Glendale City Code 33-92: backflow devices on fire sprinkler services

Section 33-92 has three parts. Subsection (a): when a backflow device is required on a service that supplies only a fire sprinkler system, it is installed at the service connection to the city's standard specification. Subsection (b): if the city decides the sprinkler system needs continuous water that "may not be interrupted during testing of the backflow prevention device," the customer installs two devices in parallel at the customer's expense, each with a diameter at least equal to the service connection. Subsection (c): "Modifications of an existing service connection supplying water solely to a fire sprinkler system shall require the entire system to comply with the requirements of Section 33-18 and Section 33-90."

Section 33-90 decides which device. Fire systems in AWWA classes 1, 2 and 3 need a double check assembly. That also applies to any fire system 6 inches or larger, or built of piping not approved for potable water use. Classes 4, 5 and 6 need a reduced pressure assembly. If the same premises has an industrial or domestic service that needs protection, both services get protection for the highest hazard of either system.

Section 33-96(b) adds a limit: water service to a fire sprinkler system is not disconnected under the backflow shutoff rules. The city can still cite a misdemeanor if a required fix is ignored past the notice.

• Fire sprinkler service: a water connection that supplies only the sprinkler system, as opposed to a combined fire and domestic line.
• AWWA classes: a classification of fire systems used in the 33-90 list. Glendale's code cites the classes without defining them, so ask your fire protection contractor which class your system is.
• Parallel devices: two assemblies side by side so one can be tested while the other keeps water flowing.

Buildings with a fire sprinkler system on a Glendale water service. It does not cover the sprinkler design itself, which follows the fire code. It also does not cover a fire service the city has not required a device on.

A retail center upsizes or replaces its fire service. Subsection (c) applies to "Modifications of an existing service connection", so a new or upsized fire service is the kind of change to raise with the city. Whether sprinkler work inside a tenant suite counts is not something the section says, so ask Cross Connection Control before assuming either way.

A building whose sprinkler class is unclear. The 33-90 list gives a double check for classes 1 to 3 and a reduced pressure assembly for classes 4 to 6. The wrong class means the wrong device on the plans, so get the class in writing from the fire protection contractor first.

The edge case: an overdue test on a fire line. For a domestic line the city can shut off water after notices. For a fire-only service it cannot use disconnection, so the enforcement path is the misdemeanor citation instead.

1. 1Have your fire protection contractor state the AWWA class of the system and the pipe size.
2. 2Match it to the 33-90 device: double check for classes 1 to 3, reduced pressure for classes 4 to 6.
3. 3Ask Glendale Water Services Cross Connection Control (623-930-4138) whether the city wants a parallel pair for continuous water.
4. 4Show the device on the plans. Section 33-99 requires city approval before the permit.
5. 5After installation, request inspection at the permit line, 623-915-3263, code 238 for a backflow fire line.
6. 6Schedule the yearly test with a city-certified tester.

• "A fire line is exempt from backflow rules." It is not. It is exempt only from the water shutoff remedy.
• "A small change is just a small change." Modifying a fire-only service triggers compliance for the entire system under 33-92(c).
• "One device is always enough." The city can require two in parallel when water must not be interrupted.

The rules are Glendale City Code Secs. 33-90, 33-92 and 33-96 on Municode. This is a summary of three short sections. The code text and the fire department's requirements control your project.