RELATES TO: KRS 318.130, 318.150, 318.165,
NECESSITY, FUNCTION, AND CONFORMITY: KRS 318.130 requires the department to promulgate administrative regulations establishing the Kentucky State Plumbing Code regulating plumbing, including the methods and materials that may be used in Kentucky. This administrative regulation establishes the types of piping and pipe sizes required for a potable water supply system and the methods to be used to protect and control the water supply system and requires the manufacturer's specification number of the material accepted in those installations to be identified and published.
MINIMUM AIR GAPS FOR PLUMBING FIXTURES | ||
Fixture | Minimum Air Gap | |
When not affected by near wall (inches) | When affected by near wall (inches) | |
Lavatories and other fixtures with effective opening not greater than 1/2 inch diameter | 1 | 1 1/2 |
Sink, laundry trays, gooseneck bath faucets and other fixtures with effective openings not greater than 3/4 inch diameter | 1 1/2 | 2 1/4 |
Over rim bath fillers and other fixtures with effective openings not greater than 1 inch diameter | 2 | 3 |
Drinking water fountains - single office not greater than 7/16 (0.437) inch diameter or multiple orifices having total area of 0.150 square inches (area of circle 7/16 inch diameter) | 1 | 1 1/2 |
Effective openings greater than 1 inch | 2 x diameter of effective opening | 3 x diameter of effective opening |
NOTE 1. Side walls, ribs, or similar obstructions do not affect air gaps if spaced from the inside edge of the spout opening a distance greater than three (3) times the diameter of the effective opening for a single wall, or a distance greater than four (4) times the diameter of the effective opening for two (2) intersecting walls.
NOTE 2. Vertical walls, ribs, or similar obstructions extending from the water surface to or above the horizontal plane of the spout opening require a greater air gap if spaced closer to the nearest inside edge of spout opening than specified in NOTE 1 above. The effect of three (3) or more vertical walls or ribs has not been determined. In this case, the air gap shall be measured from the top of the wall.
CRITICAL LEVEL (CL) SETTINGS FOR ATMOSPHERIC TYPE VACUUM BREAKERS | |
Fixture or Equipment | Method of Installation |
Aspirators, ejectors, and showers | CL at least 6 in. above flood level of receptacle |
Bidets | CL at least 6 in. above flood level of receptacle |
Cup beverage vending machines | CL at least 12 in. above flood level of machine |
On models without built-in vacuum breakers: | |
Dental units | CL at least 6 in. above flood level rim of bowl |
Dishwashing machines | CL at least 6 in. above flood level of machine |
Flushometers (closet & urinal) | CL at least 6 in. above top of fixture supplied |
Garbage can cleaning machines | CL at least 6 in. above flood level of machine |
Hose bibs (sinks or receptacles) | CL at least 6 in. above flood level of receptacle served |
Hose outlets | CL at least 6 in. above highest point on hose line |
Laundry machines | CL at least 6 in. above flood level of machine |
Lawn Sprinklers | CL at least 12 in. above highest sprinkler or discharge outlet |
Steam tables | CL at least 12 in. above flood level |
Tanks & vats | CL at least 6 in. above flood level rim or line |
APPLICATION TABLE | |||||
TYPE AND PRESSURE | DESCRIPTION | INSTALLED AT | EXAMPLES OF INSTALLATIONS | APPLICABLE SPECIFICATIONS | |
Reduced pressure principle backflow preventer for high hazard cross connections | Two independent check valves with intermediate relief valve. Supplied with shutoff valves and ball-type test cocks. | All cross connections subject to backpressure or back siphon-age if there is a high potential health hazard from contamination. Continuous pressure. | Main supply lines, commercial boilers, cooling towers, hospital equipment, processing tanks, laboratory equipment, waste digesters, car wash, sewage treatment, lawn sprinklers | ASSE No. 1013 AWWA C506 FCCCHR of U.S.C. CSA B.64.4 Sizes 3/4" - 10" | |
(A) Double check valve assembly for low hazard cross connections | Two independent check valves. Supplied with shutoff valves and ball type test cocks. | All cross connections subject to back pressure if there is a low potential health hazard or nuisance. Continuous pressure. | Main supply lines, food cookers, tanks and vats, commercial pools | NONTOX-IC | ASSE No. 1015 AWWA C506 FCCCHR of U.S.C. CSA B.64.5 Sizes 3/4" - 10" |
(B) Dual check valve backflow preventer for low hazard applications | Two independent check valves. Checks are re-movable for testing | Cross connections if there is a low potential health hazard and moderate flow requirements. | Post ground hydrants | ASSE No. 1024 Sizes 3/4" & 1" | |
(A) Backflow preventer with intermediate atmospheric vent for moderate hazard cross connections in small pipe sizes | Two independent check valves with intermediate vacuum breaker and relief valve. | Cross connections subject to back pressure or back siphonage if there is a moderate health hazard. Continuous pressure. | Boilers (small), cooling towers (small), dairy equipment residential | ASSE No. 1012 CSA B.64.3 Sizes 1/2" & 3/4" | |
