Using the mechanical supply & exhaust inputs on room data
NCM System configurations allow for various inputs for Ventilation SFP’s. Depending on the System Type this is set at either the System level (Apache Systems) or Room Level (Room Query).
When space conditioning occurs locally the Ventilation SFP is Typically defined at the Room Level (Room Query).
Generally in systems where the main space conditioning load is handled at the AHU the Ventilation SFP is defined at the System Level (Apache Systems).
When the space is served by a Fan Coil System a SFP Central figure is defined at the System level and an additional SFPterminal figure defined at the room level.
The settings for room level SFP’s are commonly misunderstood. When a space has mechanical supply the defined SFP should reflect the total Supply and Extract fan power divided by the supply flow rate. This is defined in the Non-Domestic Building Services Compliance Guide.
The local mechanical exhaust is used to include for Exhaust from Toilets, Changing rooms etc. rather than to be used for general extract.
The supply ventilation rate is taken from the NCM Activity Database however the Exhaust Rate is defined by the user and applied in both the Actual and Notional Building.
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