MVHR for passive or do I need this?

[Nic]

So at building regs drawing stage for a small timber framed house. Rendered outside, built with passive and airtightness in mind .

Architect has listed this in the info on the ventilation? Any thoughts as I thought the MVHR did all the ventilation  do I need all these extra things ? 
 

AD PART F

Ventilation to be provided by designed MHVR system.

In general:

BACKGROUND VENTILATION

In addition to natural ventilation, equal to 0.3 l/s per m' internal floor area (including 8000mm night vents), the whole building ventilation rate to be 19 l/s (one bedroom).

The whole to be in accordance with Approved Document Part F.

Kitchen and bathroom to have a mechanical vent with 100mm dia, ductwork to external air. Kitchen to have extraction equal to 60L/s (w/o cooker hood). Bathrooms to have extraction equal to 15L/s.

Kitchen extract to be Expelair GXC6, or similar, with a 15 minute over run facility.

Bathroom to be Expelair DX 2100, or similar, with a 20 minute over run wired to light switch.

NOTE:All exposed vents to have fixed grills/hoods.

A Positive Input Ventilation unit to be installed. Vent-axia wall mounted Posi-Dry Compact Pro (model 479188) with integral heating element. Duct form outside to PIV unit to be insulated.

PURGE VENTILATION

Minimum requirement is for 4 air changes per hour per room.

All rooms to have openable window area equivalent to minimum 1/20th floor area for windows that open more than 30 degrees or 1/10th for opening 15 to 30 degrees.

CONTROL OFVENTILATION

Trickle vents are to be positioned min 1700mm above floor level, where possible, and installed in accordance with BS EN 13141-1 2004. Humidity detector to be fitted to Mechanical extraction.

Installation and Commissioning Checklist to be completed by Competent and Qualified person and forwarded to Building Control.

[ProDave]

That spec appears to be the normal trickle vents and individual extract rates for a house without mvhr.

 

Once you choose mvhr all those trickle vents and individual room extract rates do not apply and you design the mvhr to a different set of constant flow rates that are also listed in building regs.