Section 175.440  Venting of Tanks

a)         Vents

1)         Each tank shall be provided with a separate working vent pipe, connected with the top of the tank and carried up to the outer air. Except as allowed in subsection (b), manifolding of working vents is prohibited. The pipe shall be arranged for proper drainage to the storage tank, and its lower end shall not extend through the top of the tank for a distance of more than one inch; it shall have no traps or pockets. Float vent valve overfill devices are not considered an extension of the standard vent.

2)         The upper end of the pipe shall be provided with an updraft vent device only, with 40 gauge screening. A pressure vacuum vent will meet this requirement.

3)         The vent pipe shall be of sufficient cross-sectional area to permit escape of air and vapor during the filling operation and in compliance with NFPA 30, incorporated by reference in 41 Ill. Adm. Code 174.210, and in no case less than 1¼" in diameter. If a power pump is used in filling the storage tank, and a tight connection is made to the fill pipe, the vent pipe shall not be smaller than the fill pipe.

4)         Exposed vents above grade must be of steel construction or other material as approved by OSFM during the permit process.

5)         Vents attached to buildings shall be securely fastened to avoid damage from wind and testing procedures. When free-standing vents are installed, the vent pipes shall be capable of supporting themselves with respect to normal loads imposed by wind and testing procedures.

6)         The vent pipe shall terminate outside buildings:

A)        at a point not less than 12 feet above the adjacent ground level and not less than 5 feet, measured vertically and horizontally, from any window or other building opening, such as a basement, cellar, pit, ventilated soffit or air intake of any building;

B)        in a location that will not permit vapors to accumulate or travel to an unsafe location, enter building openings, or be trapped under eaves, and that is at least 15 feet (4.5 meters) from powered ventilation air intake devices; and

C)        in a manner so that the vent piping shall project above any canopy facia no less than 4 feet.

7)         No vent piping is allowed inside buildings. Existing vent piping inside buildings may remain if approved, in writing, by OSFM.

8)         Adequate collision protection to protect against physical damage shall be provided for vent piping.

9)         Hazardous substance tanks shall be vented in accordance with a nationally recognized standard for the substance contained within the tank or as approved by OSFM to be no less protective of human health or the environment.

b)         Exceptions to Ban on Manifolding Vents

Manifolded vents existing as of May 2, 2023 may be left in place, provided that the vents can be shown, by field verification, to comply with OSFM rules at the time of installation.  On or after May 2, 2023, new manifolding shall not be allowed except as approved by OSFM based on a Licensed Professional Engineer's certified engineering plans submitted at the time of permit application.

(Source:  Amended at 47 Ill. Reg. 6837, effective May 2, 2023)