In an industry dominated by concrete and steel since its inception, plastic is proving to be an increasingly worthy adversary. Well, that’s the nice way to say it. But as engineers, we far prefer the blunt version. Injection molded thermoplastics are now the premier grease interceptor construction material. Here’s why.
Concrete WILL crack
When grease begins to breakdown, it’s sulfate molecules become sulfides, and eventually sulfuric acid. When the acid makes contact with the calcium hydroxide in concrete, a layer of gypsum is formed on the walls of the interceptor. Normally this process wouldn’t affect structural integrity, but the gypsum is easily rinsed away during routine cleaning, exposing more and more aggregate over time.
This alone will eventually lead to cracks, but when combined with concrete’s porous qualities, it’s a recipe for disaster. A restaurant owner would be lucky to get eight years out of a concrete interceptor before its inevitable catastrophic failure, resulting in astronomical excavation and replacement fees.
Steel WILL rust, then crack
If scientists were challenged to find an optimal rusting agent, salt laden grease would certainly make the short-list. You’ve seen what salt can do to cars, and if that wasn’t bad enough, the reaction that creates sulfuric acid in concrete traps also occurs in steel traps. And once the pitting starts eating away at weld points, a steel interceptor might last three years.
Seek solace in plastic
Injection molded thermoplastic interceptors are seamless, one piece, grease devouring machines. Guaranteed to last at least 10 years, plastic interceptors have smooth walls that are extremely difficult for grease and bacteria to cling to. And while steel and concrete advocates like to claim that plastic interceptors tend to float in areas with high water tables, developments like ground anchors and closed corrugations keep them sunk as stone (with none of the cracks).