Knowledgebase
Convention 3.08 - Strongly Ventilated Spaces
Posted by Mike Gordon on 22 July 2015 09:43 AM
Option  Brief Description
Exterior For an envelope separating the considered zone from the outside air or water
Strongly Ventilated Spaces For an envelope separating the considered zone from a space provided with one or more permanent openings (i.e., that cannot be closed), with a capacity for the supply of fresh air and extract of inside air, determined according to section 5.3 of NEN 1087, of at least 3x10¯³ m³/s per m² useable Area.
Unheated Adjoining Spaces For an envelope separating the considered zone from an unheated adjoining space, other than meant under ‘Strongly ventilated spaces’. 
Conditioned Adjoining Spaces For an envelope separating the considered zone from another conditioned zone. 
Underground For an envelope separating the considered zone from the ground.
Same Space For constructions representing the internal envelopes that separate contiguous zones which have been merged into one zone, i.e., the envelope is “contained” within the merged zone.

Where ventilation specifications are available, strongly ventilated spaces shall be defined as such in accordance with the table above:

iSBEM User Guide (February 2012) : Table 9: Options for ‘Connects space to’ field for envelopes

Note that a strongly ventilated space is an alternative to an unheated adjoining space only and is not selected in any other circumstances. Where appropriate ventilation specifications are unavailable, a zone will be considered to be a strongly ventilated space if it is unheated and is one of the following:-

1.      Any part of the building being assessed that is identified with the activity of ‘car park’

2.      Any non-heated/cooled industrial process area that has mechanical extraction/ventilation serving the whole of the zone in order to accommodate the on-going processes.

3.      Any area that has deliberate fixed openings in order to provide significant natural ventilation, e.g.:

a.      A plant room with louvered doors / vents for provision of combustion air

b.      A naturally ventilated internal, underground or basement store area with fixed openings

Note that windows that are left permanently open are not categorised as fixed openings. If in any doubt, the assessor is to assume the presence of a strongly ventilated space as a worst case default position. Site notes/evidence to be provided accordingly.