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When I do a test calculation for just one Process in the PEF database I receive negative values. This occurs for various PEF Processes (materials) like "Alkyd resin dispersion (self-emulsified); technology mix; production mix, at plant; 50% in water"

When I inspect the impact values on the Process level they are positive as expected, so I am very surprised that they become inverted (negative) when I do a calculation.

Your help would be much appreciated.
in openLCA by (120 points)
by (120 points)
I add the Flow as Input. In this case  "Urea formaldehyde resin".  I do "Direct calculation" of the Process.  It then shows the impact as negative values?
I find the "Urea formaldehyde resin" in the PEF database under Materials production/Organic chemicals/nan/Urea-formaldehyde resin.

1 Answer

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by (74k points)
Thank you for the further explanation - direct calculation makes a product system with autoconnect and calculates this directly, on the fly, therefore you should not use direct calculation for PEF and GaBi-like databases.