Heat Tracing System for F.O.G. Waste

Plumbing Coordinator Sean Thompson, gives information on an issue he tries to prevent when designing plumbing systems. Check out his opinion on what will work best to prevent most commercial kitchen pipe backups.

Fats, oils and grease, also called FOG, are produced from foods like meat fat, gravy, butter, ice cream, cooking oils/fryers etc.  Other sources of FOG are mops for floor cleaning, pot sinks & dishwashers, and commercial kitchens. FOG will be in either a liquid or solid form and will turn either to viscous or solid as it is cooled in the underground drainage system. It will slow drainage, cause restrictions, and eventually clog the pipe. It’s common for these types of clogs to form a total blockage of a section of pipe.

There are several maintenance management programs to help control and reduce the amount of FOG being introduced into the drainage system, but none are foolproof. FOGs will inevitably make their way into the drainage system. Municipalities certainly do not like FOGs to reach their systems or treatment facilities and will hand out violations with hefty fines or, in some cases, they will halt operation of businesses.

This is the reason we design for the installation of grease traps / interceptors, particularly for commercial kitchens and dining facilities/restaurants. The grease interceptors’ main functions are to separate grease from the wastewater to keep it from entering the municipalities sanitary system and store grease for removal.  

The key to preventing clogs and drainage issues in the grease waste system is keeping FOG in suspension from the kitchen to the interceptor. The longer the run is from the kitchen, the more difficult this becomes and can contribute to FOG solidifying in the pipe and impeding the function of the interceptor allowing small, solidified particles to pass into the municipalities sanitary sewer system.

A Heat Trace System, a set of paths lined along pipes or vessels, is a great option to keeping these waste mixtures in suspension by keeping temperatures above where grease starts to become viscous and solidify. They are designed to maintain temperatures in the pipe that will convey FOG to an interceptor and allow FOG mixtures to remain in a liquid state to maintain flow.

Designing for a grease waste heat trace system will reduce expensive maintenance costs, fines rendered from municipalities & loss of business due to odors & unsanitary conditions caused by a poorly functioning grease waste and containment system.

When to push for a Heat Trace System?

It is strongly recommended to heat trace the entire grease waste main in systems when the grease interceptor will be 35’ or more from the kitchen, so it’s best to try to design the interceptor as close to the kitchen as possible.

In systems where the grease waste main piping is 100’ or more total, from the start of the main to the interceptor, the main and long branch runs should be heat traced.

Commercial kitchens for a dining establishment, or similar type establishments serving ice cream/yogurt etc, are recommended to heat trace the entire main and long branches regardless of pipe lengths. Ice cream and milk fats tend to solidify more quickly than FOG.

In my opinion, it is always a good idea to heat trace a grease waste system, but realistically, there are not codes to reference for its use, and we all know the budget will dictate some VE items and this system will be on the chopping block very quickly. Especially because it is not “required by code”.