AS 1940 vs AS 3780 vs AS 4084: which standard applies?

Three Australian Standards get confused for one another on chemical-handling sites, but they answer three different questions. AS 1940 governs the storage and handling of flammable and combustible liquids. AS 3780 governs corrosive substances. AS 4084 governs the steel racking that holds the load. The shortcut: route by the dangerous-goods class of what is inside the container, then treat the rack as a separate, always-on structural question. This guide gives you a decision flow, a DG-class table, and the rule that stops plastic containers being used outside their limits.

AS 1940 vs AS 3780 vs AS 4084: which standard applies?

Each standard owns a different layer of the same storeroom: AS 1940 owns flammable and combustible liquids, AS 3780 owns corrosive substances, and AS 4084 owns the steel racking the packages sit on. They are not alternatives you pick between — they are layers that stack. A racked pallet of corrosive acid in a shed that also holds solvents is simultaneously an AS 3780, an AS 4084 and an AS 1940 matter, with segregation rules over the top.

• AS 1940 — The storage and handling of flammable and combustible liquids. The controlling standard for Class 3 flammable liquids (and C1/C2 combustible liquids): how much you can store, bunding and spill containment, separation distances, ventilation and ignition control. This is the standard behind every fuel, solvent and paint store.
• AS 3780 — The storage and handling of corrosive substances. The controlling standard for Class 8 corrosives — acids and alkalis: compatible materials of construction, containment, segregation from incompatible goods, and safe quantities. Acids eat steel and concrete, so containment material choice is central here.
• AS 4084 — Steel storage racking. The structural standard: how racking is designed, rated, installed, loaded and inspected so it stays standing. It does not care what is in the package — it cares that the beams, frames and the pallet bridging them can carry the load. It applies to dangerous and ordinary goods alike.

Get the layer wrong and you get the wrong control. Treat an acid store as a flammables problem and you over-spec ignition control while under-spec'ing corrosion-resistant bunding. Treat a rack as a chemistry problem and you forget to check the beam capacity that actually keeps the load off the floor. Route each layer to its own standard.

How do I decide which one governs my load?

Start with the Safety Data Sheet, read off the dangerous-goods class, and route the liquid or substance to its DG standard — then ask separately whether it goes on a rack. The DG class is the single fact that decides AS 1940 vs AS 3780; the racking question is independent and is almost always "yes, AS 4084 too" the moment a package leaves the floor. Work the flow top to bottom:

1. What is the DG class? Open the SDS, find the class in Section 14. Class 3 (or combustible C1/C2) → AS 1940. Class 8 → AS 3780. Other classes (e.g. Class 5 oxidisers, Class 6 toxics) have their own standards — get specialist advice.
2. How much, and in what? Quantity and package type set the bunding and separation tier. Both AS 1940 and AS 3780 scale their requirements with how much you hold and whether it is in drums, IBCs or bulk.
3. Is it going on a rack? If yes, AS 4084 applies on top — confirm the rack's rating and the pallet's racking figure cover the load at your beam span. If it is floor-stored only, AS 4084 drops out but the DG standard still governs.
4. Is anything incompatible nearby? If flammables and corrosives (or other reactive classes) share a space, add the segregation rules — separation distance or a compatible barrier — on top of both standards.
5. Is the container compatible? Confirm the material of construction suits the chemical (HDPE/PP vs the substance) and that the standard permits that container for that class — the plastic-IBC limit below is the common trap.

Five questions, and almost any load lands on the right combination of standards. The mistake that causes most non-conformances is stopping at question one — naming the DG standard but never asking the AS 4084 racking question, so a chemically perfect store fails on a structural rating nobody checked.

Which standard covers flammable liquids?

Flammable and combustible liquids are governed by AS 1940 — the Australian Standard for their storage and handling. It is the controlling document for Class 3 flammable liquids and for the combustible C1/C2 categories below them, covering maximum quantities, bunded spill containment, separation from ignition sources and people, ventilation, and electrical-area classification. If the substance can burn as a liquid, AS 1940 is where you start.

