Inventory Management and Warehouse Operations.


Warehouse Fire Safety

By Dave Piasecki

When companies think about warehouse fire safety, they usually think of compliance to fire codes and OSHA regulations.  While compliance is a good starting point (and is obviously mandatory), there is more to warehouse fire safety than compliance.  Below are a few misconceptions about warehouse fire safety.

  • My warehouse just passed a fire inspection therefore it must be up to code.
  • My warehouse is up to code therefore it must be safe.
  • My warehouse was designed with a sprinkler system therefore it can’t burn down.

I must admit that like many other warehouse professionals I spent many years taking this “ignorance is bliss” approach to fire safety.  As much as we all talk about safety coming first, safety projects rarely rate high on our prioritized project lists.  The difficulty in obtaining applicable safety and compliance information and the fear of opening a “can-o-worms” by using outside help combined with the fact that you may have just passed a fire inspection makes it easier to justify perpetuating ignorance of safety issues.  And certainly most companies can operate under these conditions and never have a serious fire.  Unfortunately, some companies will have a serious fire and the difference between a small financial loss and a catastrophic loss with the potential for loss of life will come down to the level of fire safety knowledge and the application of that knowledge to warehouse design and operational practices.

Fire inspections can vary significantly from one jurisdiction to another and from one inspector to another.  An inspector in a primarily residential community will likely not be as knowledgeable in the codes related to high-piled storage as an inspector in an industrial area.  An inspector that’s been involved in fighting a large warehouse fire will likely have a higher sensitivity to certain issues than one that has not had the same experience.  Generally, fire inspections are looking for housekeeping-type hazards such as blocked exits, blocked aisles, damaged sprinkler systems, missing or neglected fire extinguishers and exit lights, accumulations of flammable debris, or misuse of electrical equipment such as extension cords.  A fire inspector can’t possibly inspect and evaluate the hazard classifications of all the product stored and verify the engineering specifications of a sprinkler system on a walk through inspection. If you’ve made changes to the composition of the products being stored, the types of packaging used, or the storage configuration, it is unlikely that the inspector will be aware of this unless you bring it to his or her attention.  And when is the last time you volunteered to give unsolicited information during an inspection.

Fire codes are designed to achieve a minimum level of safety; even though the level of detail in the codes is extensive they can’t possibly cover every hazard or combinations of hazards.  To use traffic laws as an analogy, just because you are obeying traffic laws does not mean that you will not get into an accident.  The same is true of fire codes; they are designed to reduce the opportunities for fires to start, reduce the opportunities for fires to spread, provide for evacuation of occupants, and provide access for fire fighters to extinguish the fire.

Sprinkler systems are engineered to cover a specific commodity classification in a specific storage configuration.  Changes such as introducing a new product line, using a different packaging material, or changing from wood pallets to plastic pallets can increase your hazard classification and render your sprinkler system inadequate to control a fire.  Also, changing the size of pallets or the way product is stacked in racking can infringe on flu space requirements, reducing the ability of the sprinkler system to control a fire.  It’s also a common misconception that sprinkler systems are designed to extinguish fires.  Although they can be designed to extinguish fires, systems designed to meet minimum code requirements are only expected to help control the spread of the fire until the fire department arrives to extinguish it.  The fact is, every year buildings with inadequate sprinkler systems burn to the ground.

So how do you determine the level of fire protection your warehouse has/needs?  I recommend a combination of a little education and employing the services of a fire protection engineer.  Interpreting fire codes can get very complicated and evaluating your system’s engineering is not a do-it-yourself project. However, having someone on staff with some basic knowledge of the fire codes will help you ensure you get the best results from working with a fire protection engineer and allow you to quickly identify when operational changes may compromise the original fire protection design.  Balancing safety issues with operational issues is rarely a simple task. An overly cautious fire protection design may result in significant loss of storage capacity, high costs, or create ongoing maintenance issues (such as those related to in-rack sprinklers) without necessarily reducing your exposure to hazards. While an under designed system could mean loss of life and property.

Intro to fire codes. 

The best way to become familiar with the fire codes is to read the codebooks.  If there is a fire codebook written for amateurs, I am unaware of it, so you’re going to have to spend some time learning to navigate the actual codebooks and interpret the codes.  To make this a little more confusing, there are a number of organizations that publish fire codes.  Individual states and municipalities will then adopt the codes put out by a specific organization.  In addition, the states or municipalities can also amend the codes they adopt to include additional codes.  There are also a lot of provisions left up to the discretion of the local fire chief.  Just a note:  In the event of conflicts interpreting the fire code, the fire code is “whatever the local fire chief says it is”. 

