diff --git a/kalibrierschein/siunitx-PTB.sty b/kalibrierschein/siunitx-PTB.sty
index f09eb4fdda7323bbbb8bf2c5940c20edea9467d1..e5ce6a11a8a5c7ccf7c04219f0ef98506948592f 100644
--- a/kalibrierschein/siunitx-PTB.sty
+++ b/kalibrierschein/siunitx-PTB.sty
@@ -12,6 +12,7 @@
 
 \DeclareSIUnit\torr{Torr}
 \DeclareSIUnit\mbar{\milli bar}
+\DeclareSIUnit\bar{bar}
 \DeclareSIUnit\sccm{sccm}% Standard Cubic Centimeters per Minute
 
 %%%\AtBeginDocument{%