Secondary Containment

What is Secondary Containment?
Secondary containment requirements are found in the International Fire Code, a model code that is extensively used throughout the U.S. for safe building design and function. Most jurisdictions in the U.S. adopt this code as law, with some jurisdictions adopting a variation of it.

For the purpose of distilleries, high proof alcohol/ flammable liquid, secondary containment is a method of containing a potential spill, and containing any possible fire associated with that spill. It is used in certain situations to mitigate a risk of the spread of a dangerous material throughout a building and outside of a building.

Do I need secondary containment in my distillery?
Secondary containment comes into consideration only when you have an H (High Hazard) Occupancy in your building. You become an H-Occupancy when you exceed the Maximum Allowable Quantities of flammable liquid, which for alcohol/ethanol are 240 gallons in a fully sprinklered building and 120 gallons in a non-fully-sprinklered building. Below are a few possiblescenarios that demonstrate when you may or may not need secondary containment:

Scenarios Where Secondary Containment is required:
(Please note this applies for indoor, closed systems)

-Fully Sprinklered Building
-Over 240 gallons of alcohol over 16% ABV (Will be an H-3 Occupancy)
-Alcohol in vessels over 55 gallons, or if total capacity exceeds 1000 gallons (not barrels)

-Non-fully-sprinklered building
-Over 120 gallons of alcohol over 16% ABV (Will be an H-3 Occupancy, the H-3 Occupancy must be sprinkled*)
-Alcohol in vessels over 55 gallons, or if total capacity exceeds 1000 gallons (not barrels)

*Please note that while partially sprinkling a building is technically permitted by code, it is not advised because many fire department policies include prohibitions to this. Please check with your local authority having jurisdiction. 

Scenarios Where Secondary Containment is NOT required:
(Please note this applies for indoor, closed systems)

Fully sprinklered Building
Over 240 gallons of alcohol over 16% ABV (Will be an H-3 Occupancy)
Alcohol in wooden barrels/ casks

Fully sprinklered Building
Over 240 gallons of alcohol over 16% ABV (Will be an H-3 Occupancy)
Alcohol in vessels under 55 gallons and total capacity not totaling more than 1000 gallons.

Fully sprinklered Building
Under 240 gallons of alcohol over 16% ABV (Need not be an H-3 Occupancy)

Non- Fully sprinklered Building
Under 120 gallons of alcohol over 16% ABV (Need not be an H-3 Occupancy)

What does secondary containment look like?

Secondary containment can be achieved in several different ways. The code does not explicitly give directions on how to do this. This is an example of “performance language”, where the code give you the final goal/ requires you to design a safety feature…and it is up to the designer to make that happen. The code does specify some performance requirements, such as combustibility of materials, permeability of materials, slopes, depths, etc. Generally, we use concrete block or poured in place concrete as the containment material. Please see the IFC for further detail.  We have identified several general design methods to achieve secondary containment as shown in the following diagrams:

How big/ deep does it need to be?

The depth/ containment size is determined based on the volume of the largest vessel, plus 20 minutes of fire sprinkler water over the containment area. The sprinkler water will be determined by a fire protection engineer, but a common sprinkler flow rate for an H-3 room will be .35 GPM/SF.

For an example, a room with a 300 gallon vessel, a containment area of 160 SF, and a sprinkler flow of .35 GPM/SF, will result in a containment depth of 1′-8″.

Below is a real example of a tank room with secondary containment (of a much higher wall):

Thanks for reading! As you can imagine, secondary containment can certainly have some design and budgeting implications, but with proper planning, it can easily be integrated into the construction of a project. It is important to be informed on this topic when beginning to store larger vessels of alcohol at your facility. We hope you learned some important concepts here that can help lead you in the right direction if and when you may require secondary containment at your facility!

Article by:

Matthew Taylor-Rennert

Dalkita Architecture & Construction