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What Size Grease Trap Do I Need For Commercial Kitchen?

Last Updated on April 28, 2024 by Lauren Beck

In a busy commercial kitchen where equipment like ovens, stoves, and refrigerators are always operating, it is vital not to ignore the importance of the grease trap.

From my experience working in a restaurant, I learned that having the right size and quality of grease trap can lead to disaster. 

So, if you’re still wondering, “What size grease trap do I need for commercial kitchen?” don’t worry.

I’ll provide the information on choosing the right-sized grease trap without getting too complicated and what size is necessary for your commercial kitchen. 

What Size Grease Trap Is Necessary For A Commercial Kitchen?

To ensure efficient grease management in your commercial kitchen, choosing the right grease trap size for your dish machine is essential. 

Below are the recommended grease trap sizes by the Plumbing and Drainage Institute:

Dish Machine Tank CapacityRecommended Grease Trap Size
10-15 Gallons15 Pound Grease Trap
20-30 Gallons20 Pound Grease Trap
30-50 Gallons25 Pound Grease Trap
50-70 Gallons35 Pound Grease Trap
70-100 Gallons100 Pound Grease Trap

“Choosing the appropriate grease trap size ensures effective grease removal and keeps your kitchen running smoothly, preventing costly plumbing issues.” – shares George Hull, owner of Septic Tank Cleaning Langley BC, a reputable septic service in the Greater Vancouver area, emphasizes the importance of proper grease trap sizing especially for businesses. 

Factors To Consider On What Grease Trap Size You Need 

A. Local Plumbing Codes

These adhere to Plumbing and Drainage Institute (PDI) guidelines but can vary by location. They dictate the design and installation standards for your grease traps, ensuring kitchen safety. 

Consult with local authorities to ensure your grease traps meet all local regulations.

B. Rate Of Incoming Flow

This is the amount of water flowing from faucets in gallons per minute (GPM). 

It directly influences the required grease trap capacity. Generally, your grease trap should be twice the size of the flow rate. 

How Should A Commercial Grease Trap Be Measured?

1. Measure Sink Capacity

Begin by measuring each sink’s capacity in cubic inches. To do this, multiply the sink’s length, width, and depth. 

If you have multiple sinks or compartments, add their capacities to find the total cubic inches.

2. Convert To GPM

To determine the necessary grease trap capacity in gallons per minute (GPM), divide the total cubic inches by 231. 

This conversion ensures you have the appropriate GPM capacity to handle the flow.

3. Adjust For Any Displacement

Consider any obstructions or fixtures in your sink that may limit the grease flow into the trap. This adjustment considers the actual usable capacity of your sink.

4. Include Additional Appliances

If you have other appliances in your kitchen that discharge into the grease trap, make sure to factor them in when calculating the needed capacity.

5. Calculate The Drainage Period & Flow Rate

Typically, assume a 1-minute drainage period unless specific conditions allow 2 minutes. 

The drainage period represents the time the fixture takes to drain completely.

6. Select the Appropriate Interceptor

Choose the interceptor size that matches or exceeds your calculated needs. Rounding up to the next larger interceptor size ensures efficient grease management.

How Far Should You Place A Grease Trap From A Sink?

To ensure your grease trap works well in a commercial kitchen, keep it at least 10 feet away from sinks and dishwashers. 

This distance gives the wastewater enough time to cool down. Hot water and grease don’t mix nicely in pipes – hot grease can turn solid and clog them. 

By following this rule and giving space between the grease trap and your kitchen sinks, you avoid plumbing problems and keep your kitchen running smoothly. It’s a simple step that makes a big difference.

Can A Grease Trap Be Too Large?

Cleaning Grease Trap

It’s not always good if a grease trap is too large. According to the Plumbing and Drainage Institute (PDI), excessive sizing can lead to problems. 

Oversized grease traps may need to be fixed. 

They can cause the plumbing, interceptor, and drainage system to deteriorate due to low flow rates, allowing grease to accumulate and solidify within the trap. 

As such, it can lead to costly maintenance and repair issues. 

How Much Does It Typically Cost To Install A Grease Trap?

The cost of installing a grease trap in a commercial kitchen can vary significantly. On average, you should budget between $1,000 to $5,000. 

The main contributors to the overall cost are the grease trap device’s size, complexity, and installation labor.

Smaller and simpler units tend to be on the lower end of this range, while larger or more intricate systems can reach the higher end.

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How do grease traps and grease interceptors differ?

Grease traps are designed for low-pressure water environments, while grease interceptors are better suited for high-pressure settings. 

Understanding these distinctions is vital for selecting the right grease management solution for your kitchen needs.

How big are grease traps in restaurants?

Grease traps in restaurants typically range in size, with common options being 70 to 90-pound capacity units. 

The specific size required depends on the restaurant’s kitchen setup and the volume of grease produced during food preparation.

What are the downsides of grease traps?

Grease traps, if not properly maintained, can lead to drainage problems. Excessive grease accumulation can block water flow, causing kitchen sinks and appliance issues. 

It also includes corrosion issues, cleaning challenges, potential damage to trap components, and reduced efficiency in capturing grease, which can result in plumbing problems and costly maintenance.

Key Takeaways

Choosing the right size grease trap for your commercial kitchen is a pivotal decision that can’t be taken lightly. 

Drawing from my own experiences and insights, it’s evident that two major factors must be considered. 

Firstly, the rate of incoming flow, typically measured in gallons per minute (GPM), directly affects the grease trap’s capacity, with the accepted norm being double the flow rate. 

Secondly, following Plumbing and Drainage Institute (PDI) guidelines, local plumbing codes ensure safe and compliant installation. 

To create an efficient and legally sound grease management system, it’s essential to balance these factors. 

Lauren Beck

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