Link

https://www.en-standard.eu/din-1988-300-codes-of-practice-for-drinking-water-installations-part-300-pipe-sizing-dvgw-code-of-practice/cibse.org/knowledge/knowledge-items/detail?id=a0q3Y00000IMrmGQAT

Application

Domestic Hot Water

This standard calculates the diversity based on

•  Number of tapping points
•  Type of the tappping points
•  Design flows of the tapping points
•  Number of dwellings
• tapping points
•  Total DHW flow
•  Diversified DHW flow
•  Number of dwellings

Diversity formula

With this calculation method, the diversity factor decreases according to the formula (a * (T)^b - c) / T, in which T is (2qm + Θ(Σqf-2qm) + Asqrt(qm*Θ)sqrt(Σqf-2qm))/Σqf, in which Σqf = T = the sum of the design flows (for hot water) of all individual taps.

For apartments : a = 1.48, b=0.19, c=0.94

For hospitals : a = 0.75, b=0.44, c=0.18

For hotels : a = 0.70, b=0.48, c=0.13

diversified HIU flows.

This formula only applies when 0.2 <= T and T <= 500. It is important to note that calculation is applicable for T expressed in liter per seconds. We assume A=3.1; Θ = 0.015; qm=0.1

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Applies diversity

•  inside the dwelling
•  outside the dwelling

Requires recalculation of DHW flows?

Yes. This standard assumes a DHW regime of 15°C for cold water and 60°C for hot water, resulting in a mixed temperature of 37,5°C (when both flows are equals). If the temperatures in the Hysopt model deviate from this standard regime, the design flows for cold and hot water are first recalculated (in order to achieve a mixed design flow of 37,5°C), see Step 1 : recalculation of the tapflows for more info.

Remarks

For appartments with low volume flows, there is a small “strange“ bump in the diversity graph if you apply the formula

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No.