The liquid is rarely the problem. The vapour above it is, and vapour goes where the ventilation sends it.
A liquid gives off vapour continuously. Whether that vapour can form an explosive atmosphere at the temperature your workshop actually runs at is what the flash point tells you. Something with a flash point below ambient is producing an ignitable mixture in the headspace of the drum all day, every day, without anybody doing anything.
That is why the safety data sheet is the first thing we ask for, and why an assessment based on what the labels say rather than on what the sheets say is not worth much.
Whether drums, IBCs and jerry cans are closed when not in use, and whether the ones in daily use ever actually get closed.
The single highest-risk operation on most sites. Bonding and earthing, plastic containers, funnels, and where the displaced vapour goes.
Natural or mechanical, high and low level, and whether it still works now the racking has been moved in front of it.
Bunding, drainage, and what would happen to a full IBC failing at four in the afternoon.
Electrical fittings inside the store, forklifts driving through, hot work, static, and mobile phones carried in by contractors.
Distance from boundaries, occupied buildings and other stored substances, especially oxidisers.
There is no threshold. DSEAR applies as soon as a dangerous substance is present at work. Separate storage quantity limits do exist in guidance for what may be kept in a workroom, but they are about good practice, not about whether you need an assessment.
If a spill could reach a drain, a watercourse or an ignition source, almost certainly. The usual benchmark is retention of 110 percent of the largest container, and on the Milford Haven Waterway the environmental consequences of getting it wrong are taken seriously.
A cabinet controls a small quantity in a workroom. It does not remove the need for an assessment, and it does nothing about the vapour released when someone decants at the bench next to it.
It depends on the release sources and the ventilation. A well-ventilated external store with closed containers often ends up with a small Zone 2 around vents and fill points. An unventilated internal decanting room can be considerably worse.
How the zones around a store and its vents are worked out.
What can legally be installed once a zone exists.
Fixed price, quoted after a short scoping call.
No charge for the conversation. Most quotes go out the same day.