Phone: (844)OC-LABEL (844)625-2235


Is Flue Space Enforcement Required?

Requirements for Flue Space Enforcement is a decision that differs between jurisdictions. Some jurisdictions require Flue Space Enforcement, some do not. Of those that do require it, they may have certain additional requirements as to the methods permitted or conditions for certain methods to be used. Check with your High Piled Storage Permit Consultant to find out what flue space enforcement requirements are in place for your project.

What are the Requirements for Flue Spaces?

The Fire Code has different clearance requirements for flue spaces. In a nutshell:

  • Single Row racks require minimum 3” Transverse flue spaces. There is no Longitudinal flue space requirement.
  • Multiple Row racks require minimum 6” Transverse flue spaces. There is no Longitudinal flue space requirement.
  • Double Row racks have a complicated set of flue space options. Check with your High Piled Storage Permit Consultant to get the most efficient flue space options for your project. In a nutshell, the 2 options are:

Option #1: Minimum 6” Transverse flue spaces required. There is no Longitudinal flue space requirement in this case. Storage Height limited to 25’-0” high maximum for this Option.

Option #2: Minimum 3” Transverse flue spaces required. Minimum 6” Longitudinal flue spaces required.

In addition to the minimum width requirement, all High Piled Storage over 25’-0” high is also subject to Vertical Alignment. This means that the flue spaces between loads have to be aligned. When loads are less than or equal to 25’-0” variance in flue space locations is permitted.

What’s the Difference Between Requirement and Enforcement?

Required Flue Spaces are driven by Fire Code requirements for High Piled Storage. The Requirement addresses the minimum clearances between loads that are required (Flue Spaces). This clearance is required to exist whether or not Enforcement of that Requirement applies to your particular jurisdiction!

Enforcement is an allowance in the Fire Code that gives authority to the local jurisdiction to require a mechanical or visual device to make flue spaces maintained. Sometimes these devices are steel members, and other times they are Flue Labels, and some jurisdictions require a mix of the two enforcement methods.

A jurisdiction’s position on Flue Space Enforcement is largely driven by the community’s historical ability to maintain flue space clearances without Enforcement, or the ability for the local jurisdiction to require inspectors to manage flue spaces via citation/violation enforcement, risk research associated with the performance of different enforcement devices, and the economy and costs associated with requiring the different methods of Flue Space Enforcement.

What Other Flue Space Enforcement Alternatives are Out There?

The following are other typical methods of Enforcement. This list is by no means exhaustive nor implicative that other methods exist or can be employed upon approval from the Authority Having Jurisdiction:

Pallet Stops:

These steel devices come in a few formats (Traditional Rollform Pallet Stops, “WorldStop”, etc.) These devices only enforce the Longitudinal flue space.

Flue Keepers:

These steel devices protect the Transverse Flue Space at Storage Rack column locations

Flue Labels:

These devices maintain a visual means of Flue Space Enforcement at Storage Rack column locations and at interior beam locations.

What is the difference between enforcement at the column and enforcement at intermediate locations between loads on the beam?

There is no difference in flue space requirements at either of these locations– they are both required to meet the minimum Transverse flue space Requirement (3” or 6” as provided on your High Piled Storage Plan).

What device is permitted at which location varies by jurisdiction:

  • Some jurisdictions require a mechanical device at the column locations but no Flue Labels at interior beam locations
  • Other jurisdictions require both a mechanical device at the column locations AND Flue Labels at interior beam locations
  • Other jurisdictions allow Flue Labels to be present at both column and interior beam locations

What do I do if my loads are not on pallets?

This is a great question to ask your High Piled Storage Permit Consultant  for your specific situation. However, as a general rule, all loads and beam lengths selected must be arranged such that the minimum Flue Spaces can easily exist in all product configurations, regardless of varying load size. This can lead to a deeper discussion with your HPS Consultant on different configurations and case-scenarios.

How does my decision in the Transverse Direction Affect the Longitudinal Requirements?

This is another great question to ask your High Piled Storage Permit Consultant  for your specific situation. There are some combinations of Flue Space and Enforcement techniques that can provide the most optimal layout.

 Why Should I Choose Flue Labels Over A Steel Device If the Jurisdiction Permits Both a Flue-Label-Only Option and A Steel Device Option?

This question usually comes down to cost. The cost for a Flue Label is orders of magnitude lower than the cost of a steel device to mount on the racking structure. Please note: This only applies in jurisdictions that permit both methods!

Why order Flue Labels from

We are experts in high piled storage and Creative-Compliant Flue Space Design and have gotten approval in every single jurisdiction our custom Flue Labels have been applied to. Our Flue Labels are the industry standard!

About Us

Label Conformance is an Orange County-based company that supplies flue space labels to meet high piled storage code regulations in jurisdictions that support the flue label method of visual enforcement.


Label Conformance (dba OC Labels)
10 Hughes #A207
Irvine, CA 92618
Phone: (844) OC-LABEL (844) 625-2235