2022 NCC Seminars: Volume Three - Part B5 cross connection control

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[Music] Next we move into part  

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B5, cross connection control. There have been  major changes to this part for 2022 and a new DtS,  

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specification 41, has been added that  prescribes hazard ratings for a limited  

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list of known hazards. Scenarios and hazard  ratings were elevated from the informative  

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appendix in ASNZS 3500.1 in NCC 2019. You  will remember the old appendix F we all loved. 

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The new work has been updated and  the list of hazards which have  

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not been reviewed since they were  first included, have now changed.  

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These scenarios and the allocated hazard ratings  have now been reviewed and updated for NCC 2022,  

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to ensure that the appropriate level of protection  is applied. So firstly let's look at part B5 in a  

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little detail. What do these changes look like?  Well, firstly we have a Performance Requirement.

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Water services must be designed and installed so  as to operate in a way that avoids the likelihood  

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of contamination of any part of the drinking water  supply and minimises any adverse impact on the  

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building occupants, the network utility operators  infrastructure, property, and the environment. We  

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have added a verification method for assessment of  hazard ratings - more on this shortly - plus added  

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a number of the DtS provisions. One provision I  want to specifically bring to your attention is  

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the new DtS for 2022 which is B5D5 unprotected  water service. It is where pipework and outlets  

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supplied by a drinking water source, downstream  of an individual protection backflow prevention  

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device, are considered to convey drinking  water from an unprotected water service.  

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Another is B5D6 rainwater, which refers the  user back to a clause in AS/NZS 3500.1 2018,  

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that covers backflow provisions for rainwater.  This new clause does not change the stringency  

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from NCC 2019, it just adds it and makes  it a lot clearer and easier to find.

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Introducing Specification 41, new for 2022.  This year we have introduced a standalone  

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specification for prescribing hazard ratings  for known hazards. As I mentioned earlier,  

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it is sort of replaces the old appendix F  that was previously seen in AS/NZS 3500.1.  

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The hazard rate is prescribed in specification  must be used for selecting the required  

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backflow prevention device for the purposes of  compliance with the Deemed to Satisfy provisions.  

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Let's go into it deeper shall we. In  Specification 41 in NCC 2022 we identify  

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some of the more known hazards into protection  types like individual zone and containment.  

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The diagram on the slide clearly identifies  how these types relate to an installation.  

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It is important to note, in some jurisdictions  regulations issued under the water supply  

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legislation and or rules set out by the  network utility operator may prescribe  

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containment protection which differs from this  specification. This is a sample from S41C4 high  

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hazard installations equipment for the purpose  of identifying individual protection. You'll  

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see a mix of new hazards and some other hazards  that have been updated since the last 2019 NCC.  

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Specification 41 contains over 60 separate  installations across low, medium and high  

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hazard ratings and each with the hazard rating  and protection requirements shown, but I need to  

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reiterate that this is a DtS provision so needs  to be followed, but no matter how extensive the  

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list or how long it grows there will always be new  and innovative products that come to the market.

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So where a situation arises which is not listed  in specification 41 the appropriate hazard rating  

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may be determined as a Performance Solution.  This Performance Solution can be developed  

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using verification B5 V1. Let's move on to the  verification method part of the compliance level.  

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This is another example of where we move  from a DtS to a Performance Solution.

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B5V1 and following the clause numbering that  we've seen, the V for verification method,  

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Part B for water services, 5 for cross connection  control, and V for verification method.  

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The verification method is a risk assessment  tool that can be used to assess the level  

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of risk posed by an installation. As the slide  states, a hazard exists wherever it is possible  

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for a water service to be contaminated by  an actual or potential cross-connection  

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so your risk assessment must  include potential cross-connections.  

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The introduction of Specification 41 is really  exciting because now we have a risk assessment  

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method to provide a nationally consistent approach  to meeting the Performance Requirements of the  

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PCA and it will make it much easier for both  practitioners and regulators to ensure that the  

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drinking water supply is adequately protected.  So let's explore a little more. It is an easy  

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to follow 5-step process for determining the  hazard rating for individual and zone protection.  

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These 5 areas are: building class as per the  NCC definition in part six of the governing  

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requirements; on-site water service type;  drinking water use; the cross-connection type;  

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and the extent of the actual or potential  contamination. Each area provides a score  

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or numerical value. Scores are allocated  and sum to provide a total score:  

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0 to 3 no hazard, 4 to 7 low hazard, 8 to 10  medium hazard, and above 11 a higher hazard.  

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It's important to note the intent of  this verification method is to provide a  

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consistent means of determining hazard ratings  for situations not listed in Specification 41.  

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The verification method is not intended to enable  any lowering of hazard ratings already prescribed  

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in Specification 41. Let's look at a couple  of examples. An apartment block 20 stories  

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with mixed use retail on the lower levels, and an  underground car park with a car valet operation.  

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In this example we are to assess the zone  protection rating for a basement car wash.  

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We look into the Spec 41 and don't see  it listed. So let's do the assessment.  

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We look at the building class and  I've got here listed that it's a 2-3,  

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well actually it's probably a 6, but it gives  us a score of 2. The on-site water services,  

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network utility operated supply water, or recycle  and fire watering services gives it a score of 3.  

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What is the drinking water use? Well the drinking  water is connected to the residential units and  

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to the retail units, and to the car wash, and  the car wash may use chemicals for most uh for  

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for mud breaking and or waxing so that gives us  a score of 2. The cross connection type; well,  

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there's lots of potential cross connections  when you have the chances of untrained  

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people doing connection, so that gives us a  level of 2, and the extent of contamination.  

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Well this is a high-rise building, there could be  more than 100 people. That gives us a score of 3.  

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Cumulatively we add that up and that  comes to 12, which is a high hazard.

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The next slide tells us an example for something  you are confronted with on an everyday basis.  

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It is a new piece of equipment that you have  never seen before. So what is the hazard rating?  

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The manufacturer says it is no danger to the water  supply so only needs low hazard protection, but a  

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steam-powered chicken plucker? Common sense would  suggest it uses cold water and maybe heated water?  

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There are feathers and possibly blood and faeces  etc. One person may think it proposes a high  

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hazard risk in contradiction to the manufacturer's  recommendations so let's see. The building  

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class - we review this again. Two, 3 or maybe a  6 if it's a shop or a works in a shopping center.  

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On-site water services network utility water  supply service only so we get a score of 2.  

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Drinking water use - well it's connected to the  appliance and there is no way to determine if any  

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internal approved backflow prevention is required,  so that gets a score of 3; a cross connection to  

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type - well it's a small food processing facility  so we'll give that a score of 1; and the extent of  

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contamination - again it's a residential building  with more than 100 people so that gives us a score  

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of 3. Cumulative score equals 11 so it's a  high hazard as might have been considered

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