Ventilation Calculations - Rinnai Brivis CC315 Series Installation Manual

2.9

VENTILATION CALCULATIONS

For installation of internal heaters in a room, enclosure, residential garage, or plant room with natural ventilation
conditions, ensure adequate ventilation is available by utilising the following formulae:
Installation of a gas appliance in a room or enclosure for properties approved for
construction prior to 31st March 2014
a. Determine if the unit(s) MJ/hr rating for each cubic metre of the room or enclosure, is greater than 3 MJ/hr per m
Example:
Unit rating (Ur)
Room volume (Rv) = 1m x 1m x 2.4m = 2.4m
Ur/Rv
As the result if greater than 3 MJ/hr per cubic metre of the space, additional ventilation is required.
b. Two permanent openings are required, each equivalent in area to the determined value A. The lower vent shall
be located close to the floor or at burner level for a Downflow unit. The upper vent shall be located at or above
the top of the unit. The two openings may be combined as long as the above conditions are met.
Determine free ventilation area using A = T x F, where:
A = minimum free ventilation area, mm
T = total gas consumption of all gas appliances, MJ/hr. e.g. CC320I V2 = 90MJ/hr
F = factor (detailed in the table below)
Table 1. Ventilation F Factors
Gas appliance location
Gas appliance in a room or enclosure
Gas appliance in a plant room
* Directly to outside means through an outside wall, into a cavity vented to outside, into an
underfloor space or roof space vented to outside.
Installation of a gas appliance in a room, enclosure, residential garage or plant room for
properties approved for construction after 31st March 2014
c. Determine if the unit(s) MJ/hr rating for each cubic metre of the room, enclosure, residential garage or plant room
is greater than 0.4 MJ/hr per m
Example:
Unit rating (Ur)
Room volume (Rv) = 1m x 1m x 2.4m = 2.4m
Ur/Rv
As the result if greater than 0.4 MJ/hr per cubic metre of the space, additional ventilation is required.
Refer to AS/NZS 5601 for natural ventilation requirements.
Note: For all other applications, e.g. Mechanical Ventilation, refer AS/NZS 5601.
Brivis
= 120MJ/hr
= 120/2.4 = 50 MJ/hr per m
2
Source of Ventilation
Directly to outside*
Via an adjacent room
Directly to outside*
Via an adjacent room
.
3
= 120MJ/hr
= 120/2.4 = 50 MJ/hr per m
3
3
3
> 0.4 MJ/hr per m
3 3
10
Factor F
300
600
150
300
Ducted Gas Heater IM
.
3