diff --git a/packages/core/src/render3/i18n.ts b/packages/core/src/render3/i18n.ts
index 6c0c5ec7b1..1377482c80 100644
--- a/packages/core/src/render3/i18n.ts
+++ b/packages/core/src/render3/i18n.ts
@@ -9,7 +9,7 @@ import '../util/ng_i18n_closure_mode';
 
 import {DEFAULT_LOCALE_ID, getPluralCase} from '../i18n/localization';
 import {getTemplateContent, SRCSET_ATTRS, URI_ATTRS, VALID_ATTRS, VALID_ELEMENTS} from '../sanitization/html_sanitizer';
-import {InertBodyHelper} from '../sanitization/inert_body';
+import {getInertBodyHelper} from '../sanitization/inert_body';
 import {_sanitizeUrl, sanitizeSrcset} from '../sanitization/url_sanitizer';
 import {addAllToArray} from '../util/array_utils';
 import {assertDataInRange, assertDefined, assertEqual} from '../util/assert';
@@ -1233,7 +1233,7 @@ function icuStart(
 function parseIcuCase(
     unsafeHtml: string, parentIndex: number, nestedIcus: IcuExpression[], tIcus: TIcu[],
     expandoStartIndex: number): IcuCase {
-  const inertBodyHelper = new InertBodyHelper(getDocument());
+  const inertBodyHelper = getInertBodyHelper(getDocument());
   const inertBodyElement = inertBodyHelper.getInertBodyElement(unsafeHtml);
   if (!inertBodyElement) {
     throw new Error('Unable to generate inert body element');
diff --git a/packages/core/src/sanitization/html_sanitizer.ts b/packages/core/src/sanitization/html_sanitizer.ts
index 4f79d98927..ab7bbbe836 100644
--- a/packages/core/src/sanitization/html_sanitizer.ts
+++ b/packages/core/src/sanitization/html_sanitizer.ts
@@ -7,7 +7,7 @@
  */
 
 import {isDevMode} from '../util/is_dev_mode';
-import {InertBodyHelper} from './inert_body';
+import {getInertBodyHelper, InertBodyHelper} from './inert_body';
 import {_sanitizeUrl, sanitizeSrcset} from './url_sanitizer';
 
 function tagSet(tags: string): {[k: string]: boolean} {
@@ -245,7 +245,7 @@ let inertBodyHelper: InertBodyHelper;
 export function _sanitizeHtml(defaultDoc: any, unsafeHtmlInput: string): string {
   let inertBodyElement: HTMLElement|null = null;
   try {
-    inertBodyHelper = inertBodyHelper || new InertBodyHelper(defaultDoc);
+    inertBodyHelper = inertBodyHelper || getInertBodyHelper(defaultDoc);
     // Make sure unsafeHtml is actually a string (TypeScript types are not enforced at runtime).
     let unsafeHtml = unsafeHtmlInput ? String(unsafeHtmlInput) : '';
     inertBodyElement = inertBodyHelper.getInertBodyElement(unsafeHtml);
diff --git a/packages/core/src/sanitization/inert_body.ts b/packages/core/src/sanitization/inert_body.ts
index e859f8af5a..9e3530be71 100644
--- a/packages/core/src/sanitization/inert_body.ts
+++ b/packages/core/src/sanitization/inert_body.ts
@@ -7,40 +7,29 @@
  */
 
 /**
- * This helper class is used to get hold of an inert tree of DOM elements containing dirty HTML
+ * This helper is used to get hold of an inert tree of DOM elements containing dirty HTML
  * that needs sanitizing.
  * Depending upon browser support we use one of two strategies for doing this.
- * Default: DomParser strategy
+ * Default: DOMParser strategy
  * Fallback: InertDocument strategy
  */
-export class InertBodyHelper {
-  private inertDocument: Document;
-
-  constructor(private defaultDoc: Document) {
-    this.inertDocument = this.defaultDoc.implementation.createHTMLDocument('sanitization-inert');
-    if (this.inertDocument.body == null) {
-      // usually there should be only one body element in the document, but IE doesn't have any, so
-      // we need to create one.
-      const inertHtml = this.inertDocument.createElement('html');
-      this.inertDocument.appendChild(inertHtml);
-      const inertBodyElement = this.inertDocument.createElement('body');
-      inertHtml.appendChild(inertBodyElement);
-    }
-
-    this.getInertBodyElement = isDOMParserAvailable() ? this.getInertBodyElement_DOMParser :
-                                                        this.getInertBodyElement_InertDocument;
-  }
+export function getInertBodyHelper(defaultDoc: Document): InertBodyHelper {
+  return isDOMParserAvailable() ? new DOMParserHelper() : new InertDocumentHelper(defaultDoc);
+}
 
+export interface InertBodyHelper {
   /**
    * Get an inert DOM element containing DOM created from the dirty HTML string provided.
-   * The implementation of this is determined in the constructor, when the class is instantiated.
    */
   getInertBodyElement: (html: string) => HTMLElement | null;
+}
 
-  /**
-   * Use DOMParser to create and fill an inert body element in browsers that support it.
-   */
-  private getInertBodyElement_DOMParser(html: string) {
+/**
+ * Uses DOMParser to create and fill an inert body element.
+ * This is the default strategy used in browsers that support it.
+ */
+class DOMParserHelper implements InertBodyHelper {
+  getInertBodyElement(html: string): HTMLElement|null {
     // We add these extra elements to ensure that the rest of the content is parsed as expected
     // e.g. leading whitespace is maintained and tags like `<meta>` do not get hoisted to the
     // `<head>` tag.
@@ -54,13 +43,30 @@ export class InertBodyHelper {
       return null;
     }
   }
+}
 
-  /**
-   * Use an HTML5 `template` element, if supported, or an inert body element created via
-   * `createHtmlDocument` to create and fill an inert DOM element.
-   * This is the fallback strategy if the browser does not support DOMParser.
-   */
-  private getInertBodyElement_InertDocument(html: string) {
+/**
+ * Use an HTML5 `template` element, if supported, or an inert body element created via
+ * `createHtmlDocument` to create and fill an inert DOM element.
+ * This is the fallback strategy if the browser does not support DOMParser.
+ */
+class InertDocumentHelper implements InertBodyHelper {
+  private inertDocument: Document;
+
+  constructor(private defaultDoc: Document) {
+    this.inertDocument = this.defaultDoc.implementation.createHTMLDocument('sanitization-inert');
+
+    if (this.inertDocument.body == null) {
+      // usually there should be only one body element in the document, but IE doesn't have any, so
+      // we need to create one.
+      const inertHtml = this.inertDocument.createElement('html');
+      this.inertDocument.appendChild(inertHtml);
+      const inertBodyElement = this.inertDocument.createElement('body');
+      inertHtml.appendChild(inertBodyElement);
+    }
+  }
+
+  getInertBodyElement(html: string): HTMLElement|null {
     // Prefer using <template> element if supported.
     const templateEl = this.inertDocument.createElement('template');
     if ('content' in templateEl) {