Recently the Building Officials and Code Administrators International, Inc (BOCA), International Conference of Building Officials (ICBO), and Southern Building Code Congress international, Inc. (SBCCI) got together forming the  International Code Council (ICC). This new organization put out the 2000 International Fire Code (2003 International Fire Code is now available) in an effort to standardize the fire codes .  For educational purposes I would recommend using this code.  For the most part, all of the various codes are similar and since you should be using an expert for the detailed evaluation, I think this should be sufficient.  You will find in going through the codes that in certain cases you may be referred to a separate publication for additional code information such as publications put out by the National Fire Protection Association (NFPA) on specifications for sprinkler systems or storage of aerosols. 

While the codebooks may at first seem confusing, you can obtain a good overview of the key requirements fairly quickly.  You will also quickly learn why you will need expert help when it comes to the details of determining hazard classifications and code requirements.  For information relating to warehousing, the best place to start is the section on High-Piled Combustible Storage.  Generally, high-piled combustible storage codes apply to floor or racked storage exceeding 12 feet in height, however, at the discretion of the fire chief, the codes may also apply to high hazard commodity storage exceeding 6 feet in height.  The codes use the combination of commodity hazard classifications, size of storage area (square footage), maximum storage height, material handling methods, and storage configurations (solid-piled storage, racked storage, shelf storage, decking type, storage height, etc.) to determine sprinkler density, flue space requirements, aisle widths, as well as the need for building access, smoke and heat removal systems, curtain boards, fire walls, and in-rack sprinklers.

The following are some code requirements and recommendations that apply to many warehouse operations.  I’ll again note that specific code requirements will vary depending upon your municipality and storage characteristics.

  • Although some smaller warehouses may not legally require them, automated sprinkler should be considered as standard requirement in any warehouse.
  • Storage should be maintained at least 18 inches below sprinkler head deflectors or 24 inches below ceiling (for buildings without sprinklers). ESFR sprinklers may require 36 inches of clearance .
  • In racked storage, transverse flue spaces of at least 3 inches should be maintained.  Transverse flue space is the space to either side of a racked pallet (6-inches may be required for deeper rack, taller rack, or if no longitudinal flue space is used).
  • In racked storage, longitudinal flue spaces of at least 6 inches should be maintained.  Longitudinal flue space is the space between the rows of back-to-back rack.  The requirement for longitudinal flue space can vary based on rack height and transverse flue space. For example, for racking under 25-feet in height, you may not be required to have longitudinal flue space, but without the longitudinal flue space you may be required to have 6-inches of transverse flue space (rather than 3).  It is important to note that the flue space is measured as the distance between the loads, not the distance between the racks. In a standard pallet rack configuration you will usually have 3 inches of pallet overhang, calculating this into the flue space would require the rows of rack to be at least 12 inches apart.
  • Most warehouses meeting the above flue space requirements do not require in-rack sprinkler systems.  Racking with solid decking, larger loads, storage configurations that prevent maintaining the flue spaces, storage of high hazard materials, or storage greater than 40 feet in height will probably require in-rack sprinklers.
  • Dead end aisles must not be more than 50 feet in length.
  • In solid piled floor storage there must be an aisle at least every 100 feet and within 50 feet of walls when materials are stored against the wall.  Essentially this means that any portion of the solid piled storage should be within 50 feet of an aisle.
  • During restocking operations using manual stocking methods (using stock carts, rolling ladders, etc.) a minimum unobstructed aisle width of 24 inches or ½ the aisle width, whichever is greater, must be maintained.
  • During mechanical stocking operations a minimum unobstructed aisle width of 44 inches must be maintained.
  • Automated material handling equipment such as carousels and ASRS units will have additional code requirements to prevent the equipment’s motion from spreading a fire.
  • Smoking is prohibited in warehouses and no smoking signs are required.
  • Battery charging areas have specific code requirements including ventilation, acid neutralization, eye wash stations, and spill control systems.
  • Liquid Propane fuel cylinders used on LP forklifts should not be stored within 20 feet of fire exits and are limited to a maximum quantity of 300 lbs per storage location.  This is the equivalent of six 43 lb cylinders or nine 33lb cylinders.  Empty cylinders are considered full for this calculation. If additional storage locations are required they must be separated by a minimum of 300 feet.
  • One word: Plastics.  Plastic content is the single storage characteristic most likely to contribute to a class IV or Class V high-hazard commodity classification.  The classification is based upon the type of plastic and the overall content, measured by percent by weight for unexpanded plastics and percent by volume and weight for expanded plastics.  This is where operational changes such as changing packaging materials from paper based to polystyrene or changing from wooden to plastic pallets can have a substantial impact.
  • Another word:  Aerosols.   “Rocketing” is a term used to describe the ability of aerosol containers to propel themselves across a warehouse, carrying a trail of fire behind them.  There is a whole series of codes dedicated to the storage requirements for aerosol products.  Depending upon the chemical content and the amount of aerosols stored (measured by weight), separation areas, chain-link fence enclosures, fire walls, and additional sprinkler protection may be required.
  • One last word:  Hazardous Materials.  Flammable liquids, solids, and gasses, explosives, oxidizers, and reactive materials fall under the category of Hazardous materials and have their own series of codes that apply.  You’re definitely going to need some expert guidance when storing these types of materials.

