An Examination of Building Domestic Water Services

Time: 15:10 - 15:30

Date: 10/10/2018

Evolving building functional requirements introduces challenges in estimating hot and cold water supply demands to ensure that designs can satisfy the operational needs of a building in a cost efficient design whilst addressing key public health considerations e.g. Legionella risk, water quality etc.

An efficiently designed domestic water supply system (which also takes account of periods of low usage) is dependent on a well-engineered circulation system and storage or re-heat arrangement. The design of such domestic water systems typically rely on a fixture unit or demand unit method to establish the design peak flow rate and pipe sizes, whilst storage volumes are calculated using the same design guides typically based on litres stored per person. However, the final storage capacity is often amended due to engineering experience and discretion in response to knowledge regarding recharge time. Contributory factors such as the building water usage and turnover (water profile), occupancy times, and sanitary specification (low water use appliances) should also be considered.

Even though Legionnaires’ disease outbreaks are infrequent (circa 8 to a million in the UK) they are potentially life threatening, which may be avoidable through engineering design and operational side maintenance and management. The successful control of Legionella bacteria is a combination of good technical engineering design and client side control management. One of the engineering key considerations for this examination of domestic water systems should be to review the sizing guides/methodologies to account for modern practices; this will also require more research data analysis and promotion of knowledge sharing of raw, live consumption data from actual buildings.

This presentation discusses an examination into domestic water systems with consideration to bacteria growth, the importance of sizing the systems and water storage appropriately and the effect design standards and legislation have on expected operational performance. Furthermore, a brief summary of services issues is presented along with potential methods to mitigate excessive capital cost, running costs and aforementioned public health issues.


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