Section 170.424  Venting of Tanks

This Section is applicable to motor fuel tanks located at service stations, unless otherwise noted.

a)         Each tank shall be provided with a separate normal working vent pipe, connected with the top of the tank and carried up to the outer air.  Underground manifolding of normal working vents is prohibited.  The pipe shall be arranged for proper drainage to the storage tank, and its lower end shall not extend through top of 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.   Manifolded normal vents installed on USTs located at facilities which were existing prior to April 1, 1995 may be left in place provided that the vents can be shown, by field verification, to comply with NFPA 30 vent requirements, incorporated by reference in Section 170.410.

b)         The upper end of the pipe shall be provided with an updraft vent device only, with 40 gauge screening, unless alterations are required by Stage II Vapor Recovery.

c)         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 170.410, and in no case less than one and one-fourth inches 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.

d)         The vent pipe shall terminate outside buildings at a point one foot above the level of the highest remote fill or any fill from which the tank may be filled, 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 any air intake of any building, and in a location which will not permit pocketing of vapor or liquid. The vent piping shall project above the canopy facia no less than 4 feet.

e)         Underground manifolding of normal working vents is prohibited.  Manifolding of special purpose vents, such as for vapor recovery, is allowed in accordance with NFPA 30 2-3.6.3, incorporated by reference in Section 170.410. Manifolding on normal working vents aboveground is allowed providing the following steps are followed:

1)         Manifolding will be installed no less than 3 feet above grade and no more than 5 feet aboveground.

2)         Each vent shall be capable of being separated and isolated from the manifold.

3)         Class II & III products cannot be attached to a manifold that includes Class I products.

4)         Final riser shall be of adequate sizing as specified by NFPA 30, as incorporated in Section 170.410.

f)          No vent piping is allowed inside buildings.  Existing vent piping inside buildings may remain if approved by OSFM Division of Fire Prevention.  It is recommended that Stage II Vapor Recovery vent piping be connected to an individual tank opening.

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

h)         Hazardous substance tanks shall be vented in accordance with NFPA 30, incorporated by reference in Section 170.410 or as approved by the Office of the State Fire Marshal to be no less protective of human health or the environment.

(Source:  Amended at 27 Ill. Reg. 8164, effective May 1, 2003)