diff --git a/core/lib/Drupal/Core/Extension/Requirement/RequirementHelper.php b/core/lib/Drupal/Core/Extension/Requirement/RequirementHelper.php
new file mode 100644
index 0000000000..c3d584af62
--- /dev/null
+++ b/core/lib/Drupal/Core/Extension/Requirement/RequirementHelper.php
@@ -0,0 +1,39 @@
+<?php
+
+
+namespace Drupal\Core\Extension\Requirement;
+
+/**
+ * Provides a helper for requirements.
+ */
+class RequirementHelper {
+
+  /**
+   * Extracts the highest severity from the requirements array.
+   *
+   * @param \Drupal\Core\Extension\Requirement\RequirementInterface[] $requirements
+   *   An array of requirements.
+   *
+   * @return int
+   *   The highest severity in the array.
+   */
+  public static function getMaxSeverity(array $requirements) {
+    return array_reduce($requirements, [__CLASS__, 'max'], RequirementInterface::SEVERITY_OK);
+  }
+
+  /**
+   * Finds the max severity for a requirement.
+   *
+   * @param int $severity
+   *   The severity.
+   * @param \Drupal\Core\Extension\Requirement\RequirementInterface $requirement
+   *   The requirement to compare.
+   *
+   * @return int
+   *   The severity.
+   */
+  protected static function max($severity, RequirementInterface $requirement) {
+    return max($severity, $requirement->getSeverity());
+  }
+
+}
diff --git a/core/modules/system/src/SystemManager.php b/core/modules/system/src/SystemManager.php
index 3fc41829c6..1dd2965b99 100644
--- a/core/modules/system/src/SystemManager.php
+++ b/core/modules/system/src/SystemManager.php
@@ -130,8 +130,11 @@ public function listRequirements() {
    *   An array of requirements, in the same format as is returned by
    *   hook_requirements().
    *
-   * @return
+   * @return int
    *   The highest severity in the array.
+   *
+   * @deprecated Will be removed in Drupal 9.0.0
+   * @see \Drupal\Core\Extension\Requirement\RequirementHelper::getMaxSeverity()
    */
   public function getMaxSeverity(&$requirements) {
     $severity = static::REQUIREMENT_OK;
diff --git a/core/tests/Drupal/Tests/Core/Extension/Requirement/RequirementHelperTest.php b/core/tests/Drupal/Tests/Core/Extension/Requirement/RequirementHelperTest.php
new file mode 100644
index 0000000000..99ffb1ed35
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Extension/Requirement/RequirementHelperTest.php
@@ -0,0 +1,73 @@
+<?php
+
+namespace Drupal\Tests\Core\Extension\Requirement;
+
+use Drupal\Core\Extension\Requirement\RequirementError;
+use Drupal\Core\Extension\Requirement\RequirementHelper;
+use Drupal\Core\Extension\Requirement\RequirementInfo;
+use Drupal\Core\Extension\Requirement\RequirementInterface;
+use Drupal\Core\Extension\Requirement\RequirementOk;
+use Drupal\Core\Extension\Requirement\RequirementWarning;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Extension\Requirement\RequirementHelper
+ *
+ * @group Extension
+ */
+class RequirementHelperTest extends UnitTestCase {
+
+  /**
+   * @covers ::getMaxSeverity
+   * @dataProvider requirementProvider
+   *
+   * @param RequirementInterface[] $requirements
+   * @param int $expectedSeverity
+   */
+  public function testGetMaxSeverity($requirements, $expectedSeverity) {
+    $severity = RequirementHelper::getMaxSeverity($requirements);
+    $this->assertEquals($expectedSeverity, $severity);
+  }
+
+  /**
+   * Data provider for requirement helper test.
+   *
+   * @return array
+   *   Test data.
+   */
+  public function requirementProvider() {
+    $info = RequirementInfo::create()
+      ->setValue("Foo");
+    $warning = RequirementWarning::create()
+      ->setValue("Baz");
+    $error = RequirementError::create()
+      ->setValue("Baz");
+    $ok = RequirementOk::create()
+      ->setValue("Bar");
+    return [
+      [
+        [
+          $info,
+          $error,
+          $ok,
+        ],
+        RequirementInterface::SEVERITY_ERROR,
+      ],
+      [
+        [
+          $info,
+          $ok,
+        ],
+        RequirementInterface::SEVERITY_OK,
+      ],
+      [
+        [
+          $warning,
+          $info,
+          $ok,
+        ],
+        RequirementInterface::SEVERITY_WARNING,
+      ],
+    ];
+  }
+}