diff --git a/src/metkit/config/LibMetkit.cc b/src/metkit/config/LibMetkit.cc
index 7293b34..6af7953 100644
--- a/src/metkit/config/LibMetkit.cc
+++ b/src/metkit/config/LibMetkit.cc
@@ -76,6 +76,9 @@ eckit::PathName LibMetkit::mars2gribRuleListYamlFile() {
 eckit::PathName LibMetkit::mars2gribStatParamRuleListYamlFile() {
     return "~metkit/share/metkit/mars2grib/StatParamRuleList.yaml";
 }
+eckit::PathName LibMetkit::mars2gribIfsPrefixToLevTypeYamlFile() {
+    return "~metkit/share/metkit/mars2grib/IfsPrefixToLevTypeRuleList.yaml";
+}
 
 //----------------------------------------------------------------------------------------------------------------------
 
diff --git a/src/metkit/config/LibMetkit.h b/src/metkit/config/LibMetkit.h
index 3a1794c..b666b09 100644
--- a/src/metkit/config/LibMetkit.h
+++ b/src/metkit/config/LibMetkit.h
@@ -36,6 +36,7 @@ class LibMetkit : public eckit::system::Library {
     
     static eckit::PathName mars2gribRuleListYamlFile();
     static eckit::PathName mars2gribStatParamRuleListYamlFile();
+    static eckit::PathName mars2gribIfsPrefixToLevTypeYamlFile();
 
     static const LibMetkit& instance();
 
diff --git a/src/metkit/mars2grib/Mars2Grib.cc b/src/metkit/mars2grib/Mars2Grib.cc
index 269dda4..d1ae5d5 100644
--- a/src/metkit/mars2grib/Mars2Grib.cc
+++ b/src/metkit/mars2grib/Mars2Grib.cc
@@ -32,12 +32,14 @@ static pthread_once_t once       = PTHREAD_ONCE_INIT;
 
 static std::unique_ptr<metkit::mars2grib::RuleList> mars2GribRuleList_{nullptr};
 static std::unique_ptr<metkit::mars2grib::RuleList> statParamInfoRuleList_{nullptr};
+static std::unique_ptr<metkit::mars2grib::RuleList> ifsPrefixToLevTypeRuleList_{nullptr};
 }
 
 static void init() {
     local_mutex = new eckit::Mutex();
     mars2GribRuleList_ = std::make_unique<metkit::mars2grib::RuleList>(eckit::YAMLConfiguration{LibMetkit::mars2gribRuleListYamlFile()});
     statParamInfoRuleList_ = std::make_unique<metkit::mars2grib::RuleList>(eckit::YAMLConfiguration{LibMetkit::mars2gribStatParamRuleListYamlFile()});
+    ifsPrefixToLevTypeRuleList_ = std::make_unique<metkit::mars2grib::RuleList>(eckit::YAMLConfiguration{LibMetkit::mars2gribIfsPrefixToLevTypeYamlFile()});
 }
 
 namespace metkit::mars2grib {
@@ -54,6 +56,10 @@ const RuleList& statParamRuleList() {
     return *(statParamInfoRuleList_.get());
 }
 
+const RuleList& ifsPrefixToLevTypeRuleList() {
+    pthread_once(&once, init);
+    return *(ifsPrefixToLevTypeRuleList_.get());
+}
 
 
 void convertMars2Grib(const eckit::ValueMap& initial, KeySetter& out, const RuleList& ruleList) {
diff --git a/src/metkit/mars2grib/Mars2Grib.h b/src/metkit/mars2grib/Mars2Grib.h
index a65ab77..dc25ddf 100644
--- a/src/metkit/mars2grib/Mars2Grib.h
+++ b/src/metkit/mars2grib/Mars2Grib.h
@@ -27,6 +27,7 @@ namespace metkit::mars2grib {
 
 const RuleList& ruleList();
 const RuleList& statParamRuleList();
+const RuleList& ifsPrefixToLevTypeRuleList();
 
 /**
  * Reads specific mars keys