diff --git a/src/industry.h b/src/industry.h
--- a/src/industry.h
+++ b/src/industry.h
@@ -21,6 +21,8 @@
 typedef Pool<Industry, IndustryID, 64, 64000> IndustryPool;
 extern IndustryPool _industry_pool;
 
+static const Year PROCESSING_INDUSTRY_ABANDONMENT_YEARS = 5; ///< If a processing industry doesn't produce for this many consecutive years, it may close.
+
 /**
  * Production level maximum, minimum and default values.
  * It is not a value been really used in order to change, but rather an indicator
diff --git a/src/industry_cmd.cpp b/src/industry_cmd.cpp
--- a/src/industry_cmd.cpp
+++ b/src/industry_cmd.cpp
@@ -2857,7 +2857,7 @@ static void ChangeIndustryProduction(Ind
 	if ((i->ctlflags & INDCTL_NO_PRODUCTION_INCREASE) && (mul > 0 || increment > 0)) return;
 
 	if (!callback_enabled && (indspec->life_type & INDUSTRYLIFE_PROCESSING)) {
-		if ( (byte)(TimerGameCalendar::year - i->last_prod_year) >= 5 && Chance16(1, original_economy ? 2 : 180)) {
+		if (TimerGameCalendar::year - i->last_prod_year >= PROCESSING_INDUSTRY_ABANDONMENT_YEARS && Chance16(1, original_economy ? 2 : 180)) {
 			closeit = true;
 		}
 	}