Best Practice Design
Water Reticulation Design Considerations
No matter what type of building we are designing for, be it a hospital, aged care, child care or residential, there is a need for us to consider the proposed water reticulation design in terms of ease of maintaining and monitoring the system to help minimise and manage the risk of Legionella and other bacteria within the water systems.
Firstly, the quality of the water supply source should be considered to determine suitability and if further treatment or filtering is required.
Cold water reticulation should be installed in locations that minimise or eliminate any heat transfer from surrounding areas such as external walls or close proximity to hot water pipes and the like.
Both hot and cold reticulation should have the ability to be easily flushed and treated and completely drained for maintenance purposes.
Other considerations such as thermostatic mixing valves (TMV) should be a type that allows flushing of the cold supply side of the valve and shower roses should not have a rose that is too fine to eliminate “misting” of the spray. Similarly tapware without aerators should be considered to again eliminate the “misting” of the water.
Pipework design should be such that there are no “dead legs” where stagnation of the water can occur. Any redundant pipework within an existing system should be disconnected at the main line and the branch replaced with a straight connection.
These are only a few areas where we can improve our designs and monitoring the systems by way of alarms or similar on thermostat controls of recirculated systems as well as any electrical heating elements in water heaters to ensure correct temperatures are maintained.
Our design of water systems are only as good as the maintenance and monitoring of the system and for this reason a comprehensive water risk management plan must be implemented in all instances to avoid any high readings of Legionella or other bacteria that may be considered a health risk.
By good designs, maintenance and monitoring of water systems and pipework we can “live” with Legionella not “die” from Legionella.
Step 1. Create an up to date schematic of the hot and cold water supply lines associated with the reticulated plumbing network.
Step 2 Maximise design performance through the minimisation of dead legs within the reticulated plumbing network.
Step 3 Incorporate multiple test points and isolation valves to facilitate flushing of lines to support the ongoing maintenance of the reticulated plumbing network. not clear.
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