Ms. Chandanie J. Gunathilake
IPS Corporation
500 Distribution Parkway
Collierville, TN 38017

RE: The tariff classification of a water hammer arrestor from Taiwan

Dear Ms. Gunathilake:

In your letter dated July14, 2022, you requested a tariff classification ruling. Product descriptions and photographs of the water hammer arrestor were provided for our review.

The article under consideration is identified as the 3/4" FHT Washing Machine Water Hammer Arrestor AA, IPS Item Number 92311 (Model Number ML11052). The subject article is described as a “Copper/brass with plastic/rubber piston inside that absorbs shock wave caused by water hammer.” Each water hammer arrestor consists of a brass shell/chamber, a plastic sliding piston, rubber gaskets, a brass body, and a brass inner hex joint. The article measures ¾ inch in length by ¾ inch in width. Based on the documents provided, the brass components comprise 85 percent of the weight and 78 percent of the value of the water hammer arrestor. You stated that the subject arrestor will “eliminate water hammer in residential and light commercial supply lines by absorbing sudden pressure changes due to fast closing shutoff valves and clothes washers. This action protects/keeps the pipes from banging and the potentially damaging effects of water hammer… The arrestor needs to be installed in areas where faucets and valves are creating noise. The installation usually requires cutting pipes, inserting tees, and then installing the water hammer arrestor.”

The Washing Machine Water Hammer Arrestor is comprised of copper/brass, plastic, and nitrile butadiene rubber (NBR) components that are classified in different headings. Classification of merchandise under the Harmonized Tariff Schedule of the United States (HTSUS) is in accordance with the General Rules of Interpretation (GRIs), taken in order.  GRI 1 provides that classification shall be determined according to the terms of the headings and any relative section or chapter notes.  Since no one heading in the tariff schedules covers the components of the water hammer arrestor in combination, GRI 1 cannot be used as a basis for classification.  GRI 3(b) provides that mixtures, composite goods consisting of different materials or made up of different components, and goods put up in sets for retail sale shall be classified as if they consisted of the material or component which gives them their essential character.  

As the subject water hammer arrestor is a composite good, we must apply rule GRI 3(b), which provides that composite goods are to be classified according to the component that gives the goods their essential character. EN VIII to GRI 3(b) explains that “the factor which determines essential character will vary as between different kinds of goods. It may, for example be determined by the nature of the material or component, its bulk, quantity, weight or the use of the goods.” We must determine whether the brass components, the plastic components or the rubber components impart the essential character to the subject water hammer arrestor. It is the role of the constituent materials or components in relation to the use of the good that imparts the essential character. In this case, the brass shell/chamber, the brass body and brass inner hex joint provide the vast majority of the bulk to the water hammer arrestor. Also, based on the breakdown of materials by value, the brass predominates by value over the plastic and the rubber. Therefore, it is the opinion of this office that the brass imparts the essential character to the composite article. In accordance with GRI 3(b), the Washing Machine Water Hammer Arrestor will be classified under heading 7419, HTSUS, which provides for other articles of copper. The applicable subheading for the 3/4" FHT Washing Machine Water Hammer Arrestor AA, IPS Item Number 92311 (Model Number ML11052), will be 7419.80.5010, HTSUS, which provides for other articles of copper, other…brass plumbing goods not elsewhere specified or included. The rate of duty will be free.

Duty rates are provided for your convenience and are subject to change. The text of the most recent HTSUS and the accompanying duty rates are provided at

This ruling is being issued under the provisions of Part 177 of the Customs Regulations (19 C.F.R. 177).

A copy of the ruling or the control number indicated above should be provided with the entry documents filed at the time this merchandise is imported. If you have any questions regarding the ruling, contact National Import Specialist Ann Taub at [email protected].


Steven A. Mack
National Commodity Specialist Division