We are currently working on few new and existing buildings in Ireland. These buildings have either natural ventilation or mixed ventilation (natural vent + mechanical vent) strategy.

To comply with IAQp1, we have researched the following approaches with the outstanding questions:

For 100% naturally ventilated building (no mechanical ventilation):

As per LEED v4 Guidance, we need to use either ASHRAE 62.1 or local code, whichever is more stringent. Europe ACP can be used as well based on the GBCI reply.

  1. To comply with ASHRAE 62.1 Section 6.4, the following exceptions are applied:
    1. an engineered natural ventilation system, when approved by the authority having jurisdiction, need not meet the requirement of Section 6.4. We have done the dynamic modelling for CIBSE TM52 compliance (Irish TGD Part L requirements) and CO2 control strategy. We have also done the analysis for the background ventilation and purge ventilation to comply with Irish TGD Part F. Can this approach can be treated as ‘an engineered natural ventilation system’?
    2. the permanently open or controls that prevent the openings from being closed during periods of expected occupancy are required. For few existing buildings, we only have manually operable windows as per design. It is because the buildings are the historical buildings with renovation, the openable windows are slash windows which the automatic control cannot be applied. Is there any exception for windows control strategy for the existing buildings with renovation?
  2. To comply with Europe ACP: Naturally Ventilated Spaces, has anyone submitted with this approach before? Any experience are really appreciated.

For the buildings with mixed ventilation strategy (some rooms are naturally ventilated the other are mechanically ventilated):

GBCI requires to have the same standard for the entire building - both mechanically ventilated rooms and naturally ventilated rooms. For mechanically ventilated rooms, we have proved the compliance with ASHRAE62.1. However, we have only four rooms with natural ventilation in the building with manually operable windows, which means these rooms cannot meet the requirement as per ASHRAE 62.1 Section 6.4 requirements listed above. Is there any other way for these naturally ventilated rooms to comply?

Thank you very much for the help.

Chenlu Li