ASSE 5130 cheat sheet

Cross-connection: any actual or potential connection between a potable water system and a source of contamination or pollution; backflow is the unwanted reversal of flow into potable supply.

Backsiphonage is caused by negative or sub-atmospheric pressure in the supply; backpressure is caused by downstream pressure exceeding supply pressure (pumps, boilers, elevation, compressed gas).

Pollution is a substance that degrades water quality but does not create a health hazard; contamination creates an actual health hazard, so contaminant protection requires a higher degree of protection.

Degree of hazard drives the required protection: health hazard (toxic or biological) requires an air gap or reduced pressure principle assembly; non-health hazard permits a double check or atmospheric vacuum breaker depending on application.

Authority hierarchy: federal Safe Drinking Water Act sets the floor; state primacy agencies adopt rules; local water purveyors enforce containment through ordinance, plumbing code, and cross-connection control programs.

Typical program elements: enabling ordinance, hazard survey, containment versus isolation protection, assembly approval lists, tester certification, and annual testing with records retained per jurisdiction.

Premises isolation (containment) protects the public main at the service; internal isolation protects fixtures and processes; a complete program generally uses both, since containment alone does not protect occupants.

Cross-connections are controlled by elimination, by an approved air gap, or by a mechanical backflow preventer; no assembly may be substituted for an air gap where an air gap is specifically required.

Definitions that appear on exams: cross-connection, backflow, backsiphonage, backpressure, pollution, contamination, air gap, backflow preventer, containment, and auxiliary supply.

Air gap: physical separation of at least twice the effective opening diameter, never less than 1 inch; highest protection, appropriate for health hazards and high-hazard connections.

Atmospheric vacuum breaker (AVB): non-testable, no downstream shutoff valve, must be installed at least 6 inches above the highest downstream outlet; used on hose bibbs and irrigation zones.

Pressure vacuum breaker (PVB): testable, with a loaded check and an air inlet; must be installed 12 inches above the highest downstream outlet and may have downstream shutoff valves.

Double check valve assembly (DCVA): two check valves, testable, for non-health hazards such as low-hazard commercial and irrigation service lines.

Reduced pressure principle assembly (RPZ): two check valves plus a hydraulically loaded relief valve; the only mechanical assembly approved for health hazards, and it must not be installed in a pit or submerged location.

Spill-resistant vacuum breaker (SVB): a PVB variant with a check that limits discharge at the air inlet; used where a PVB would discharge in normal operation, and it is testable.

Specialty devices: dual check (non-testable, residential service), hose connection vacuum breaker, and barometric loop (not a mechanical device, limited to backsiphonage only).

Selection rules: health hazard requires an air gap or RPZ; continuous pressure requires a testable device with loaded checks; non-health hazard permits DCVA or PVB depending on backsiphonage risk.

Assembly versus device: an assembly is testable and has two or more shutoff valves and test cocks; a device is not testable and does not meet assembly requirements.

Test equipment: differential pressure gauge, test kit hoses, and test cock adapters; gauge must be calibrated and its accuracy verified before use, with calibration records retained.

Gauge accuracy is commonly required within plus or minus 2 percent of full scale or a stated psi tolerance; a gauge out of tolerance invalidates the field test.

Test sequence for an RPZ: record supply pressure, test check valve 1 (RPZ), test check valve 2, then test the relief valve differential, then verify the relief opens at the required threshold.

RPZ relief valve opening point is typically required to open at 2 psi or greater differential; a relief valve that opens below the threshold indicates a failed check or relief valve.

Test sequence for a DCVA: test check 1 for tightness, then check 2, using the gauge in series with the test cocks and observing pressure drop or hold.

PVB test: verify check valve tightness and verify the air inlet opens at the required vacuum; AVB is not field tested but is inspected for installation height and absence of downstream shutoff.

Backsiphonage test: the gauge is used to create a negative pressure by bleeding water through the high side, then observing whether the check holds.

Test report content: assembly make, model, size, serial number, location, test date, tester name and certification number, gauge serial number and calibration date, and pass or fail with values recorded.

A failed test requires notification to the water purveyor, repair or replacement, and retest; the assembly is not returned to service until it passes.

Continuous relief discharge on an RPZ usually means a fouled or damaged first check, debris on the relief seat, or a failed relief diaphragm; inspect check 1 before replacing the relief valve.

RPZ relief valve opens at too low a differential when check 1 is leaking, the relief spring is weak, or the relief seat is damaged.

Chatter or noise in a check valve indicates a worn spring, damaged seat, or debris; disassemble and inspect rather than adjusting the relief setting.

Water passing a check valve can be caused by debris on the seat, a torn seat disc, a broken spring, or a distorted clapper; repair kits restore original performance.

Air inlet on a PVB that leaks continuously can indicate a fouled air inlet seat, a failed check, or water pressure reaching the air inlet due to a downstream shutoff installed too low.

Repair parts must be manufacturer-approved; field modifications, mismatched parts, and altered springs void approval and can change the assembly's rated protection.

Maintenance intervals: annual testing is the minimum in most programs; high-use or dirty-water installations may require more frequent inspection, and strainers should be cleaned at service.

After any repair, the assembly must be retested and the results reported; record the repair, parts used, tester, and date for traceability.

Freeze damage, water hammer, and debris are the most common causes of failure; protection includes draining, proper orientation, and strainer maintenance.

RPZ installation: must be installed horizontally unless the manufacturer lists vertical approval, with adequate clearance for testing and repair, and must not be in a pit, vault, or location subject to flooding or backpressure.

RPZ discharge: relief valve discharge must be piped to a drain with an air gap and must not be connected directly to a drainage system; the discharge must be visible.

PVB and AVB installation height: PVB at least 12 inches above the highest downstream outlet; AVB at least 6 inches above the highest downstream outlet and no downstream shutoff.

Air gap: minimum separation of twice the effective opening diameter and never less than 1 inch, measured from the supply pipe to the flood level rim of the receiving fixture.

Site survey steps: identify all water uses and auxiliary supplies, trace the distribution system, list cross-connections, assign degree of hazard, and specify protection for each.

Containment survey: locate the service connection, meter, and any bypass; verify no unprotected bypass, no fire line connection without protection, and no unauthorized auxiliary supply.

Auxiliary supplies such as wells, reclaimed water, boilers, and chemical injection systems require an air gap or RPZ at the point of connection; a DCVA is not acceptable for a health hazard.

Installation records: as-built drawings, device location, orientation, size, and manufacturer approval documentation should be retained for the assembly's service life.

Retain test and repair reports per jurisdiction; many programs require records for at least 3 to 5 years, and some require the life of the assembly.

Required report fields: assembly identification, location, size, make, model, serial number, test values, pass or fail, tester certification, gauge calibration, and date.

Tester certification: certification must be current and issued by a recognized program; testing performed with an expired certification is generally not accepted.

Gauge calibration records must be traceable and available at the time of test; a gauge without current calibration invalidates the reported results.

Safety hazards in the field: confined spaces (vaults, pits), electrical hazards, slips and falls, and pressure release; never enter a permit-required confined space without training, attendant, and atmospheric testing.

Pressure safety: depressurize and bleed test cocks slowly, wear eye protection, and never loosen fittings on a pressurized assembly.

Contamination control: use dedicated hoses and disinfect test connections; do not allow test water to contact the potable supply, and flush the assembly after testing.

Notification requirements: report failed assemblies to the purveyor and owner promptly, and document the corrective action taken and the retest result.

Record retention supports audits, liability defense, and program compliance; electronic records must be secure, backed up, and retrievable.