Warehouse Racking Changes and Fire-Protection Design

Updated 6 Oct 2026 · 11 min read · by Secured Engineers Editorial Team

Two engineers in hard hats look up at tall warehouse racking holding cartons, shrink-wrapped pallets, plastic drums and bulk bags, with red sprinkler mains along the ceiling and a hose reel on the wall. — Concept illustration made for this page with an AI image tool — not a photograph of a Secured Engineers project.

Racking is bought as a warehousing decision: more pallet positions in the same shed. For the fire-protection system it is a change to the design basis. Sprinkler protection for a store is worked out from what is stored, how it is packed, how high it is stacked and in what arrangement. Raise the racking or change what sits on it, and the sprinklers, the fire pump and the tank may be protecting a warehouse that no longer exists.

This guide covers the four inputs that decide the fire design (the goods and their packaging, the storage and roof heights, the approved design you are changing, and the aisles and water supply), with a checklist and a decision table to use before the racks are ordered.

Why storage decides the sprinkler design

The National Building Code of India 2016 (NBC 2016, published by the Bureau of Indian Standards) classifies buildings by occupancy for fire safety in Part 4: storage buildings are Group H, hazardous buildings Group J, and industrial buildings are divided by hazard into G-1 to G-3. In Indian practice sprinkler systems are designed to IS 15105, the BIS code of practice for automatic sprinkler systems, unless the authority or the insurer specifies another standard. Its current edition is the 2021 first revision.

IS 15105 treats storage as a hazard in its own right. The category of goods, the height and method of storage, the aisles between stacks and the size of each storage block decide the design density, the area the system must cover at once, and whether sprinklers are needed inside the racks as well as at the roof. All of these can change without a single fire drawing being issued.

1. Commodity and packaging: what is actually on the pallets

The fire hazard comes from the goods and their packaging, not from the name on the building. Steel fittings in cardboard on timber pallets are a different fire from the same fittings shrink-wrapped with foam inserts on plastic pallets. Expanded plastics and foam, plastic crates and idle pallets, rubber and tyres, aerosols, flammable liquids and lithium-ion batteries are the usual reasons a storage hazard rises. Where different goods share a building, the design is normally governed by the most hazardous storage unless it is segregated.

Record the commodity before anyone classifies it, and keep the list as a register: the product mix tends to change faster than the fire design.

Record this	Why the fire design needs it	Where it usually comes from
Products stored in each zone, by volume	Sets the category of goods the designer classifies	Warehouse management system or item master: the top lines by pallet count
Packaging: cartons, shrink or stretch wrap, foam inserts, plastic trays or crates	Packaging can put a low-hazard product into a higher category	Packaging specifications and a photograph of a typical pallet
Pallet material, and where idle pallets are kept	Idle pallets, timber or plastic, are a storage hazard of their own	Pallet count by type; the idle-pallet area on the layout
Aerosols, flammable liquids, gas cylinders, chemicals	May need segregation, special protection or a separate licence beyond ordinary storage design	Safety data sheets and the quantities held
Lithium-ion batteries, as stock or inside products, and forklift battery charging	A hazard the designer, the authority and the insurer must agree an approach for	Product data; the charging area on the layout
Tyres, rubber, foam and expanded plastics	Usually classified among the more hazardous storage categories	Item master and stock counts
Storage temperature: ambient, chilled or frozen	Water-filled pipes can freeze, which changes the type of sprinkler system	Operating temperature of each chamber
Expected change in product mix over the next few years	The design should cover the goods you will store, not only today's	Sales and operations plan; new client contracts for a 3PL

2. Rack and roof heights: storage height is a design input

Storage height is measured to the top of the stored goods, not the top of the rack frame, and read against the roof above. Four things matter together:

Height of storage for each category of goods. The sprinkler code sets the protection for each combination; above certain heights a storage area is treated as a higher hazard.
Clearance between the goods and the sprinklers. Sprinklers need space to develop their spray pattern. Stacking into that space reduces protection with no visible change to the system, so mark the maximum storage line on racks and walls.
Roof shape and height. Under a sloped shed roof the sprinkler-to-goods distance varies across the bay; the design has to work at the worst position.
Storage method. Block stacking, selective, double-deep, drive-in and very-narrow-aisle racking, solid-deck shelving and mezzanine pick towers each behave differently in a fire. Solid shelves and mezzanine floors obstruct roof sprinklers and usually need sprinklers beneath them.