The reason flammables get their own dedicated standard is the fire load: a leak is not just a spill, it is a fuel source and a vapour hazard. So AS 1940 puts heavy weight on containment that holds the spill and keeps it away from ignition. Australia's chemical-safety regulator lists AS 1940 as the standard underpinning compliant storage of flammable and combustible liquids in the workplace (safeworkaustralia.gov.au). The headline containment rule comes from AS 1940 Clause 5.9 — for a store of 10,000 L or less, the bund must hold 100% of the largest container plus 25% of the aggregate stored, not a flat "110%". (The bund-sizing detail is worked through in our AS 1940 bund-sizing guide.)

Which standard covers corrosives?

Corrosive substances — Class 8 acids and alkalis — are governed by AS 3780, the Australian Standard for the storage and handling of corrosive substances. It sets out compatible materials of construction, containment and bunding, segregation from incompatible dangerous goods, and safe storage quantities. Where AS 1940 is preoccupied with ignition, AS 3780 is preoccupied with material attack: corrosives degrade steel shelving, concrete bunds and the wrong plastics.

That is exactly why containment material choice is the heart of AS 3780. A bunded steel pallet that is perfect for diesel is the wrong answer for hydrochloric acid, which will corrode it; a chemically resistant polymer or coated bund is required instead. The same logic reaches the rack: corrosive fumes attack galvanised racking over time, so AS 3780 storage often pairs with corrosion-protected or polymer-faced equipment. Crucially, AS 3780 does not switch off AS 4084 — if the corrosives sit on a rack, the rack is still designed and rated to AS 4084, and the corrosion exposure becomes an inspection-and-maintenance issue under that standard's regime.

Where does AS 4084 racking fit in?

AS 4084:2023 governs the steel storage racking itself — independent of what the racking holds — and it applies the moment a load leaves the floor, dangerous or not. It defines how racking is designed, rated, installed, loaded and inspected so it stays stable in service, and Australia's work-health-and-safety regulator points to it as the basis for safe racking systems (safeworkaustralia.gov.au). The DG standards tell you what may go in the package and how packages are kept apart; AS 4084 tells you the structure can carry them.

The trap is the handoff between the rack and the pallet on it. AS 4084 rates the rack — its beams and frames — but that rating assumes the pallet bridging the beams can carry its load unsupported across the span. A heavy-duty plastic pallet rated 10,000 kg static can be rated only ~2,000 kg racking, because racking removes the floor and the deck has to span an open gap and resist creep over time. Size to the racking figure, not the static headline — the full static-vs-dynamic-vs-racking breakdown is in our plastic pallet load ratings guide. For dense, point-loaded dangerous-goods packages — drums and reagent kegs — also confirm beam span and whether steel pallet-support bars are needed to back the deck up.

What does each standard govern?

The table below routes the common dangerous-goods classes you meet on Australian mining and produce sites to the standard that governs them, with the main control each standard imposes and where AS 4084 layers on. Every figure and clause here traces to the published standard — confirm the specifics for your exact substance and quantity against the current edition and your DG consultant.

Read across each row and the pattern is clear: the first three columns are decided by the chemistry, and the last column is decided by whether the load is on a rack. The chemistry routes you to AS 1940 or AS 3780; the geometry routes you to AS 4084. They are answered separately and then satisfied together.

Can a plastic IBC or bin store dangerous goods?

Yes for many substances, but a rigid plastic IBC is not a blanket licence to store flammables. AS 1940 excludes the most volatile flammables — Class 3 packing group I — from rigid plastic intermediate bulk containers and tightly restricts low-flash-point liquids in them, because polymer containers soften and fail differently to steel in a fire. Plenty of combustible and less-volatile liquids, and a wide range of non-flammable chemicals, are perfectly suited to chemically compatible HDPE or PP containers with the right bunding.

For corrosives under AS 3780, the question flips from fire behaviour to chemical attack: here HDPE and PP are often the preferred material precisely because they resist acids and alkalis that corrode steel — provided the specific polymer suits the specific substance (verify against a chemical-compatibility chart and the container's UN marking). So the rule is two-sided. Plastic can be the wrong choice for a volatile flammable and the right choice for a corrosive. Match the polymer, the UN rating and the governing standard to the DG class before you commit — and for bulk liquids, choose a container built and certified for the job rather than retrofitting a general-purpose bin.

