Sprinklers, fire protection and what you are allowed to store

The fire protection system is the least visible thing in a bay and the most likely to constrain what you actually do there. It is designed for a specific set of assumptions about what is stored, how high, and in what configuration. Change those assumptions and the system may no longer be adequate — which is a code problem, an insurance problem and a safety problem at once.

The variables that decide the design

• Commodity class — how readily what you store burns and how much heat it releases. Plastics, aerosols, foam and flammable liquids sit at the demanding end; metal parts and non-combustible goods at the easy end.
• Storage height — how high the top of storage sits, not how high the roof is.
• Storage arrangement — on the floor, on pallets, in single- or double-row racking, in solid-pile or shelf storage. Racking with solid shelves behaves very differently from open racking.
• Packaging — cartons, wrapping and plastic packaging can raise the commodity class of otherwise benign goods.
• Aisle width — narrow aisles allow fire to spread across them more readily.

What this means in practice

A bay whose sprinkler system was designed for ordinary-hazard storage to a modest height will not lawfully or safely support high-piled storage of plastics, whatever the clear height allows. The physical space is there; the protection is not.

This is a real constraint with real consequences. Insurers ask about it, municipalities enforce it, and a mismatch discovered after a loss is a very bad place to be. It is also completely manageable if you ask the question early.

Questions to ask before you sign

1. Is the building sprinklered? Some older industrial buildings are not.
2. What was the system designed for — what commodity class, what storage height, what arrangement?
3. Is there a design or hydraulic calculation on file, and can I see it?
4. Does my intended storage fall inside that design?
5. If not, what would an upgrade involve, who pays, and is the water supply adequate for it?
6. What does my insurer require, and does it differ from what the code requires?

Get the answers in writing, and put your intended use in the offer. A landlord who confirms the space suits your stated use has given you something to rely on.

In-rack sprinklers and ESFR

Where ceiling sprinklers alone cannot protect the storage, the answer is either in-rack sprinklers — heads within the racking itself — or an ESFR system, a ceiling system using large-droplet heads designed to suppress a fire rather than control it. Both are expensive, both constrain the rack layout, and ESFR in particular imposes rules about what may be hung below the heads.

In-rack sprinklers also mean the racking is now part of the fire protection system, so rearranging the racks becomes a fire-protection change rather than a Saturday job.

The rest of the fire protection picture

• Extinguishers — required, with a type and distribution matched to the hazard, and inspected on a schedule.
• Alarm and monitoring — most sprinklered buildings have monitored flow and tamper switches. Check who holds the monitoring contract and who is called.
• Exits and travel distance — racking changes travel distances. A rack layout that blocks or lengthens an exit route is a code problem.
• Hazardous materials — quantity limits, storage cabinets, separation and spill containment all follow from what you keep on site.
• Hot work — welding and cutting usually require a permit procedure under the lease and the insurance policy.