This video from the 2022 NCC Seminars discusses Part B5 cross connection control from NCC 2022 Volume Three.
[Music] Next we move into part
B5, cross connection control. There have been major changes to this part for 2022 and a new DtS,
specification 41, has been added that prescribes hazard ratings for a limited
list of known hazards. Scenarios and hazard ratings were elevated from the informative
appendix in ASNZS 3500.1 in NCC 2019. You will remember the old appendix F we all loved.
The new work has been updated and the list of hazards which have
not been reviewed since they were first included, have now changed.
These scenarios and the allocated hazard ratings have now been reviewed and updated for NCC 2022,
to ensure that the appropriate level of protection is applied. So firstly let's look at part B5 in a
little detail. What do these changes look like? Well, firstly we have a Performance Requirement.
Water services must be designed and installed so as to operate in a way that avoids the likelihood
of contamination of any part of the drinking water supply and minimises any adverse impact on the
building occupants, the network utility operators infrastructure, property, and the environment. We
have added a verification method for assessment of hazard ratings - more on this shortly - plus added
a number of the DtS provisions. One provision I want to specifically bring to your attention is
the new DtS for 2022 which is B5D5 unprotected water service. It is where pipework and outlets
supplied by a drinking water source, downstream of an individual protection backflow prevention
device, are considered to convey drinking water from an unprotected water service.
Another is B5D6 rainwater, which refers the user back to a clause in AS/NZS 3500.1 2018,
that covers backflow provisions for rainwater. This new clause does not change the stringency
from NCC 2019, it just adds it and makes it a lot clearer and easier to find.
Introducing Specification 41, new for 2022. This year we have introduced a standalone
specification for prescribing hazard ratings for known hazards. As I mentioned earlier,
it is sort of replaces the old appendix F that was previously seen in AS/NZS 3500.1.
The hazard rate is prescribed in specification must be used for selecting the required
backflow prevention device for the purposes of compliance with the Deemed to Satisfy provisions.
Let's go into it deeper shall we. In Specification 41 in NCC 2022 we identify
some of the more known hazards into protection types like individual zone and containment.
The diagram on the slide clearly identifies how these types relate to an installation.
It is important to note, in some jurisdictions regulations issued under the water supply
legislation and or rules set out by the network utility operator may prescribe
containment protection which differs from this specification. This is a sample from S41C4 high
hazard installations equipment for the purpose of identifying individual protection. You'll
see a mix of new hazards and some other hazards that have been updated since the last 2019 NCC.
Specification 41 contains over 60 separate installations across low, medium and high
hazard ratings and each with the hazard rating and protection requirements shown, but I need to
reiterate that this is a DtS provision so needs to be followed, but no matter how extensive the
list or how long it grows there will always be new and innovative products that come to the market.
So where a situation arises which is not listed in specification 41 the appropriate hazard rating
may be determined as a Performance Solution. This Performance Solution can be developed
using verification B5 V1. Let's move on to the verification method part of the compliance level.
This is another example of where we move from a DtS to a Performance Solution.
B5V1 and following the clause numbering that we've seen, the V for verification method,
Part B for water services, 5 for cross connection control, and V for verification method.
The verification method is a risk assessment tool that can be used to assess the level
of risk posed by an installation. As the slide states, a hazard exists wherever it is possible
for a water service to be contaminated by an actual or potential cross-connection
so your risk assessment must include potential cross-connections.
The introduction of Specification 41 is really exciting because now we have a risk assessment
method to provide a nationally consistent approach to meeting the Performance Requirements of the
PCA and it will make it much easier for both practitioners and regulators to ensure that the
drinking water supply is adequately protected. So let's explore a little more. It is an easy
to follow 5-step process for determining the hazard rating for individual and zone protection.
These 5 areas are: building class as per the NCC definition in part six of the governing
requirements; on-site water service type; drinking water use; the cross-connection type;
and the extent of the actual or potential contamination. Each area provides a score
or numerical value. Scores are allocated and sum to provide a total score:
0 to 3 no hazard, 4 to 7 low hazard, 8 to 10 medium hazard, and above 11 a higher hazard.
It's important to note the intent of this verification method is to provide a
consistent means of determining hazard ratings for situations not listed in Specification 41.
The verification method is not intended to enable any lowering of hazard ratings already prescribed
in Specification 41. Let's look at a couple of examples. An apartment block 20 stories
with mixed use retail on the lower levels, and an underground car park with a car valet operation.
In this example we are to assess the zone protection rating for a basement car wash.
We look into the Spec 41 and don't see it listed. So let's do the assessment.
We look at the building class and I've got here listed that it's a 2-3,
well actually it's probably a 6, but it gives us a score of 2. The on-site water services,
network utility operated supply water, or recycle and fire watering services gives it a score of 3.
What is the drinking water use? Well the drinking water is connected to the residential units and
to the retail units, and to the car wash, and the car wash may use chemicals for most uh for
for mud breaking and or waxing so that gives us a score of 2. The cross connection type; well,
there's lots of potential cross connections when you have the chances of untrained
people doing connection, so that gives us a level of 2, and the extent of contamination.
Well this is a high-rise building, there could be more than 100 people. That gives us a score of 3.
Cumulatively we add that up and that comes to 12, which is a high hazard.
The next slide tells us an example for something you are confronted with on an everyday basis.
It is a new piece of equipment that you have never seen before. So what is the hazard rating?
The manufacturer says it is no danger to the water supply so only needs low hazard protection, but a
steam-powered chicken plucker? Common sense would suggest it uses cold water and maybe heated water?
There are feathers and possibly blood and faeces etc. One person may think it proposes a high
hazard risk in contradiction to the manufacturer's recommendations so let's see. The building
class - we review this again. Two, 3 or maybe a 6 if it's a shop or a works in a shopping center.
On-site water services network utility water supply service only so we get a score of 2.
Drinking water use - well it's connected to the appliance and there is no way to determine if any
internal approved backflow prevention is required, so that gets a score of 3; a cross connection to
type - well it's a small food processing facility so we'll give that a score of 1; and the extent of
contamination - again it's a residential building with more than 100 people so that gives us a score
of 3. Cumulative score equals 11 so it's a high hazard as might have been considered