A mini-load ASRS differs from a shuttle system: smaller totes and cartons of roughly 10 to 50 kg, heights of 4 to 12 m, and a design built around fast pick and pack. FM Global DS 8-34 applies more flexible rules to mini-load than to shuttle systems.
Mini-Load Configuration
- Crane or shuttle based system handling small totes
- Height of 4 to 12 m, against 15 to 30 m for shuttle systems
- Tote weight of roughly 10 to 50 kg, against 500 to 1,500 kg for pallets
- High pick rates, typically several hundred to over a thousand lines per hour
- Typical applications: e-commerce order picking and cosmetics distribution
Sprinkler Arrangement
- Ceiling: ESFR K200 or K360 depending on storage height
- In-rack: one horizontal level every two to three tiers, against every level on shuttle systems
- Open-top combustible totes: one to two tiers between in-rack levels
- Closed-top metal totes: up to three tiers between in-rack levels
- In-rack heads typically K11.2, positioned per the DS 8-34 tables
Open-Top vs Closed-Top
- Open-top combustible: an open carton or plastic tote with combustible contents — the most demanding case
- Closed-top combustible: a lidded tote, where flame spread is slower
- Closed-top noncombustible: a metal tote, which limits the rate of fire growth
- In-rack spacing can be relaxed as you move from open-top combustible toward closed-top metal
Quick Checklist
- Mini-load height within the 4 to 12 m band
- Tote type identified (open or closed top, combustible or not)
- Ceiling ESFR K200 or K360 selected
- In-rack sprinklers every two to three tiers, tighter for open-top
- Aspirating detection, linear heat detection and robot emergency stop provided
- Arrangement verified against the DS 8-34 tables
Frequently Asked Questions
How does mini-load ASRS protection differ from shuttle ASRS?
Mini-load systems are lower, typically 4 to 12 m against 15 to 30 m, and handle much lighter totes. That allows more relaxed in-rack spacing - roughly one level every two to three tiers rather than at every tier - although the ceiling still needs ESFR protection sized to the storage height.
Why does open-top versus closed-top matter so much?
An open tote exposes its combustible contents directly to the flue space, so fire spreads vertically much faster and water must reach into the array. A closed tote, particularly a metal one, slows flame spread considerably. That is why in-rack spacing tightens for open-top combustible totes and relaxes for closed-top noncombustible ones.
What ceiling protection is used over a mini-load system?
ESFR K200 or K360 depending on the storage height and commodity, applied as ceiling protection above the racking. The exact selection follows the DS 8-34 tables, and the ceiling design must be coordinated with the in-rack levels rather than chosen independently.
What detection is required in an automated mini-load aisle?
Aspirating smoke detection is used for very early warning in an unoccupied aisle, often supplemented by linear heat detection along the racking. The system must also interface with the robot emergency stop so the machinery can be halted when an alarm is raised.
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