diff --git a/scenarios/s3_multipart.js b/scenarios/s3_multipart.js
index 5252370..e5981da 100644
--- a/scenarios/s3_multipart.js
+++ b/scenarios/s3_multipart.js
@@ -36,18 +36,18 @@ const generator = datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV
 
 const scenarios = {};
 
-if (WRITERS < 1) {
-  throw 'number of VUs performing write operations should be greater than 0';
-}
-
-if (WRITERS_MULTIPART < 1) {
-  throw 'number of parts to upload in parallel should be greater than 0';
-}
-
 const write_vu_count = parseInt(__ENV.WRITERS || '0');
 // write parts in parallel
 const write_multipart_vu_count = parseInt(__ENV.WRITERS_MULTIPART || '0');
 
+if (write_vu_count < 1) {
+  throw 'number of VUs performing write operations should be greater than 0';
+}
+
+if (write_multipart_vu_count < 1) {
+  throw 'number of parts to upload in parallel should be greater than 0';
+}
+
 if (write_vu_count > 0) {
     scenarios.write = {
         executor: 'constant-vus',