FM Global DS 8-34: Top-Loading and Crane-Based ASRS

A top-loading ASRS is loaded from above: the robot runs on overhead rails and places totes into the racking below. A classic crane-based AS/RS uses a travelling crane in a narrow aisle handling pallets. This article covers the FM Global DS 8-34 design rules for both types.

Top-Loading ASRS

• Robot travelling on overhead rails
• Racking and tote positions at the lower levels
• Typical height in the range of 8 to 15 m
• Common in retail back-of-house and cosmetics distribution
• Protection: ceiling ESFR plus sprinklers at the top of each zone

Classic Crane-Based AS/RS

• Travelling crane in a narrow aisle, typically 1 to 1.5 m wide
• Pallet based, with unit loads of around 1,000 to 1,500 kg
• Heights from 15 m up to 40 m
• The standard approach from the 1980s to the 2010s, and still widely in service
• Protection: ESFR plus in-rack sprinklers at every level

Retrofitting Older Installations

• Most crane AS/RS installations from that era were built with CMDA plus in-rack sprinklers
• FM compliance typically requires an ESFR upgrade, or CMSA with in-rack sprinklers at every level
• Retrofit is capital intensive and normally staged around production shutdowns
• The original equipment manufacturer is usually the natural retrofit partner, since rack geometry and crane clearances govern what can be installed

Quick Checklist

• ASRS type identified (top-loading or crane-based)
• Height and commodity class established
• ESFR with in-rack sprinklers, at every level for tall installations
• Aspirating smoke detection provided
• Robot emergency stop and bypass arrangements defined
• Retrofit plan prepared where the existing scheme predates current criteria

Frequently Asked Questions

What is the difference between top-loading and crane-based ASRS for fire protection?

A top-loading system runs the robot on overhead rails above lower-level racking, typically 8 to 15 m high, and is usually protected by ceiling ESFR plus sprinklers at the top of each zone. A crane-based AS/RS uses a travelling crane in a narrow aisle and reaches 15 to 40 m, which normally requires ESFR plus in-rack sprinklers at every level.

Why do older crane AS/RS installations often fail FM criteria?

Many were designed around CMDA ceiling protection with limited in-rack coverage, which no longer matches current criteria for the commodity and height involved. Bringing them into compliance generally means upgrading to ESFR or adding in-rack sprinklers at every level, which is why retrofit is a recurring subject on older automated warehouses.

Why is aspirating smoke detection used in automated storage?

Automated aisles are unoccupied, so a fire can develop with nobody present to notice it. Aspirating detection samples air continuously and gives very early warning, allowing the system to be shut down and the fire service alerted long before ceiling sprinklers would operate at that height.

What operational controls are needed alongside the sprinkler system?

The robot or crane must have an emergency stop and a defined bypass arrangement so it can be halted and, where necessary, moved clear during an incident. Without that, a stalled machine can obstruct access and complicate firefighting in an already inaccessible aisle.

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