Whether you are a plumber, designer or hydraulic consultant, there are many things to consider when designing and installing a plumbing system, says John Fennell from the International Copper Association Australia.

(This article was first published in the Summer 2023-24 issue of ‘Plumbing Connection’.)

DESIGN

Good design starts with a simple layout, as this helps in identifying and locating problems and enables easy maintenance. When a layout is complex, with many twists and turns, it can be more difficult to pinpoint problems such as blockages and leaks.

In a large installation when there are interconnecting ring mains around a site, it makes it very difficult to shut off the water supply when there are problems. In addition, complex heated water layouts with many interconnecting ring mains will cause disruptions to water supply in some areas, as water will always flow via the easiest path. To overcome this, balancing valves must be installed but these require regular maintenance and adjustment. A single ring main on each level, with droppers to outlets, is a better option but care must be taken that the dead legs are not too long and are regularly used. Dead legs are a source of contamination if they are not flushed or frequently used.

DRAWINGS

Clear and accurate drawings are important and provide essential information about the layout. For large buildings they are a prerequisite, but for small single dwellings they are an invaluable source of information. How many times does a plumber go to site to fix a problem, and has to chase around finding where the plumbing runs or where the drains discharge into the sewer mains?

In large buildings, detailed drawings can help maintenance personnel to understand the relationship between the different components of the system, such as the flow of water or the pressure at different points in the system. This can help them to identify and correct problems more efficiently.

One of the biggest problems for a plumber is locating the drawings in the first place, particularly if the building is some years old. Building managers are becoming less common, or, if they do exist, there may have been several changes over the time and information is lost.

For heated water circulating systems, it is mandatory for water-, weather- and fade-resistant diagrams to be permanently affixed in a prominent location at the circulating pump. Refer to AS/NZS 3500.4 for details that must be included on these diagrams.

After any change is made to the system, it is important that an updated drawing be displayed and presented to the manager or owners corporation representative.

Example of dual backflow prevention valves with associated isolation valves and ports for pressure gauges. (Image supplied by RWC, item DCV20C_RPZ20C Combo.)

MATERIALS

Selecting reliable, good-quality materials is important, as this gives the system the best chance to operate efficiently over its life. High-quality materials are less likely to leak, break down, or deteriorate, and will reduce the need for maintenance. There will be cheaper alternatives – and with the pressure on to keep the cost down, it may be an easy option but do not forget you are responsible not only for the installation, but also generally for the material choice.

Copper pipes and fittings have serviced the industry for over 100 years, and although there are occasional issues, these can easily be overcome as every plumber knows how to use the product.

ISOLATION & FAULT FINDING

When plumbing problems occur, isolation of the affected section is required in order to effect the repair. In single dwellings this is usually at the water main to the premises, but well-designed houses have isolation vales under the main sinks, allowing simple jobs such as replacing tap washers or flick-mixers without having to shut off the main water supply. This not only saves time, but also reduces the inconvenience to the other areas of the premises.

In larger buildings isolation valves are very important, as they allow maintenance personnel to isolate specific sections of a system for repairs or maintenance.

Where there are multiple apartments and dwellings, there must be an individual isolation valve installed on each branch serving an individual apartment or dwelling, accessible by the occupier from common property.

There are also mandatory requirements for isolation valves to be installed around specific equipment such as water heaters, pumps, filters, thermostatic mixing valves (TMVs), and backflow protection devices in order to allow these to be serviced or replaced.

To allow ease in fault finding in large or complex plumbing systems, the installation of pressure gauges, or at least access ports for gauges, should be installed either side of pumps and filters, as well as at critical levels in high-rise buildings, to ensure the correct design pressures are being achieved. Similarly, in complex circulating heated water systems, temperature gauges, or at least access ports for gauges, should be installed on each return line of a circulation circuit. This will allow the checking of how well the system is balanced.

REDUNDANCY

A redundant system is one that has multiple components that perform the same function, so that if one component fails, another can take over its function, allowing the system to continue operating.

Redundancy can be achieved by having duplicate pumps, filters, valves or other critical components. This helps maintenance, minimises downtime, and reduces the risk of damage or disruption to the system’s operation.

Redundancy is particularly important for critical systems, such as in hospitals, data centres or other facilities where downtime can be costly or even life-threatening. Another aspect of redundancy in critical systems is having backup water or power supplies, such as water storage tanks, generators or battery backup.

ACCESSS

All control equipment must be installed so that it is readily accessible.

Semi-flexible connector and braided hoses can only be used above surface level and in accessible locations. Similarly, thermostatic mixing valves (TMVs), pressure control, or temperature control valves must also be readily accessible. Water heaters must have unobstructed access available to all controls, tanks and to enable them to be removed.

It is important that openings to pump rooms are large enough to enable pumps to be removed without being dismantled. Sufficient space must also be provided around pumps and other equipment to allow safe access for servicing and maintenance.

In accessible areas piping must be easily identifiable to ensure correct services are being maintained. This is particularly important for non-drinking water systems to ensure cross connection does not occur.

MAINTENANCE

Regular maintenance is important because it helps to ensure the continued reliability and efficiency of the system over long term. It can help to identify and address potential problems before they become more serious, thus reducing the damage or disruption to the system’s operations.

Regular maintenance can involve a variety of activities such as inspection and cleaning equipment, checking for leaks or other signs of damage, and replacing warm or damaged components.

By identifying the addressing potential problems early on, maintenance personnel can help to prevent more serious damage from occurring, reducing the need for costly repairs or replacement.

In summary, there are many aspects that need to be considered in a good design, and it is imperative that your design meets the current regulations and fits the intended purpose. Remember: you are the one who will be responsible if it is not satisfactory.

John Fennell is the CEO of the International Copper Association of Australia. Visit https://copper.com.au