diff --git a/core/modules/simpletest/src/Tests/BrokenSetUpTest.php b/core/modules/simpletest/src/Tests/BrokenSetUpTest.php
index 4067f79..ed75433 100644
--- a/core/modules/simpletest/src/Tests/BrokenSetUpTest.php
+++ b/core/modules/simpletest/src/Tests/BrokenSetUpTest.php
@@ -30,9 +30,9 @@ class BrokenSetUpTest extends WebTestBase {
   public static $modules = array('simpletest');
 
   /**
-   * The memory limit for this test, Testing module requires 128M.
+   * The memory limit for this test, the Simpletest UI is very expensive.
    */
-  protected $memoryUsageTrigger = 140;
+  protected $memoryUsageTrigger = FALSE;
 
   /**
    * The path to the shared trigger file.
diff --git a/core/modules/simpletest/src/Tests/InstallationProfileModuleTestsTest.php b/core/modules/simpletest/src/Tests/InstallationProfileModuleTestsTest.php
index a58d378..561d2f4 100644
--- a/core/modules/simpletest/src/Tests/InstallationProfileModuleTestsTest.php
+++ b/core/modules/simpletest/src/Tests/InstallationProfileModuleTestsTest.php
@@ -31,9 +31,9 @@ class InstallationProfileModuleTestsTest extends WebTestBase {
   protected $adminUser;
 
   /**
-   * The memory limit for this test, Testing module requires 128M.
+   * The memory limit for this test, the Simpletest UI is very expensive.
    */
-  protected $memoryUsageTrigger = 140;
+  protected $memoryUsageTrigger = FALSE;
 
   /**
    * Use the Testing profile.
diff --git a/core/modules/simpletest/src/Tests/MissingCheckedRequirementsTest.php b/core/modules/simpletest/src/Tests/MissingCheckedRequirementsTest.php
index 5f95148..f9364b3 100644
--- a/core/modules/simpletest/src/Tests/MissingCheckedRequirementsTest.php
+++ b/core/modules/simpletest/src/Tests/MissingCheckedRequirementsTest.php
@@ -24,9 +24,9 @@ class MissingCheckedRequirementsTest extends WebTestBase {
   public static $modules = array('simpletest');
 
   /**
-   * The memory limit for this test, Testing module requires 128M.
+   * The memory limit for this test, the Simpletest UI is very expensive.
    */
-  protected $memoryUsageTrigger = 140;
+  protected $memoryUsageTrigger = FALSE;
 
   protected function setUp() {
     parent::setUp();
diff --git a/core/modules/simpletest/src/Tests/OtherInstallationProfileTestsTest.php b/core/modules/simpletest/src/Tests/OtherInstallationProfileTestsTest.php
index d7be9ab..6d1c625 100644
--- a/core/modules/simpletest/src/Tests/OtherInstallationProfileTestsTest.php
+++ b/core/modules/simpletest/src/Tests/OtherInstallationProfileTestsTest.php
@@ -39,9 +39,9 @@ class OtherInstallationProfileTestsTest extends WebTestBase {
   protected $profile = 'minimal';
 
   /**
-   * The memory limit for this test, Testing module requires 128M.
+   * The memory limit for this test, the Simpletest UI is very expensive.
    */
-  protected $memoryUsageTrigger = 140;
+  protected $memoryUsageTrigger = FALSE;
 
   /**
    * An administrative user with permission to administer unit tests.
diff --git a/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php b/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php
index 94aefa2..80c4032 100644
--- a/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php
+++ b/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php
@@ -25,9 +25,9 @@ class SimpleTestBrowserTest extends WebTestBase {
   public static $modules = array('simpletest', 'test_page_test');
 
   /**
-   * The memory limit for this test, Testing module requires 128M.
+   * The memory limit for this test, the Simpletest UI is very expensive.
    */
-  protected $memoryUsageTrigger = 140;
+  protected $memoryUsageTrigger = FALSE;
 
   public function setUp() {
     parent::setUp();
diff --git a/core/modules/simpletest/src/Tests/SimpleTestTest.php b/core/modules/simpletest/src/Tests/SimpleTestTest.php
index 85b8187..6b4d076 100644
--- a/core/modules/simpletest/src/Tests/SimpleTestTest.php
+++ b/core/modules/simpletest/src/Tests/SimpleTestTest.php
@@ -27,9 +27,9 @@ class SimpleTestTest extends WebTestBase {
   public static $modules = array('simpletest', 'test_page_test');
 
   /**
-   * The memory limit for this test, Testing module requires 128M.
+   * The memory limit for this test, the Simpletest UI is very expensive.
    */
-  protected $memoryUsageTrigger = 140;
+  protected $memoryUsageTrigger = FALSE;
 
   /**
    * The results array that has been parsed by getTestResults().
diff --git a/core/modules/simpletest/src/WebTestBase.php b/core/modules/simpletest/src/WebTestBase.php
index 6d5299a..44ce470 100644
--- a/core/modules/simpletest/src/WebTestBase.php
+++ b/core/modules/simpletest/src/WebTestBase.php
@@ -64,7 +64,14 @@
   /**
    * Set to the maximum number of MB of memory usage to allow on the child site.
    *
-   * @var int
+   * The minimum about of memory Drupal expects is defined by
+   * DRUPAL_MINIMUM_PHP_MEMORY_LIMIT. This value should either by equal or less
+   * to conform to this requirement. If a module requires more memory than the
+   * module should add a check to its hook_requirements and use the higher value
+   * in it's tests. The check can be disabled for a specific tests by setting it
+   * to FALSE.
+   *
+   * @var int|FALSE
    */
   protected $memoryUsageTrigger = 64;