When rack storage goes beyond what roof sprinklers can protect for that category of goods, the code calls for intermediate (in-rack) sprinklers. That changes the racking specification too: room for in-rack pipework, flue spaces between pallets kept open, and pipes guarded against forklift impact. Decide it before the racks are ordered; fitting in-rack protection into loaded racks usually means emptying them in sections.

3. Re-check the approved sprinkler design before the racks are ordered

The useful question is whether the proposed storage still falls inside the design basis that was approved and built. Work through it in this order:

Find the design basis. From the approved fire drawings, the hydraulic calculation and the fire NOC conditions, note the hazard class, design density, area of operation, storage height and method assumed, and the pump duty and tank capacity provided.
Describe the proposal. Rack layout and elevations, beam levels, top-of-storage height, flue spaces, aisle widths and block sizes, with the commodity checklist.
Classify the proposed storage against the edition of IS 15105 your design and authority use. If nothing moves, record the check in the fire file.
If the basis changes, re-run the hydraulics for the new density, area and any in-rack demand, then check the pump duty point and the stored water.
Coordinate the drawings. Rack and sprinkler drawings must agree on uprights, beams, in-rack branch lines, lights and exit signs.
Settle the approval route. Ask the fire authority whether the change needs a revised approval under the state's rules, and tell your insurer. Neither answer can be assumed; see changes a fire NOC may no longer cover.
Install, test and record. Flushing and pressure tests, a flow test at the most demanding area, and as-built drawings stating the new storage limits.

The sprinkler calculator gives a first head count for budgeting a layout; storage protection with in-rack sprinklers needs the designer's hydraulic calculation. Design and approval drawings for this kind of change sit under design and statutory approvals, the installation under fire-fighting systems.

4. Aisles, access and the water supply

Aisle width and block size. Narrower aisles and larger storage blocks can raise the protection a storage area needs, and very narrow aisles change how firefighters and hose reels reach the stock.
Hydrants, hose reels and exits. New rack runs must not block hose reels, hydrant valves, exits or the routes to them. Exit routes and travel distances are part of the NBC 2016 Part 4 means-of-egress requirements.
Water supply. A higher density over a larger area, plus any in-rack demand, means more flow at higher pressure for longer: a bigger pump duty and more stored water. Fire water is stored for firefighting only, never shared with domestic or process water. The fire water tank calculator frames the storage; planning fire pump capacity covers the pump.
Detection, smoke and venting. NBC 2016 Part 4 also covers smoke control and venting in industrial buildings. Taller, denser storage changes where smoke collects and how detectors and vents perform. For day-to-day heat and fumes, see warehouse ventilation for expansion and new storage uses.

Decision table: what a racking change can trigger

Proposed change	What it can change in the fire design	Before you commit
Taller racking, same goods	Storage height passes the design basis; the storage may move to a higher hazard; in-rack sprinklers; more pump duty and stored water	Re-run the hydraulics at the new top-of-storage height before ordering racks
Same racking, new goods or packaging	Category of goods changes; segregation or special-hazard protection may be needed	Have the designer classify the new mix; ask the authority about any separate licence
Block stacking replaced by pallet racking	Storage method, flue spaces and the in-rack requirement change	Coordinate the rack layout and the sprinkler layout as one drawing set
Very narrow aisles or larger storage blocks	Aisle and block limits in the sprinkler code; hose-reel reach; travel distance to exits	Check aisle widths, block sizes and exit routes against the design
Mezzanine, pick tower or solid shelving	Obstructs roof sprinklers and usually needs sprinklers below; adds floor area and changes exit routes	Treat it as a building change with its own fire drawings
Chilled or frozen storage	Freezing risk to water-filled pipes; insulated panel construction	Designer selects a suitable system type; check the fire performance of the panels
Goods stacked closer to the roof	Less clearance below the sprinklers than the design assumed	Mark the maximum storage line on racks and walls, and enforce it
More forklifts and battery charging	Charging-area hazard; impact risk to in-rack pipework	Keep charging away from high-hazard stock; guard in-rack pipes

