HPAC Magazine

Grease lightning: Have pride in that ride

March 1, 2016 | By Andrew Bird

Are you up to speed on grease management?

The grease management industry has developed significantly in the past decade with not only more advanced and improved products, but also development of performance standards, such as CSA B481-2012, and the harmonization of common terms and references, both in Canada and the US.

Like most industries these days, grease management while conceptually simple, is full of terms, references and acronyms. Would you know an HGI from a GRD or a GGI? What is the difference between gpm and gallons? How is the right size and format of product selected for a particular application?


Grease Interceptor: A plumbing appurtenance or appliance that is installed in a sanitary drainage system to intercept non-petroleum fats, oil, and grease (FOG) from a wastewater discharge.


At its core and still prevalent, the term “grease trap” is commonly heard, even though this is progressively disappearing from technical and reference language.

This change is slow, particularly within the contracting and supply chain. But based on an industry-wide recognition that the term “trap” suggests the presence of a water seal as part of the interceptor, like a p-trap under a sink, the purpose is to retain an amount of liquid to stop gases and unpleasant odours from entering the occupied areas of a building through the drains.

Based on bad operational experiences and challenges, the function of grease interceptors was recognized to be more seriously impacted by air pressure changes and balancing in the drainage system.

If installation or system issues created a negative pressure in the interceptor the risk was significant that fats, oils and grease (FOG) once captured could later be literally sucked into the downstream system.

Given that the “trap” was intended to prevent fats, oil and grease from entering the municipal drainage and sewer system, this was clearly an issue.

Today, modern interceptors are generically designed and required by North American plumbing codes to be externally vented and trapped, in conjunction with external water seal traps as a standard part of the system.

What does this mean for a food service operator? Use a professional, licensed plumber for installation and understand the product that is being installed, signing off only when you are satisfied and most importantly understanding and implementing the maintenance requirements for that product.

Generically, the term “grease interceptor” regardless of type is defined as a plumbing appurtenance or appliance that is installed in a sanitary drainage system to intercept non-petroleum FOG from a wastewater discharge.

Grease interceptors can be categorized into three generic types: hydromechanical (HGI), gravity (GGI) and grease removal device.

Hydromechanical Grease Interceptor (HGI)
• Managed flow rate
• Design elements/features to force FOG separation
• National Performance Standards (CSA B481)
• Compact, high efficiency performance
• Commonly found inside the building, on or recessed into the floor

Gravity Grease Interceptor (GGI)
• Uncontrolled flow of influent
• Rely on gravity and time (min 30 mins) to separate FOG from water
• No applicable performance standards
• Traditionally concrete or fiberglass construction
• Typically outside the building due to size and nature of maintenance

Grease Removal Device (GRD)
• Based on functional principles of HGI
• Located inside the building
• Need electrical and for some, other service connections e.g. hot water
• FOG skimmed periodically to a separate container
• Best suited to serving a single, high FOG producing appliancedevices (GRDs).

Now that you know your interceptors, how do you determine which is the best choice for the installation or application?

The good news is that a CSA committee, which was responsible for developing and writing the CSA B481-Series of Standards for Grease Interceptors, has done most of that work.

By comparison, the HGI as a generic type of interceptor, is very much an engineered solution specifically designed for the purpose of effectively and efficiently separating FOG from wastewater.

Like most products this is a good, better, best situation with products that have not changed for many years to others that continue to actively grow, develop and improve upon the solutions offered to customers.

The National Plumbing Code of Canada (NPC) as of 2012 began to reference the then recently published and updated CSA B481-2012 Standard, the scope of which is for grease interceptors up to a 100 gpm flow rate.

Not only does this standard reference the separation performance of the interceptor offering two methods of performance evaluation (481.1 – test methods and rating using lard; and 481.2 – test method and rating using oil), it additionally qualifies minimum requirements for materials of construction, cover load ratings, crush resistance, leak testing and so on (481.0). Parts 3, 4 and 5 in turn address sizing, location and installation; maintenance; and, performance of interceptors fitted with removal devices (GRDs), respectively.

Having been published into NPC, one by one the provincial plumbing codes have in turn also adopted the same reference, giving an almost consistent basis and model of application across Canada.

Of course there are always a couple of exceptions, for example Metro Vancouver adopted its own sizing methodology due to historic and perceived local constraints.

Ontario has a different view and requirements regarding the location of flow control devices.

Exceptions aside, CSA B481 has provided this sector of industry with a consistent model document on which to base local ordinance. In turn, cities are now adopting and referencing that Standard at their own levels.

The City of Toronto has conducted an extended period of review and public consultation beginning in 2014. Having concluded that process and submitted recommendations to City Council in late 2015 and again with amendments in February 2016, they have now approved updates regarding grease interceptor requirements for all commercial foodservice establishments as part of a wider review of the City of Toronto Sewers By-Law.

These updates reference CSA B481 and are being implemented immediately. This will result in a proactive compliance review period, requiring new and existing installations be brought in line with the new by-law requirements.

Toronto is being watched closely by a number of other major Canadian cities and is expected to be a benchmark for them in making similar implementations.

Part of the compliance program for the City of Toronto will be reviewing the size of grease interceptor in use to ensure that it is adequately sized for its application and that it meets the CSA performance requirements.

Sizing of an interceptor is often seen as a challenge but is key to the successful operation in its intended application.

A foodservice operator has to consider their grease interceptor like their car. You cannot viably fit a family of six in a five-seat saloon car that has not been serviced or maintained for the last 50,000 kilometers and realistically expect to make it to your destination.

Similarly, trying to save a few dollars on the cost of your grease interceptor is a completely false economy.

Without the proper maintenance and product characteristics best suited to the application, chances are that the interceptor will be a constant source of irritation and downright loathing.

Call-backs, blockages, foul odours, leaks and progressive loss of performance due to corrosion are all common complaints.

Correct sizing of the interceptor is key and any product manufacturer worth your patronage as a product installer will assist in sizing and review your application to identify the right product for the job at hand.

Many manufacturers have simple online calculation tools or apps that can guide you in making the correct determination of the size required. Once installed, take a couple of pictures and send them to the manufacturer to verify that the installation has been made correctly.

When handing over to the owner or manager of a foodservice location, be sure to hand on any instruction or product information for their reference.

When all is said and done, a foodservice operator should consider a grease interceptor to be their best friend, not their worst enemy.

Yes, there is some cost involved. Yes, regular maintenance is a necessary evil, but back to the car analogy. You can drive a vehicle that you do not service, that is consequently in poor mechanical and operational repair, and leaks on your garage floor, belches foul-smelling blue smoke and that you know is going to get you pulled over or let you down at the most inconvenient time possible–either way you are paying an unexpected bill. Or, you can replace that vehicle with something newer, maybe even new off of the lot. Financially it hurts for a week or so, but you now have some peace of mind and pride in your ride.

Sized, specified, installed and maintained correctly, find a product that you as an installer can be confident in and, like the car, encourage pride in every GI installed.

Love them or hate them with a passion, there is a GI for every application. HGIs, GGIs or GRDs all have their place. That interceptor is a foodservice operator’s best opportunity to avoid potentially significant fines and penalties, not to mention the cost of clean-up, environmental impact and other consequences were an overflow to occur. <>

Andrew Bird is business development manager for the Endura Separation Technologies Group at Canplas Industries Ltd., in Barrie, ON. Canplas Industries Ltd. is an Aliaxis Group company, a manufacturer of plastic solutions for fluid transport in the field of construction materials. www.canplas.com
1 Influent – Wastewater containing non-petroleum fats, oils and/or grease



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