System Testing

System Testing

Reference text for the system testing area. Every rule below is stated from a printed line of the

2024 International Plumbing Code (IPC 2024) that carries it, or from a line of the Georgia rule that

110-11-1-.26 prints beside it, and the address of the line is given with the rule. Numbers appear

only where the printed line carries them.

The tests a plumbing system must pass are gathered in one place in this code: Section 312, « Tests and

Inspections », in the general regulations chapter (IPC 2024, Chapter 3). The subject of the section is

what the permit holder owes: the applicable tests prescribed in Sections 312.2 through 312.11 are to be

made to determine compliance with the code (IPC 2024, 312.1). Around that section stand the

inspections the code official makes and the way a failed test is handled — and in Georgia one of the

two framing chapters is not part of the adopted code, which is stated where it bears on the tests

below (Section 8 of this text).

1. Who tests, with what, and when

The duty is on the permit holder, not on the inspector and not on the owner: the permit holder makes

the applicable tests to determine compliance, gives the code official reasonable advance notice when

the plumbing work is ready for tests, and furnishes the equipment, material, power and labour necessary

for the inspection and test, being responsible for determining that the work will withstand the test

pressure (IPC 2024, 312.1). The equipment, material and labour for testing a system or part of one are

furnished by the permit holder (IPC 2024, 111.4.2).

The medium is chosen by the code and not by preference: plumbing system piping is tested with either

water or, for piping systems other than plastic, with air (IPC 2024, 312.1). The test pressure itself

must be readable on the gauge, and the gauge is matched to the pressure: a test requiring 10 pounds per

square inch (69 kPa) or less uses a gauge with increments of 0.10 psi (0.69 kPa) or less; a test above

10 psi but not more than 100 psi uses increments of 1 psi (6.9 kPa) or less; and a test above 100 psi

uses increments of 2 psi (14 kPa) or less (IPC 2024, 312.1.1).

Two moments are fixed by the code. Fixtures are set and their traps filled with water before the entire

drainage system is submitted to the final tests (IPC 2024, 312.1), and new systems and parts of existing

systems that have been altered, extended or repaired are tested to disclose leaks and defects, with the

printed exceptions for work that adds to, replaces, alters or relocates no water supply, drainage or

vent piping, and for plumbing equipment set up temporarily for exhibition purposes (IPC 2024, 111.4.1).

Where work fails an initial test or inspection, the corrections are made and the work is resubmitted to

the code official for inspection and testing (IPC 2024, 111.4.3).

2. Testing the drainage and vent system

Four methods are printed for the drainage and vent system, and each carries its own holding time.

The water test is applied to the drainage system either in its entirety or in sections. Applied to the

whole system, all openings except the highest are tightly closed and the system is filled with water to

the point of overflow. Applied to sections, each opening except the highest openings of the section is

tightly plugged and each section is filled with water, but no section is tested with less than a

10-foot (3048 mm) head of water; in testing successive sections the upper 10 feet (3048 mm) of the

preceding section is tested again, so that no joint or pipe in the building except the uppermost 10

feet has been submitted to a test of less than that head. The pressure is held for not less than 15

minutes, after which the system must be tight at all points (IPC 2024, 312.2).

The air test has a printed prohibition and a printed pressure. Plastic piping is not to be tested using

air. Air is forced into the system until there is a uniform gauge pressure of 5 psi (34.5 kPa) or

sufficient to balance a 10-inch (254 mm) column of mercury, and that pressure is held for a test period

of not less than 15 minutes; adjustments to the test pressure needed because of changes in ambient

temperature or the seating of gaskets are made before the test period begins (IPC 2024, 312.3).

The vacuum test evacuates the portion under test with a vacuum-type pump to a uniform gauge pressure of

negative 5 pounds per square inch, or a negative 10 inches of mercury column (−34 kPa), holds that

pressure without removing additional air for 15 minutes, and takes the same temperature and gasket

adjustments before the period begins (IPC 2024, 312.4).

The final test is the one made after the fixtures are set: it is visual and detailed enough to

determine compliance. Where a smoke test is used instead, all traps are filled with water and a

pungent, thick smoke is introduced into the entire system from one or more smoke machines; when the

smoke appears at the stack openings on the roof those openings are closed and a pressure equivalent to

a 1-inch water column (248.8 Pa) is held for not less than 15 minutes (IPC 2024, 312.5).

Three chapters send their own testing to that section rather than restating it: the sanitary drainage

system is tested in accordance with Section 312 (IPC 2024, 701.6), the vent system is tested in

accordance with Section 312 (IPC 2024, 901.5), and the storm drainage conductors and building storm

drain are tested in accordance with Section 312 (IPC 2024, 1101.4).

3. Testing the building sewer

The sewer is tested on its own terms, and the difference between the two tests is the medium. A gravity

sewer test plugs the end of the building sewer at the point of connection with the public sewer, fills

the building sewer with water, tests it with not less than a 10-foot (3048 mm) head of water and

maintains that pressure for 15 minutes (IPC 2024, 312.7). A forced sewer test plugs the same end and

applies a pressure of 5 psi (34.5 kPa) greater than the pump rating, maintaining it for 15 minutes

(IPC 2024, 312.8). The same section applies to storm drainage inside a building, which is tested by

water or air in accordance with the drainage water test or the drainage air test (IPC 2024, 312.9).

4. Testing the water supply system

The water supply system has one test with two permitted media. On completion of a section of or the

entire water supply system, the part completed is tested and proved tight under a water pressure not

less than the working pressure of the system or, for piping systems other than plastic, by an air test

of not less than 50 psi (344 kPa); the pressure is held for not less than 15 minutes, and the water used

for tests is obtained from a potable source of supply (IPC 2024, 312.6). The two chapters that own water

distribution point at that section rather than repeating it: the potable water distribution system is

tested in accordance with Section 312.6 (IPC 2024, 601.4), and the water supply system test performed

at the end of the installation chapter is likewise performed in accordance with Section 312 (IPC 2024,

606.6).

