Phone: (844)OC-LABEL (844)625-2235


Disclaimer: The article below is written in the context under assumption that flue spaces are required. There are certain conditions where flue spaces are not required. Discuss those options with your High Piled Storage Permit Consultant 

What is a Flue Label?

A Flue Label is a label, typically with an adhesive backing, with yellow background color and the words “KEEP CLEAR” in red font. The widths of these labels are designed to meet the minimum required Flue Space length. The purpose of Flue Labels is to provide a visual means to warehouse operators and fire department personnel to demonstrate that the minimum flue space between a given pair of loads is not being obstructed.

What is a Flue Space?

A flue space is a space between loads on Single Row, Double Row, and Multiple Row Storage Racks that is required by the Fire Code. This space serves a dual purpose:

To allow heat from a fire to rise up to the ceiling sprinklers above so they can activate and help control or suppress a fire, and
To allow activated sprinkler water to reach the fire load

What is a Transverse Flue Space?

A Transverse Flue Space is the space between loads on rack storage parallel to the loading direction.

What is a Longitudinal Flue Space?

A Longitudinal Flue Space is the space between rows of storage perpendicular to the loading direction with a distance between storage loads not exceeding 24 in. When you think of the Longitudinal direction, think the “LONG” distance down the racking rows!

What Happens If Flue Spaces Are Not Provided Per Code?

When flue spaces are not provided in the minimum required manner, fires have better capability to overwhelm the sprinkler system and activate more sprinkler heads than the system was designed to handle. As more heads are activated, the system shares the available supply with more heads, providing less and less flow to each head, which in turn pushes out less water and increasingly allows the fire to take over.

What is a Load?

A load is any item (commodity, product, equipment, etc.) that is put onto a storage rack shelf or set of beams. The load could be on a pallet, though not necessarily. The most clear definition of a load is “any contiguous item or set of items between required flue spaces”. This definition indicates that if a Flue Space is provided, but not of the minimum length required by the Fire Code, then it is not considered a Flue Space and the adjacent loads are treated as a part of the same load!

What is a Single Row Storage Rack?

A Single Row Storage Rack is a Storage Rack that has no longitudinal flue space and that have a dpth up to 6 ft with aisles having a width of at least 3.5 ft between loads on rack.

What is Double Row Storage Rack?

A Double Row Storage Rack is a Storage Rack that has less than or equal to 12 ft in depth or single-row racks placed back to back having an aggregate depth up to 12 ft, with aisles having an aisle width of a least 3.5 ft between loads on racks.

What is a Multiple Row Storage Rack?

A Multiple Row Storage Rack (also called a Multi-Row Rack) is a Storage Rack that has greater than 12 ft in depth or single- or double-row racks separated by aisles less than 3.5 ft wide having an overall depth greater than 12 ft.

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