Link

https://www.cibse.org/knowledge/knowledge-items/detail?id=a0q200000090MYHAA2

Application

Domestic Hot Water

This standard calculates the diversity based on

•  Number of tapping points
•  Type of the 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 (1.19 * N + 18.8 * N^0.5 + 17.6) / (37.5*N), in which N is the number of dwellings.

The diversified flow rate for one dwelling is calculated based on the default power 37,5 kW as mentioned in the DS 439 (CIBSE CP1 2015).

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Variant for high DHW usage

We also support the variant for high DHW usage. With this calculation method, the diversity factor decreases according to the formula (0.0417 + 0.015 * (0.0555N-0.0417) + 0.0775 * sqrt(0.0555N-0.0417)) / N*0.0555), in which N is the number of dwellings. The concurrent flow rate for one dwelling is calculated based on the default power 38 kW as mentioned in the F:101.

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Applies diversity

•  inside the dwelling
•  outside the dwelling

Requires recalculation of DHW flows?

No.