7.3 Applying Backflow Protection to Specific Connections

Connections to the potable water system — IPC 608.17

This section is essentially a lookup table in prose. Exam items pick a connection and ask which device is required.

Two sprinkler exceptions worth knowing

IPC 608.17.4 exceptions:

1. Where systems are installed as a portion of the water distribution system in accordance with the code and are not provided with a fire department connection, isolation of the water supply system is not required. This is the multipurpose residential sprinkler case covered in Chapter 17 of this guide.
2. Isolation is not required for deluge, preaction or dry pipe systems.

Hose connections — IPC 608.16.4.2

Sillcocks, hose bibbs, wall hydrants and other openings with a hose connection shall be protected by an atmospheric-type or pressure-type vacuum breaker or a permanently attached hose connection vacuum breaker.

Two exceptions:

1. Water heater and boiler drain valves provided with hose connection threads and intended only for tank or vessel draining.
2. Water supply valves intended for connection of clothes washing machines where backflow prevention is otherwise provided or is integral with the machine.

The reason hose connections get their own rule is that IPC 608.16.1 expressly bars protecting hose-connection outlets by air gap. You cannot maintain a gap at the end of a hose.

Health care applications — IPC 608.3.1 and Section 609

Health care creates the highest-hazard connections in ordinary plumbing:

• 608.3.1: hospital fixture water supplies protected by an RPZ, an atmospheric or spill-resistant vacuum breaker assembly, or an air gap. Vacuum breakers for bedpan washer hoses shall not be located less than 5 feet above the floor. Vacuum breakers for hose connections in health care or laboratory areas shall be not less than 6 feet above the floor.
• 609.4 Vacuum breaker installation: vacuum breakers in health care serving bedpan washers, aspirators, sterilizers and similar equipment must be installed at the required heights with access.
• 609.5: jet- or water-supplied orifices, except those supplied by the flush connections, shall not be located in or connected with a water closet bowl or clinical sink. The section does not prohibit an approved bidet installation.
• 609.6: clinical, hydrotherapeutic and radiological equipment supplies must be protected against backflow.
• 609.7 Condensate drain trap seal: condensate drains serving health care equipment must maintain a trap seal.
• 609.8 Valve leakage diverter: required where a leaking valve could contaminate a sterile field.

Colorado field note (not exam-scored): Board Rule 1.2(E)(1)(dd) restates 608.3.1 with the same 5-foot and 6-foot vacuum breaker heights and adds dental chairs alongside hospital fixtures.

Disinfection — IPC Section 610

New potable water systems shall be purged of deleterious matter and disinfected prior to utilization. The method is the one prescribed by the health authority or water purveyor having jurisdiction, or in the absence of a prescribed method, AWWA C651 or AWWA C652, or the procedure in Section 610 itself:

1. Flush the system with clean, potable water until dirty water does not appear at outlets.
2. Apply the approved disinfection method — either:
   • fill with a solution of 50 parts per million (ppm) of chlorine and hold for 24 hours, or
   • fill with a solution of 200 ppm chlorine and hold for 3 hours.
3. Flush with clean potable water until the chlorine is purged from the system.
4. Repeat the procedure where a bacteriological examination shows contamination remains.

Learn the pair as a trade-off: lower concentration, longer contact (50 ppm / 24 hours) or higher concentration, shorter contact (200 ppm / 3 hours).

IPC 602.3.4 requires the same disinfection for a newly constructed individual water supply system.

Testing and inspection, restated

From Chapter 2 of this guide, because it belongs to this topic as well:

• IPC 312.10.1: annual inspections of all backflow prevention assemblies and air gaps to determine whether assemblies are operable and air gaps exist.
• IPC 312.10.2: RP, DC, PVB, RP detector fire protection, DC detector fire protection and SVB assemblies, plus hose connection backflow preventers, are tested at installation, immediately after repairs or relocation, and at least annually, per ASSE 5013, 5015, 5020, 5047, 5048, 5052, 5056, CSA B64.10 or B64.10.1, with test gauges complying with ASSE 1064.

The inspection duty is broader than the testing duty. Air gaps cannot be "tested," but they must be inspected annually to confirm they still exist — the single most common finding being a hose or extension added below a gap that was correct at installation.