This video from the 2022 NCC Seminars discusses the changes to the Performance Requirements for NCC 2022 Volume Three.
Now let's get into the nuts and bolts. I will
take you through the changes to the Performance Requirements of the PCA.
First thing I know you're going to ask - what is quantification? Quantification is the expression
or measurement of something, and you will see what I mean as we work our way through them.
A large amount of work has been undertaken in reviewing the performance requirements of the PCA
to ensure that these high-level objectives of the
Code set out a measurable target to meet when undertaking a Performance Solution.
Quantified Performance Requirements will make it simpler to know if the solution being used will
meet these requirements as well as it being easier for a regulator to confirm that solution complies.
The amended Performance Requirements are what we call a policy neutral change. This means that
whilst the clause was changed the technical objective has not. This is still a work in
progress although, however, with a number of Performance Requirements still to be identified,
but over the next few slides I'll step you through the changes so far to the requirements of 2022.
The first Performance Requirement relates to the flow rates of a cold water service. As
you can see, the 2019 requirement didn't really give you much to work towards,
and determining the appropriate flow rates for the correct functioning of fixtures is tricky.
The 2022 requirement is a lot more specific, outlining a limit of 3 meters per second.
The reference to one percent refers to how much time that the system would be expected to exceed
this maximum velocity during the period of peak use which is referred to as the annual peak hour.
This one is another great example. It could be difficult to demonstrate that you have designed
a service to efficiently use drinking water. However, it is easy to ensure that your showers,
basins and sinks use no more than 9 litres per minute or that the toilets being used flush no
more than 6 and 3, or 4.5 and 3 litres. You'll see that subclause B, however, at the bottom,
also allows for flexibility should a Performance solution require. However,
it still works in conjunction with the first part to provide a means of compliance measurement.
This one is for pressure. The required pressures of a water service is also another area which
has received some attention in 2022 points. This change has provided a limit of between
50 kPa and 500 kPa which gives you a parameter and is much easier to demonstrate compliance.
You will see that the second subclause, subclause B,
will continue to provide the flexibility if you need to work outside of these pressures.
This one is about heated water services. Heated water flow rates have received the same
treatment as cold water services. This Performance Requirement has been broken down into reticulated
systems and circulatory systems. Circulatory systems have been then separated between
copper systems and other pipework materials as they can cater for different velocities.
This one is about excessive pressure, for the temperature and pressure relief
of water heaters. If you look at the 2019 requirement you might be a bit stumped on
what is considered excessive pressure or what temperatures you need to limit the
system to in order to prevent flash steam production. Now with the quantification,
a specific temperature and pressure is listed, and again there is a degree of flexibility if
that performance solution being used needs to deviate beyond beyond these limits.
Legionella is a major ongoing issue in warm water so another
area which has been updated is the requirement for Legionella control.
The Performance Requirement now sets a target Legionella count that a heated water system must
be designed to achieve. This limit aligns with the advice provided by the health departments.
With this fire-fighting water service provision you can see that this requirement
is set at the 95th percentile, not one percent as per the cold water service.
This works the same way but rather than exceeding no more than one percent of the time or operating
correctly 99 per cent of the time, this requirement sets a 95 per cent target.
This provides an additional safety factor for fire-fighting water services to ensure
that the service pressures and the flow rates for fire-fighting water service are correct.
The safety factor is important, as having the right flow rates and pressures is critical in
ensuring that the fire-fighting water service works when it is needed.
And the last example is for factory plumbing ventilation. As you can see, the quantified
Performance Requirement provides a limit of both positive and negative pressures within the system.
This pressure limitation is to set to ensure the trap seals are not affected
and continue to prevent the escape of sewer gases into the building. This requirement
obviously does not apply to a vacuum drainage system which operates in a negative pressure.
This is the last quantification example I have for you but watch this space for 2025
as we continue to work our way through the Performance Requirements of the PCA.