Can a Water Hammer Arrester be placed at the top of a riser and be effective?
No. The location of the unit itself is essential for proper operation and effectiveness. Usually, the top of the riser is so remote to the source of the problem, the unit never has an opportunity to perform its job. The location should be at the piping serving the fixture(s) and normally between the last two fixtures. Refer to the Smith ‘Yellow Pages’ catalog, Water Hammer Arrester section for complete information on sizing, placement and selection. The Plumbing & Drainage Institute (PDI) Water Hammer Arrester Standard, WH-201, may also be referred to for sizing, placement and selection.
