaited and long overdue incorporation of WATER into SANS 10400 will consider SANS 893 Part 1 & 2 – Legionella . Part 1 is Risk Management and Part 2 is the control of Legionella in water systems .
The standard was established in 2013 because of the hard work of the Legionella Action Group ( LAG ) under the auspices of the NIOH . For this article , we will focus on the Control of Legionella in water systems which covers , Cooling Towers and Evaporative condensers and Hot and Cold-water systems . The standard follows with each section having its own programme , treatment , monitoring , cleaning and disinfection and management . The normative references which are INDISPENSIBLE for the application include ,
• BS 4485-3 and 4 - Water cooling towers
• SANS 241-1 Drinking water
• SANS 893 - Part 1
• SANS 1808-15 backflow prevention devices
• SANS 10252-1 water supply installations for buildings
• SANS 11731 . ISO 11731 Detection and enumeration of legionella
• SANS 31000 / ISO 31000 Risk Management
There are also the local municipal by-laws which must ensure adherence to the standards lest they end up facing a lawsuit .
The relevant ACTs referred to earlier are LAW and as one can note there are more than enough standards to hold anyone responsible should they face a lawsuit .
We will now focus on the Hot and Cold-water systems for this publication and our sister publications RACA Journal and Cold Link Africa will focus on the Cooling Towers / Evaporative side . Obviously , SABS copyright precludes us from reprinting the entire document or great chunks of it , but we can extract certain paragraphs to reinforce what has been stated before and which supports the US input .
Section 8 Hot and Cold-water systems The standard makes the point that the maintenance of water temperature throughout the distribution system and changes in demand could be simplified by changing to point of use water heaters with minimal or no storage . There is a caveat to this insofar as open tanks and large storage volumes can be eliminated by moving to mains . To do this one must have confidence in the reliability and continuity of the mains supply .
Section 9.1 General covers the design and construction of hot and cold systems .
Clearly the application plays a huge part in design , but the overriding standard is SANS 10252 – 1 which is a compulsory standard under the National Water Act as well as SANS 1808 -15 . Reference to these standards is not optional and as clearly stated in 9.1.1 b Materials for pipework , water fittings and jointing materials SHALL comply with SANS 10252-1 and backflow preventers SHALL comply with SANS 1808-15 . General issues of design , sizing , layout , construction , and commissioning appear in 10252 , the Building Regulations and bylaws .
There are very strong references to flow rates and the correct use of valves and positioning of valves . The standard is extremely vocal about multiple applications from the small to the large and flow rates are critical . An issue that the Water Efficiency Labelling Scheme ( WELS ) TC is looking at . We use WELS here as a generic term as the name may well change .
Also critical is pipe sizing . As mentioned in the US extract , the use of low-flow products with considering the impact on the ‘ backend ’ of plumbing i . e ., pipe size and pressure is an important design consideration . Logic tells one that if the flow is reduced at output , something must give because these products do not consider the pressure as they are controlling output – not pressure at input .
Maintenance and Operation Maintenance is not a well-used practice in South Africa , and we are paying a heavy price for the lack of proper maintenance as far as water quality and water loss is concerned .
** Back to Greg Stafford ’ s article in terms of Managing Risks and Plumbing Africa produced a Preventive Maintenance article in February 2022 page 17 , “ Increase profitability and customer loyalty at the same time ,” which applies just as well .
Effectively managing risks associated with building water systems takes a commitment from everyone involved , from owners and operations to engineers and plumbers ( contractors ). Managing risks must be a priority of the building owner and DISCUSSED AT THE VERY BEGINNING OF PROJECT PLANNING ( our capitals ).
Engineers should include recommended control measures in early conceptual and schematic design documents . This ensures control measures are included in initial cost estimates and creates an opportunity to discuss the owner ’ s priorities concerning managing legionella .
As the project moves through the design development , engineers should |
focus on supporting key water management principles : |
1 . |
Maintain water temperatures outside of legionella growth range . |
2 . |
Prevent water stagnation . |
3 . |
Ensure adequate disinfection . |
4 . |
Prevent scale , corrosion , and biofilm growth . |
Engineers and contractors must balance public health and safety good engineering practice , sustainability , operational efficiency , and owner requirements while also being cost conscious .”
Nothing new here and the plumber needs to be always part of this process , especially in the choice of materials and fixtures . Cost cutting is easy in the short term but will be very costly in the long term as South Africans realise the access to the courts is perhaps not as difficult as it used to be .
SANS 893-2 is a document that should be treated in the same manner as 10400 , 10252 , 10254 , 1808 and other standards referred to earlier .
Legionella can be a deadly disease if not treated correctly and its cause is where water is stored and where there is a means of creating and transmitting water droplets which might be inhaled and enter the lungs , where the bacteria can grow . Without early planning , correct product selection and qualified plumbers installing , the problem could end up on those who started the design .
* Extract provided by the National Institute for Occupational Health , National Health Laboratory Service . info @ nioh . nhls . ac . za
** Portions of this article originally appeared in the May 2022 issue of Plumbing Engineer , which is published by PHCPPROS . The author , Greg Swafford , CPD , GPD , is Technical Sales Manager , Commercial Water , for GF Piping Systems ( GF ). Visit https :// www . phcppros . com / to view the original and complete article .
*** to purchase standards www . sabs . co . za PA
August 2022 Volume 28 I Number 6 www . plumbingafrica . co . za