2022 NCC Seminars: Volume Three - Explaining quantification

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foreign [Music]  

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Now let's get into the nuts and bolts. I will  

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take you through the changes to the  Performance Requirements of the PCA.

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First thing I know you're going to ask - what is  quantification? Quantification is the expression  

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or measurement of something, and you will see  what I mean as we work our way through them.  

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A large amount of work has been undertaken in  reviewing the performance requirements of the PCA  

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to ensure that these high-level objectives of the  

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Code set out a measurable target to meet  when undertaking a Performance Solution.  

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Quantified Performance Requirements will make it  simpler to know if the solution being used will  

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meet these requirements as well as it being easier  for a regulator to confirm that solution complies.  

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The amended Performance Requirements are what  we call a policy neutral change. This means that  

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whilst the clause was changed the technical  objective has not. This is still a work in  

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progress although, however, with a number of  Performance Requirements still to be identified,  

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but over the next few slides I'll step you through  the changes so far to the requirements of 2022.

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The first Performance Requirement relates to  the flow rates of a cold water service. As  

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you can see, the 2019 requirement didn't  really give you much to work towards,  

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and determining the appropriate flow rates for  the correct functioning of fixtures is tricky.  

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The 2022 requirement is a lot more specific,  outlining a limit of 3 meters per second.  

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The reference to one percent refers to how much  time that the system would be expected to exceed  

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this maximum velocity during the period of peak  use which is referred to as the annual peak hour.

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This one is another great example. It could be  difficult to demonstrate that you have designed  

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a service to efficiently use drinking water.  However, it is easy to ensure that your showers,  

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basins and sinks use no more than 9 litres per  minute or that the toilets being used flush no  

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more than 6 and 3, or 4.5 and 3 litres. You'll  see that subclause B, however, at the bottom,  

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also allows for flexibility should a  Performance solution require. However,  

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it still works in conjunction with the first part  to provide a means of compliance measurement.

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This one is for pressure. The required pressures  of a water service is also another area which  

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has received some attention in 2022 points.  This change has provided a limit of between  

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50 kPa and 500 kPa which gives you a parameter  and is much easier to demonstrate compliance.  

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You will see that the second  subclause, subclause B,  

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will continue to provide the flexibility if  you need to work outside of these pressures.

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This one is about heated water services.  Heated water flow rates have received the same  

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treatment as cold water services. This Performance  Requirement has been broken down into reticulated  

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systems and circulatory systems. Circulatory  systems have been then separated between  

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copper systems and other pipework materials  as they can cater for different velocities.

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This one is about excessive pressure,  for the temperature and pressure relief  

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of water heaters. If you look at the 2019  requirement you might be a bit stumped on  

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what is considered excessive pressure or  what temperatures you need to limit the  

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system to in order to prevent flash steam  production. Now with the quantification,  

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a specific temperature and pressure is listed,  and again there is a degree of flexibility if  

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that performance solution being used needs  to deviate beyond beyond these limits.

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Legionella is a major ongoing  issue in warm water so another  

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area which has been updated is the  requirement for Legionella control.  

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The Performance Requirement now sets a target  Legionella count that a heated water system must  

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be designed to achieve. This limit aligns with  the advice provided by the health departments.

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With this fire-fighting water service  provision you can see that this requirement  

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is set at the 95th percentile, not one  percent as per the cold water service.  

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This works the same way but rather than exceeding  no more than one percent of the time or operating  

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correctly 99 per cent of the time, this  requirement sets a 95 per cent target.  

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This provides an additional safety factor  for fire-fighting water services to ensure  

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that the service pressures and the flow rates  for fire-fighting water service are correct.  

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The safety factor is important, as having the  right flow rates and pressures is critical in  

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ensuring that the fire-fighting water  service works when it is needed.

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And the last example is for factory plumbing  ventilation. As you can see, the quantified  

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Performance Requirement provides a limit of both  positive and negative pressures within the system.  

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This pressure limitation is to set to  ensure the trap seals are not affected  

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and continue to prevent the escape of sewer  gases into the building. This requirement  

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obviously does not apply to a vacuum drainage  system which operates in a negative pressure.

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This is the last quantification example I  have for you but watch this space for 2025  

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as we continue to work our way through  the Performance Requirements of the PCA.