The warehouse of the future… today: Navigating today’s fire sprinkler requirements for warehousing utilizing ASRS without breaking the bank

In a world of an ever-increasing demand for instant product delivery, automated storage and retrieval systems (ASRS) are being used to increase efficiency across a wide range of warehouse operations by utilizing cutting-edge robotics. However technically advanced they may be, ASRS systems are certainly not without significant potential fire safety risks. The rapid development of these systems has outpaced the coverage provided within the current building and fire codes and associated referenced standards. Many of these systems are simply outside the scope of the established protection metrics, which are based on conventional storage methods.

As a result, the selection of protection criteria has turned to using insurance-driven mandates to address the potential risks associated with these installations. This has resulted in a number of prescriptive mandates that can add significant costs to a project. Factors that influence facility fire safety and total installed costs can include container types (trays, open-top versus closed-top), container materials (noncombustible, plastic, cellulosic), container ventilation (ability to release water), flue spaces/aisles (openness versus closedness of the array), and storage height as well as the specific commodities being stored.

This article will explore appropriate fire protection, including installation criteria, for a variety of ASRS arrangements, and highlight opportunities for more economical solutions.

Recent ASRS fires and an urgent need for protection

A quick review of recent warehouse fires illustrates the urgent need for appropriate fire protection in these facilities. For example, the Ocado Warehouse Fire engulfed the online supermarket’s warehouse outside of London in July 2021. This blaze was ignited when three automated grocery picking robots collided. Fortunately, no one was injured; however, the fire ultimately cost the company tens of millions in lost revenue.

This was not the first warehouse fire for the robotic warehouse pioneer. In February 2019, the company’s Andover facility was the site of a massive blaze caused by an electrical fault with a robot, which required 200 firefighters and 20 fire engines to douse.

The impact of ASRS on fire safety simply cannot be overstated. And, while warehouse fires such as these are unlikely to sound the death knell of automated warehouses, addressing appropriate fire protection is absolutely vital.

Which factors most influence warehouse fire safety?

Automated storage and retrieval systems, or computerized robotic-aided material handling systems, are designed to efficiently store and retrieve items. But several factors — including limited flue spaces, tote/product array areas greater than 20 square feet, open-top containers and exposed non-expanded group A plastic — can greatly influence facility fire safety as well as total installed cost for warehouses that utilize ASRS.

Limited flue spaces/large shielded arrays — In an effort to improve the efficiency of the storage array and capitalize on the accuracy with which the robotics can move and place products, the available space between stored items is getting smaller. This tighter spacing of stored items results in larger shielded areas, which restrict the ability to get water to the seat of the fire within the storage array, making it more difficult to control a developing fire with installed fire sprinklers.

Open-top containers — The use of open-top containers to store materials provides for efficient placement and picking from the container, enhancing efficiency. However, the open-top nature of these totes will tend to collect discharged water from the installed fire sprinklers, making it more difficult to control a developing fire.

Exposed non-expanded group A plastic — The introduction of plastic totes as a common material-handling component in many of the ASRS systems represents a significant increase in the fuel loading and hazard associated with the storage array, making the protection of such storage even more difficult.

Large expansive storage systems — The drive for efficiency in the use of the available cubic volume of storage space has led to massive storage arrays. These can pose a significant difficulty to arriving fire service personnel.

Opportunities for more economical solutions

Through a comprehensive and rigorous test program, answers to the most pressing fire protection questions can be determined. Properly conducted, fire testing results in innovative solutions that address situations such as automated warehouses, where prescriptive answers are not always the best — or economical — option.

Specifically, full-scale fire testing provides vital solutions for the unique challenges of warehouses utilizing state-of-the-art robotics. This testing results in equivalent performance-based approaches, where prescriptive code compliance is not feasible due to process requirements, historic fabric or existing conditions.

Full-scale fire testing also examines difficult-to-protect commodities, storage or display arrangements, rack configurations and more. Fire testing is a vital component to solving complex issues such as solid shelves, blocked flues and aisle limitations. The use of such testing is recognized in general accordance with NFPA 13, Chapter 24, Alternative Sprinkler System Designs, and allowed as an alternate, material and method.

Conclusion

While ASRS systems can pose significant safety risks, warehouses are unlikely to abandon this cutting-edge technology. Therefore, the impact of ASRS on fire safety must be addressed through innovative, new solutions, which can rise to these new challenges. Full-scale fire testing delivers insightful analysis, which influences issues such as container types, ventilation and specific commodities, resulting in both appropriate protection and cost-efficiency.