How does this play out on a mine site or packhouse?

On a mine site the three standards routinely fire at once, because reagent storage mixes flammable and corrosive dangerous goods on the same racked footprint. A gold operation holding flammable fuels and solvents (AS 1940) alongside corrosive acids for processing (AS 3780), racked on steel beams (AS 4084) and kept apart by segregation, is touching every layer in this guide. The right answer is heavy-duty, chemically compatible, hose-down equipment with a published racking rating — which is why mine sites lean on rugged HDPE pallets and bunded containment rather than timber and bare steel. See how that equipment set comes together across the mining range and in our mine-site spill containment guide, and browse compatible options in IBCs & bulk containers.

A produce packhouse usually lives in a gentler part of the map. Most of what it stores — vented bins of potatoes or onions, food-grade crates — is non-dangerous, so AS 1940 and AS 3780 rarely apply to the produce itself; the live standard there is AS 4084 the moment full bins go onto a rack, plus food-grade hygiene. But the cleaning store is the exception: sanitisers and some wash chemicals are corrosive or flammable, and the instant they are held in quantity, AS 3780 or AS 1940 applies to that cupboard even though the rest of the shed is food handling. The lesson is the same in both sectors — route every store by the class of its contents and the geometry of its racking. When you have a load to match, send the substance, quantity and freight postcode for a spec-backed quote, or compare equipment across the plastic pallet range and the recycling & resource-recovery hub.

Common questions

Is AS 1940 or AS 3780 the right standard for my chemical?

It depends on the dangerous-goods class. AS 1940 governs flammable and combustible liquids — broadly Class 3 and combustible C1/C2 liquids such as diesel, solvents and fuels. AS 3780 governs corrosive substances — Class 8 acids and alkalis such as sulphuric acid, hydrochloric acid and caustic soda. Read the Safety Data Sheet, find the DG class, and that tells you which standard to open first.

Does AS 4084 apply if I only store non-dangerous goods?

Yes. AS 4084:2023 governs the steel storage racking itself — its design, load limits, installation and inspection — and applies to any racked load, hazardous or not. The dangerous-goods standards (AS 1940, AS 3780) govern what is inside the package and how packages are segregated; AS 4084 governs the structure holding them up. The two layers are independent and usually both apply.

Can I store flammable liquids in a plastic IBC?

Only within strict limits. AS 1940 excludes the most volatile flammables (Class 3 packing group I, and tightly restricts low-flash liquids) from rigid plastic IBCs, because polymer containers behave differently to steel in a fire. Many combustible and less-volatile liquids are allowed in suitable HDPE/PP containers with the right bunding. Always confirm the specific liquid against AS 1940 and the container's UN marking before storing.

What happens when flammables and corrosives are stored together?

Both standards apply and a segregation requirement is added on top. Dangerous-goods classes that react together must be separated by distance or a barrier, so a store holding Class 3 flammables and Class 8 corrosives follows AS 1940 for the flammables, AS 3780 for the corrosives, and the segregation rules that keep them apart. None of the three standards replaces the others.

Do these standards tell me which pallet or bin to buy?

Indirectly. The DG standards set the containment, separation and compatibility rules your equipment has to meet; AS 4084 sets what the rack can carry. Together they define the spec — a chemically compatible, correctly bunded container with a published racking rating that covers your load at your beam span. The standards frame the requirement; the product has to satisfy all of it at once.

Sources: AS 1940 (The storage and handling of flammable and combustible liquids — including the Clause 5.9 secondary-containment rule and the restriction on flammable liquids in rigid plastic IBCs); AS 3780 (The storage and handling of corrosive substances — materials compatibility, containment and segregation); AS 4084:2023 (Steel storage racking — design, rating, installation and inspection), all Standards Australia. Regulatory framing from Safe Work Australia guidance on the storage of chemicals and on storage racking (safeworkaustralia.gov.au). Dangerous-goods classes per the Australian Dangerous Goods Code / GHS as shown on the product Safety Data Sheet. This guide is general information for Australian operators and routes a load to the right standard; it is not a substitute for the current published standards or advice from a licensed dangerous-goods consultant. Product capacity figures are manufacturer-tested ratings and vary with load distribution, beam span and temperature. Not a quote.