McTighe Industries builds cylindrical double wall oil-water separators for applications where secondary containment is required. All secondary containment units allow for free flow of fluid in the interstitial space and have a 2" interstitial monitoring port(s) for leak detection capabilities. The interstitial space can be easily monitored. Recommended methods of monitoring may vary with different agencies, regulatory authorities, or codes. See Section 6 of this catalog for information on a leak detection system.

Underwriters Laboratories UL-58 (Steel Underground Tanks for Flammable and C7ombustible Liquids) classify double wall construction types into two categories -- UL Type I and UL Type II. Recent changes in UL-58 make the Type I and Type II double wall designs very similar. The main difference between these two designs is the thickness requirement of the outer steel shell.

Another Underwriters Laboratories Standard for Safety provides construction criteria for a jacketed secondary containment system. UL-1746 (External Corrosion Protection Systems for Steel Underground Storage Tanks) Part III jacketed construction provides 360 degree double wall protection, consists of a steel inner shell built to UL-58, and a fiberglass outer shell in accordance with UL-1746. The classification of the double wall designs is sometimes confusing because the jacketed design is also classified as a Type II double wall meaning it provides complete containment of the inner vessel.

Further description of these double wall classifications and separator construction details are included in this section.

McTighe can also supply secondary containment configurations for the rectangular oil-water separators. Contact McTighe for more information on this application.