5. Testing a shower liner

Where a shower floor or receptor is made watertight by a lining material, the completed liner

installation is tested, and the test is a depth and a time. The pipe from the shower drain is plugged

watertight, the floor and receptor area is filled with potable water to a depth of not less than 2

inches (51 mm) measured at the threshold, a temporary threshold being built where none 2 inches (51 mm)

high or greater exists, and the water is retained for not less than 15 minutes with no evidence of

leakage (IPC 2024, 312.10). The lining itself is recessed and fastened to an approved backing, turns up

on all sides not less than 2 inches (51 mm) above the finished threshold level, and is pitched one-fourth

unit vertical in 12 units horizontal toward the fixture drain, securely fastened to the waste outlet at

the seepage entrance; that section closes by sending the completed liner to the test above (IPC 2024,

421.5.2).

6. Inspection and testing of backflow prevention assemblies

Backflow prevention assemblies are the one part of a plumbing system the code requires to be examined

again after the installation is accepted, and the rule is printed as two parts. Annual inspections are

made of all backflow prevention assemblies and air gaps to determine whether the assemblies are operable

and the air gaps exist (IPC 2024, 312.11.1). The listed assemblies — reduced pressure principle, double

check, pressure vacuum breaker, reduced pressure detector fire protection, double check detector fire

protection and spill-resistant vacuum breaker backflow preventer assemblies, and hose connection

backflow preventers — are tested at the time of installation, immediately after repairs or relocation

and at least annually; the testing procedure follows one of the standards printed in the section, and

the test gauges conform to the gauge standard named there (IPC 2024, 312.11.2). Which assembly belongs

on a given connection is a separate printed table, and the assemblies are applied as that table directs

(IPC 2024, 608.1). On a nonpotable water reuse system the same inspection and testing is required of the

backflow prevention assemblies serving it (IPC 2024, 1302.12.4).

7. Disinfection, and the certification that follows a repair

A potable water system is not put into use before it is cleaned and disinfected, and the code fixes both

the sequence and the strength of the solution. New potable water systems are 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 the procedure of AWWA C651

or AWWA C652 or the procedure printed in the section. That procedure is a flush with clean potable water

until dirty water does not appear at the points of outlet; a fill with a water/chlorine solution of not

less than 50 parts per million of chlorine standing for 24 hours, or of not less than 200 parts per

million of chlorine standing for 3 hours; a further flush with clean potable water until the chlorine is

purged; and a repeat of the procedure where a bacteriological examination shows contamination remains

(IPC 2024, 610.1). An individual water supply system is disinfected by the same section after

construction, having first been purged of deleterious matter (IPC 2024, 602.3.4).

Georgia states two things about that section that a candidate sitting the Georgia examination needs. The

first is the scope of the requirement: the state's amendment revises it to read « new or repaired potable

water systems », so that a repaired system is disinfected and not only a new one, and it keeps the

prescribed-method order with the health authority or water purveyor first (GA-rule, l. 892). The second

is that a system that cannot be adequately flushed and purged may require disinfection in accordance

with a prescribed method rather than the printed procedure (GA-rule, l. 892).

8. Where the tests stand in Georgia, and what this corpus does not carry

Georgia removes the code's administrative chapter and keeps its testing chapter, and the two sentences

sit in different documents. The amendment instructs that Chapter 1, « Scope and Administration », be

deleted entirely and without substitution, remaining in the Code as a reference guide for local

governments developing their own administrative procedures (GA-rule, l. 44) — so the inspection and

testing provisions of Chapter 1, including the testing of new, altered, extended or repaired systems

(IPC 2024, 111.4.1) and the reinspection and testing of work that failed, are not part of the adopted

Georgia code, and the permit holder's tests under Section 312 are. Section 312 is not amended by the

Georgia rule: the tests of Sections 312.2 through 312.11, the test media, the pressures, the holding

times and the annual inspection and testing of backflow prevention assemblies stand as printed in the

code Georgia adopts.

Two further Georgia lines bear on when a test may be made. All excavations required for the installation

of a building sewer or building drainage system within the walls of a building are open trench work and

are to be kept open until the piping has been inspected, tested and approved (GA-rule, l. 209) — the

trench is not backfilled over work that has not been tested. And backfilling is regulated in layers with

the pipe supported and aligned: loose earth free from rocks, broken concrete and frozen chunks is placed

in the trench in 6-inch (152.4 mm) layers and tamped until the crown of the pipe is covered by a minimum

of 6 inches (152.4 mm) of tamped earth, brought up evenly on both sides so that the pipe remains aligned,

and where the manufacturer's installation instructions for the material are more restrictive than the

code, the more restrictive requirement is followed (GA-rule, l. 203).

Two tests the area's outline names are not carried by the plumbing code and are not asserted here. The

outline lists, under testing, the pressure testing of gas lines with air (GA-bulletin, l. 406, GA-bulletin,

l. 409). Gas piping is not a subject of this code: the code's scope states that the installation of fuel

gas distribution piping and equipment, fuel-gas-fired water heaters and water heater venting systems is

regulated by the International Fuel Gas Code (IPC 2024, 101.2), and the same sentence is the first

sentence of the general applicability section Georgia adds to its own code (GA-rule, l. 151). No gas

test pressure, holding time or gauge is stated in this text, and the certification of a backflow test is

the assembly testing the code prints (IPC 2024, 312.11.2) rather than a state certificate form, which the

pieces filed here do not carry.