diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 96a5291cbfa94c38405d70ab7c62df3a50821c3d..edbe668ccb27b0554a94ed4b9d7deace7924183f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -8,6 +8,7 @@ LCG:
     script:
         - yum install -y cmake python3 zsh which libtirpc libicu libglvnd-glx pcre2-utf16 libXrender libSM glibc-devel zlib-devel git-lfs
         - source /cvmfs/sft.cern.ch/lcg/views/LCG_104/x86_64-el9-gcc13-opt/setup.sh
+        - export NPROC=8
         - ./install.sh
         - source tools/setup.sh
         - ctest --test-dir build/Darwin --output-junit Testing/Temporary/test_report.xml -j$(nproc)
diff --git a/install.sh b/install.sh
index 2e4218c50ef5664846174b9834247e42ef14a56c..89c418aa07438f3d6577a27fb23fa1f32cbb9158 100755
--- a/install.sh
+++ b/install.sh
@@ -30,9 +30,11 @@ fi
 
 set -x
 
+[ -n "$NPROC" ] || export NPROC=$(nproc)
+
 # Download and build supporting tools
 cmake -B build $(correction config --cmake) "$@"
-cmake --build build --target install -j$(nproc)
+cmake --build build --target install -j$NPROC
 
 source tools/setup.sh