Obviously there are a lot of other code requirements including basic fire safety requirements such as not blocking fire exits and maintenance and placement of portable fire extinguishers.  And, in addition to the fire codes you may also be subject to OSHA and EPA regulations.

Beyond Compliance. 

As previously mentioned, compliance is only intended to provide a certain minimum level of safety.  When working with a fire protection engineer you will likely want to incorporate additional safety measures.  When designing a new system it is also recommended to investigate installing a design capable of handling a higher hazard classification. Should your product line or storage needs change in the future it can be very expensive to change your existing system to accommodate the higher hazard classification.  There are also a lot of operational issues that relate to fire safety that should be considered.  Like everything else in your operation, the level of fire safety will be greatly impacted by the procedures and training provided to the employees.

  • Evacuation Plans.  It is extremely important to make it absolutely clear to employees what they are expected to do in the event of a fire or the sounding of the fire alarm.  The most common reaction by employees to the fire alarm sounding is to look to their supervisor to see if they should leave the building, or look to other employees to see what they are doing.  Employees should be informed that whenever they hear the fire alarm they should immediately leave the building unless they have been given previous notification of an alarm test.  It should also be made clear that they should leave through the nearest exit.  Warehouse workers are usually not stationary so assigning a specific exit rarely applies.  I recall an employee during a drill walking across the entire warehouse, passing several fire exits on his way to his “assigned” exit.  Now I would certainly hope that had the employee seen an actual fire, he would not have walked into it to get to his assigned exit, but “you never know”.  Also, if employees are required to perform certain tasks prior to leaving the building, such as shutting down a piece of equipment, they should be given specific instructions on the task and also under what conditions they should perform the task and under what conditions they should immediately evacuate.
  • Fire Extinguisher Training.  Employees should be trained on the use and locations of fire extinguishers.  This is especially true of employees working in areas where there are known ignition sources.
  • Trash Accumulation.  Large accumulations of trash and debris can be a potential fire hazard as well as a hindrance to evacuation.  Adequate containers should be provided and specific duties assigned for removing the trash as containers fill.  There should also be designated areas for storage of pallets, crates, etc.  It’s also a good idea to limit the stack height of loose pallets to six feet.
  • Designate floor storage and staging areas.  Using tape or paint to designate floor areas approved for storage or staging of materials will make it easier to enforce safety issues related to blocked aisles etc.
  • Incorporate safety training into your regular operational procedures and training.  Safety procedures and training are often handled as a separate issue.  You’ll find it more effective to incorporate safety procedures into your specific task procedures and training.  Issues related to clear flue spaces, sprinkler clearance, aisle clearances, evacuation plans, battery charging and propane cylinder handling should be part of the employee's regular training program.
  • Maintain open communication with your local fire department.  Make sure the fire department is aware of the additions of high hazard materials to your warehouse or changes in storage configurations.  If you do have a fire it’s extremely important that the fire fighters know what they are walking into.
  • Make sure additional precautions are taken during construction and maintenance projects.  If you have contractors working in or around your building, make sure additional measures such as additional fire extinguishers are used, especially if work is being done on a roof or other area where fire extinguishers are not present.  Also make special plans if you have to shut down the sprinkler system for any reason.  You may need to shut down certain operations, provide supplemental fire protection, or provide physical 24 hr monitoring of the building during this period.

Maintaining an environment that provides safety to occupants and reduces the risk of property loss requires not only the initial system engineering, but also attention to safety in day-to-day operational practices and the knowledge of when operational changes may require re-evaluation of your fire protection systems.  

Your Local Fire Department Needs You.

Budgetary constraints often make it difficult for fire departments to acquire all the equipment they need to meet the challenges of protecting lives and property.  While a lack of equipment won't stop the firefighters from fighting fires, it may make it more dangerous for them to do so as well as making it more difficult to save lives.  Local companies can help by contacting their local fire chief to see what types of equipment they are in need of and donate funds towards the purchase of the equipment or actually buy the equipment and donate it to the department.

Go to Articles Page for more articles by Dave Piasecki.

Dave Piasecki, is owner/operator of Inventory Operations Consulting LLC, a consulting firm providing services related to inventory management, material handling, and warehouse operations. He has over 25 years experience in operations management and can be reached through his website (, where he maintains additional relevant information.

BookBook Banner02