Planning racking, a new storage use or an expansion? Share the facility use, the proposed racking and the approved fire drawings through a scope request, so the design check starts from your documents. The wider storage scope is covered under warehousing and logistics, and more planning guides are in Insights.

Sources and how to verify

Bureau of Indian Standards, National Building Code of India 2016 (SP 7:2016), Part 4 Fire and Life Safety: occupancy classification, fire-fighting installations, means of egress, smoke control and venting.
Bureau of Indian Standards, Guide for Using National Building Code of India 2016: summary of the Part 4 occupancy groups (G Industrial, H Storage, J Hazardous) and the fire installations the Code covers.
Bureau of Indian Standards, IS 15105:2021, Design and Installation of Fixed Automatic Sprinkler Fire Extinguishing Systems: Code of Practice (first revision), Fire Fighting Sectional Committee CED 22.

Confirm locally: which edition of IS 15105 your design and your state fire service apply (designs approved before the 2021 revision will have used the 2002 edition, if they followed IS 15105), whether your change needs a revised fire approval, and any storage conditions in your insurance policy or surveyor's report. NBC 2016 is a model code; it applies through the authority that adopts it.

Frequently asked

What should I record about the stored goods before a racking change is designed?

The products in each storage zone by volume, how they are packed (cartons, shrink-wrap, foam inserts, plastic crates), the pallet type and where idle pallets are kept, any aerosols, flammable liquids, gas cylinders or lithium-ion batteries, the storage temperature, and the product mix you expect over the next few years. Together with the proposed rack elevations, that is what a designer needs to classify the storage. The checklist in this guide lists each item and where it usually comes from.

Which warehouse conditions turn a racking change into a bigger fire-protection job?

Storage height above what the approved design assumed, a move to more hazardous goods or packaging, little clearance between the goods and the roof sprinklers, very narrow aisles or large storage blocks, mezzanines and solid shelving, chilled or frozen chambers, and a fire pump or tank with no margin left. Any one of these can add in-rack sprinklers, a larger pump or more stored water to the scope. Doing the work in a live, loaded warehouse adds sequencing and access cost on top.

What should I send a fire engineer to check a proposed racking layout?

The approved fire-protection drawings and the fire NOC with its conditions; the hydraulic calculation or as-built drawings if you have them; fire pump and tank details; the racking supplier's layout and elevations showing beam levels and the top-of-storage height; the completed commodity and packaging checklist; a roof section; and any recommendations from your insurer's survey. With those, an engineer can say whether the change stays inside the design basis or what it adds.

Does a racking change need a fresh fire NOC?

There is no single national answer. Fire approvals are granted by the state fire service or the local fire authority against the building, its occupancy and the fire scheme that was approved, and the rules differ from state to state. If the change takes the storage outside the approved design, ask the authority in writing whether a revised approval is needed and keep its reply with the fire file. Do not assume the answer either way.

We are a tenant installing racking. What should we settle with the landlord first?

Who checks the racking against the building's approved fire design, who applies to the fire authority if a revised approval is needed, who pays for any sprinkler, pump or tank upgrade, and who keeps the records afterwards. Agree it in writing before the racks are ordered. The lease and the authority's rules decide the legal position; this is a planning list, not legal advice.