Tempe IPC 608.7.2: which facilities need a secondary backflow assembly?

The model IPC has a section 608.7.2. Tempe replaced it with its own text: "The following activities or facilities shall have a Secondary Reduced Pressure Principle Backflow Prevention assembly installed as close as practicable to each point of service delivery: Hospitals, surgical clinics, medical buildings, laboratories, morgues, mortuaries, veterinary hospitals, animal grooming shops, industrial occupancies, packing plants, slaughter houses, chemical plants, municipal waste treatment facilities, auxiliary water systems, construction water services or as otherwise required by the City of Tempe Building Official."

A note follows: "Multiple water services which are interconnected onsite shall be provided with not less than a Double Check Valve Assembly at each service connection."

The parts:

• Who: the named facilities, plus anything the Building Official adds.
• What: a reduced pressure principle (RP) assembly.
• Where: as close as practicable to each point of service delivery, which means every service, not just the main one.
• Interconnected services: at least a double check at each, even if the facility is not on the list.

• Secondary: the code does not define it. Our reading is that it means protection at the service connection, over and above any protection built into the building's own equipment.
• Point of service delivery: where city water enters the property, usually the meter.
• Industrial occupancy: not defined in this section. It is a building-code classification, so the plans examiner decides.
• Auxiliary water system: a second water source on the property, such as a well or reclaimed line.
• Interconnected: two services tied together inside the property.

It covers new and altered buildings of the listed types and construction water services, which are temporary services for building sites. It does not cover a house or a facility not on the list, unless the Building Official adds it or another rule applies. The water code in 33-105 has its own overlapping table, and the stricter answer wins.

A new outpatient clinic. Medical buildings and surgical clinics are named, so the plans need an RP at the point where each service enters.

A warehouse with two water services. Neither service is on the list, but the owner tied them together inside for fire and domestic supply. The note applies: a double check at each connection at minimum.

The edge case: a restaurant. The list does not name it, and the section leaves room for the Building Official to add facilities. Tempe's water code, 33-105, does not name restaurants either. Ask plan review before you assume it is exempt.

1. 1Compare your occupancy with the list above and with the 33-105 table.
2. 2Put an RP on the plans at each point of service delivery, with the location marked.
3. 3Keep it above ground. IPC 608.8.1 bars backflow devices in pits, underground vaults or submerged locations.
4. 4The designer or contractor submits the plans with the building permit application to Tempe Building Safety (480-350-8341 is the permit number on the city's Backflow FAQ). The water code requires approval before the permit issues.
5. 5After installation, have the assembly tested and inspected before the certificate of occupancy.
6. 6Plan for a test every year after that.

• "Secondary means optional." The code says these facilities "shall have" the assembly.
• "The meter has a check valve, so I am covered." The code calls for a reduced pressure assembly, not a meter check.
• "One assembly at the main covers everything." The requirement is at each point of service delivery.
• "Tempe and Phoenix use the same list." They overlap, but veterinary hospitals, animal grooming shops, industrial occupancies and packing plants are on Tempe's list only. Phoenix sends the rest to its own Chapter 37, Article XII.