Hi, I'm working on an office C&S project.  Up until recently the MEP strategy was natural ventilation of all tenancies and for this reason the tenancy was envisaged to be modelled that way. Recently, the client has requested what you could call an "upgraded C&S" as part of the C&S package.  I.e. 50% of the tenancies will now be mixed mode using natural ventilation and mechanical cooling when required, the other 50% will remain fully naturally ventilated.  This additional scope is planned to be undertaken by the same design team to attract tenants as there currently is no tenant agreed.  Note this will not be a tenant fitout.

My questions are:

1) Can the Minimum Energy Performance modelling remain based on 100% naturally ventilated tenancies as these spaces meet ASHRAE Standard 90.1-2010​ requirements for a naturally ventilated space,

2) If 1) is acceptable can the MEP drawing evidence illustrate mechanical cooling systems to 50% of the spaces, i.e. does mechanical cooling have to be in a separate fitout MEP package?

Thanks in advance