Improving Water Quality in Australian Schools and Hospitals

4

What are the reasons for lead being in drinking water?

It is recognised that many factors contribute to the variability and accuracy of lead concentration results from infield drinking water sampling. 12 This can make it extremely difficult to determine the true source, and/or the reasons for lead being in the water supply. Besides the quality of the actual

water source, these factors include but are not limited to:

Build up over time of a protective mineral crusting or patina on the inside of pipes Chemicals introduced into the water supply (e.g. chlorine vs chloramine)

Type of materials used in the plumbing system

Age and complexity of the plumbing system

Fluctuations in water quality (i.e. pH and alkalinity)

Usage patterns of inhabitants

Water temperature

Stability of flow rates in the system

Surface characteristics of the plumbing products used (e.g. smoothness and residues)

Stagnation and dead-leg areas

Dealing with the build-up of lead in the water due to these factors, is especially important in large and complex plumbing systems, such as those in hospitals, schools, and prisons.

Current standards and lead

In Australia, plumbing products in contact with potable water typically need to be certified to the relevant WaterMark. Some examples include: • AS 3688:2016 – Water supply and gas systems – Metallic fittings and end connectors 13 • AS/NZS 3718:2005 – Water supply – Tap ware 14 • AS 4032.4:2014 – Water supply – Valves for the control of heated water supply temperatures Part 4: Thermostatically controlled taps for the control of heated water supply temperature 15

The material compositions allowed are covered under the relevant WaterMark. The WaterMarks may also cross reference to other Australian Standards. When looking at AS/NZS 3718 for example, clause 2.2.4 references the following standards for

various copper alloys: • AS 1565 – Castings – Less than 4.5% lead • AS 1567 – Extrusions – Less than 3.5% lead • AS 1568 – Hot Pressings – Less than 3.5% lead

Made with FlippingBook Annual report