Retrotec FanTestic Integrity (ISO) - Manual (Page 23)

rev-2014-10-27
Page 23 of 50
©Retrotec Inc. 2012
Our guidance is to follow the requirements of the AHJ or to continue with past procedures. This
software will make calculations in any way you choose but the operator may want to consider
the following comments to provide a context should a decision path be needed.
1. If a definitive procedure is in place, continue with it until the new version of ISO is in
place that will eliminate the 90% requirement.
2. The vast majority of tests done worldwide and future versions of all standards will not
require protection to a mandatory 90%, so over-riding this default is a reasonable
action.

“Required protected height”
If “Over-ride default value of 90% of flooded height” checkbox is checked, enter the
minimum protected height. This height is usually measured to the top of the equipment
you are trying to protect. If not, FanTestic Integrity will calculate 90% of the flooded height
and enter this automatically for you.

“Over-ride (He) calculation”
Checking the box over-rides the H
e
calculation and instead predicts the time it would take for
the agent mixture to fall to the Minimum protected height, H
p
. Using H
p
assumes the interface
has no thickness and will make your test non-compliant but there may be reasons you want to
do this which are explained under, “Our guidance”.
The ISO 2006 Edition of this Standard requires an equivalent interface height, H
e
, be calculated
in order to reduce hold times to allow for the development of a Wide Interface that was
theorized to occur. H
e
is only used in Descending Interface calculations where no Continual
mixing occurs.
The effect of allowing the software to perform the H
e
calculation will reduce the hold time by
20% for inerts and about 35% for halocarbon chemical agents. This is done to make allowance
for the formation of a theoretical Wide Interface that would reduce concentrations in the center
of the interface below the Minimum. Since the Wide Interface was demonstrated not to occur
and changes to the Standard have been accepted, there are precedents for over-riding the
calculation:
1. H
e
was not used in the 2000 version
2. NFPA does not use H
e
3. The new version of ISO will have a different H
e
calculation that will give longer hold
times but not as long as not using H
e
at all.
4. Many countries do not use the H
e
calculation.
5. Previous versions of Retrotec software (CA2001) did not force an H
e
calculation but it
was supplied as a separate calculation for those who wanted to use it.
Our guidance is to follow the requirements of the AHJ or to continue with past procedures. This
software will make calculations in any way you choose but the operator may want to consider
the following comments to provide a context should a decision path be needed.
1. If a definitive procedure is in place, continue with it until the new version of ISO is in
place that will reduce the impact of H
e
calculations.