Illinois Administrative Code
Title 77 - PUBLIC HEALTH
Part 890 - ILLINOIS PLUMBING CODE
Subpart M - INSPECTIONS, TESTS, MAINTENANCE AND ADMINISTRATION
Appendix A - Plumbing Materials, Equipment, Use Restrictions and Applicable Standards
Table C - Minimum Air Gaps for Plumbing Fixtures
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Minimum Air Gap (Inches) |
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When Not Affected by Near Wall1 |
When Affected by Near Wall2 |
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Lavoratories and other fixtures with effective opening not greater than 1/2 inch diameter. |
1 |
11/2 |
|
Drinking water fountains, single orifice 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 |
11/2 |
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Sink, laundry trays, goose neck bath faucets and other fixtures with effective opening not greater than one inch diameter. |
11/2 |
21/4 |
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Stills, sterilizers and other appliances, fixtures, devices and water and waste connections used for preparation of sterile material. |
2 |
3 |
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Over rim bath fillers and other fixtures with effective openings not greater than one inch diameter. |
2 |
3 |
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Effective openings greater than one inch. |
2 X Diameter of effective opening |
3 X Diameter of effective opening |
1 Side walls, ribs or other similar obstructions do not affect air gaps when spaced from inside edge of spout opening a distance greater than three times the diameter of the effective opening for a single wall, or a distance greater than four times the diameter of the effective opening for two intersecting walls.
2 Vertical walls, ribs or similar obstructions extending from the water surface or to above the horizontal plane of the spout opening require a greater air gap when spaced closer to the nearest inside edge of spout opening than specified in Footnote 1 above. The effect of three or more such vertical walls or ribs has not been determined. In such cases, the air gap shall be measured from the top of the wall.