(B) Backflow preventer for carbonated beverage machine | Two independent check valves with a vent to atmosphere | On potable water distribution lines serving beverage dispensing equipment to prevent back-flow of carbon dioxide gas and carbonated water into the water supply system. | Postmix carbonated beverage machine | ASSE 1022 | |
(C) Laboratory faucet and double check valve with intermediate vacuum breaker in small pipe sizes for moderate to low hazard | Two independent check valves with intermediate vacuum breaker and relief vent. | Cross connection subject to back pressure or back siphonage if there is a moderate to low health hazard. | Laboratory faucets and pipe lines, barber shop and beauty parlor sinks | ASSE No. 1035 (N-LF9) | |
(A) Atmospheric vacuum breakers for moderate to high hazard cross connections | Single float and disc with large atmospheric port. | Cross connections not subject to backpressure or continuous pressure. Install at least 6" above fixture rim. Protection against back siphonage only. | Process tanks, dishwashers, soap dispensers, washing machines | ASSE No 1001 ANSI.A112.1.1 CSA B.64.1.1 FCCCHR of U.S.C. Sizes 1/4" - 3" | |
(B) Antisiphon pressure breakers for moderate to high hazard cross connections | Spring loaded single float and disc with independent 1st check. Supplied with shutoff valves and ball type test cocks. | This valve is designed for installation in a continuous pressure potable water supply system 12" above the overflow level of the system being supplied. Protection against back siphon-age only. | Laboratory equipment, cooling towers, commercial laundry machines, swimming pools, commercial plating tanks, large toilet total & urinal facilities, degreasers, photo tanks, livestock water systems, lawn sprinklers | ASSE No. 1020 CSA B.64.1.2 FCCCHR of U.S.C. Sizes 1/2" - 2" | |
(C) Hose connection vacuum breakers for residential and industrial hose supply outlets | Single check with atmospheric vacuum breaker vent. | Install directly on hose bibs, service sinks and wall hydrants. Not for continuous pressure. | Hose bibs, service sinks, hydrants | ASSE No. 1011 CSA B.64.2 Size 3/4" Hose |
CROSS CONNECTIONS, DEGREE OF HAZARD AND ACCEPTABLE PROTECTION FOR VARIOUS PLUMBING OUTLETS AND CONNECTIONS | ||||||||
Degree of Hazard | Acceptable Protection | |||||||
Type of Connection | Backflow | Backsiphonage | ||||||
Severe | Moderate | Minor | Air Gap | Reduced Pressure Device | Double Check Valve Assembly | Pressure Type Vacuum Breaker | Atmospheric Type Vacuum Breaker | |
I. Connections subject to back pressure from: | ||||||||
A. Pumps, tanks, and lines handling: | ||||||||
1. Toxic substance | X | X | X | |||||
2. Nontoxic substance | X | X | X | X | ||||
B. Boilers | ||||||||
1. With chemical additives | X | X | X | |||||
2. Without chemical additives | X | X | X | X | ||||
C. Gravity due to obvious site conditions subject to: | ||||||||
1. Contamination by toxic substances | X | X | X | |||||
2. Contamination by nontoxic substances | X | X | X | X | ||||
II. Water outlets and connections not subject to back pressure: | ||||||||
A. Connection to sewer or sewage pump | X | X | ||||||
B. Outlet to receptacles containing toxic substances | X | X | X | X | X | |||
C. Outlet to receptacles containing nontoxic substances | X | X | X | X | X | X | ||
D. Outlet into domestic water tanks | X | EACH CASE TREATED SEPARATELY | ||||||
E. Flush valve toilets | X | X | X | X | X | |||
F. Flush valve urinals | X | X | X | X | X | |||
G. Outlets with hose attachments subject to contamination from: | ||||||||
1. Toxic substance | X | X | X | X | X | |||
2. Nontoxic substance | X | X | X | X | X | |||
H. Outlets to recirculating cooling tower: | ||||||||
1. With chemical additives | X | X | X | |||||
2. Without chemical additives | X | X | X | X |
Fixture Branches | Nominal Pipe Size (Inches) |
Bath tubs | 1//2 |
Combination sink and tray | 1/2 |
Cupsidor | 1/2 |
Drinking fountain | 1/2 |
Dishwasher (domestic) | 1/2 |
Kitchen sink (res.) | 1/2 |
Kitchen sink (com.) | 1/2 or 3/4 as required |
Lavatory | 1/2 |
Laundry tray | 1/2 |
Sinks (service, slop) | 1/2 |
Sinks flushing rim | 3/4 |
Urinal (flush tank) | 1/2 |
Urinal (direct flush type) | 1/2 or 3/4 as required |
Water closet (tank type) | 1/2 |
Water closet (flush valve type) | 1 |
Hot water boilers | 3/4 |
Hose bibs | 1/2 |
Wall hydrant | 1/2 |
Domestic clothes washer | 1/2 |
Shower (single head) | 3/4 |
Sizes of Overflow Pipes for Water Supply Tanks | |||
Maximum capacity of water supply line to tank | Diameter of Overflow pipe (inches ID) | Maximum capacity of water supply line to tank | Diameter of overflow pipe (inches ID) |
0-50 gpm | 2 | 400-700 gpm | 5 |
50-150 gpm | 2 1/2 | 700-1000 gpm | 6 |
150-200 | 3 | Over 1000 gpm | 8 |
815 KAR 20:120
STATUTORY AUTHORITY: KRS 198B.040(10), 318.130