5704.2.9.6.8 Tank openings.

Tank openings in protected aboveground tanks shall be through the top only.

5704.2.9.6.9 Antisiphon devices.

Approved antisiphon devices shall be installed in each external pipe connected to the protected aboveground tank when the pipe extends below the level of the top of the tank.

5704.2.10 Drainage and diking.

The area surrounding a tank or group of tanks shall be provided with drainage control or shall be diked to prevent accidental discharge of liquid from endangering adjacent tanks, adjoining property or reaching waterways. The area shall be in compliance with the requirements of the New York State Department of Environmental Conservation regulations, as set forth in 6 NYCRR Part 613.

   Exceptions:

      1.   For tanks having a capacity of less than 10,000 gallons (37 850 L), the commissioner may modify these requirements based on an approved technical report which demonstrates that such tank or group of tanks does not constitute a hazard to other tanks, waterways or adjoining property, after consideration of special features such as topographical conditions, nature of occupancy and proximity to buildings or structures on the same or adjacent property, capacity, and construction of proposed tanks and character of liquids to be stored, and nature and quantity of private and public fire protection provided.

      2.   Drainage control and diking is not required for listed secondary containment tanks.

5704.2.10.1 Volumetric capacity.

The volumetric capacity of the diked area shall not be less than the greatest amount of liquid that can be released from the largest tank within the diked area. The capacity of the diked area enclosing more than one tank shall be calculated by deducting the volume of the tanks other than the largest tank below the height of the dike.

5704.2.10.2 Diked areas containing multiple tanks.

Diked areas containing multiple tanks shall be subdivided in accordance with NFPA 30.

5704.2.10.3 Protection of piping from exposure fires.

Piping shall not pass through adjacent diked areas or impounding basins, unless provided with a sealed sleeve or otherwise protected from exposure to fire.

5704.2.10.4 Combustible materials in diked areas.

Diked areas shall be kept free from combustible materials, drums and barrels.