Retrotec FanTestic Integrity (ISO) - Manual (Page 26)

rev-2014-10-27
Page 26 of 50
©Retrotec Inc. 2012
Mass of agent being discharged.

“Initial concentration” [% volume] - calculated, not entered
The initial concentration, as a percent of volume, of agent in the enclosure immediately
after a complete discharge (i.e. the concentration of agent at the beginning of the Hold
time), calculated based on the agent mass, and enclosure details. Initial concentration is
expressed as a percentage. A value will be calculated once you have entered both a
quantity and the “Maximum flooded volume”.

“Design concentration “
The agent design concentration, which will be specified by the fire protection engineer
designing the system.

“Minimum concentration”
The minimum concentration is the final concentration in the enclosure at the end of the hold
time. It is set by default to 85% of the “Design concentration”.

For Australian ISO14520 users, the user can choose to over-ride the default value for Minimum
concentration:
Checking the box allows you to enter any “Minimum concentration” and select a value that is
less than 85% of design. By doing so would mean you were not fully compliant with the letter
of the Standard.
Standards require that, at the end of the hold time, the agent concentration must be greater
than 85% of the Design at the Minimum protected height. To place this in perspective, most
countries do adhere to this requirement but some do not, notably Australia.
The Initial concentration must be equal to or greater than the Design. In cases Initial
concentration is greater than the Design, the Minimum must still be based on Design, not the
Initial.
Entering a Minimum concentration smaller than 85% of Design will increase retention time if:
1. There is Continuous Mixing, or
2. Descending interface is chosen and He is used. If He is not used then there will be no
change.
In the case of “Continuous mixing”, the same items are displayed: