Plain English guide

What is a DSEAR risk assessment?

It is a written assessment of the fire and explosion risk created by the dangerous substances on your site, and of what you are doing about it.

The short version

The Dangerous Substances and Explosive Atmospheres Regulations 2002 require every employer to assess the risk from dangerous substances before work starts, and to keep that assessment current. A dangerous substance is anything that can catch fire or explode at work, plus, since a 2015 amendment, gases under pressure and substances corrosive to metals.

The point most people miss: DSEAR is not about how much you hold. It is about whether an explosive atmosphere can form. A shallow tray of solvent in a poorly ventilated room can put you in scope faster than a properly bunded bulk tank outside.

What the regulations actually ask for

RegulationWhat it requires
Reg 5Carry out a risk assessment covering the substances, the likelihood of an explosive atmosphere, ignition sources and the consequences.
Reg 6Eliminate the risk where you can. Where you cannot, control it and mitigate the effects.
Reg 7Classify places where explosive atmospheres may occur into zones, and make sure equipment in those zones is suitable.
Reg 8Put emergency arrangements in place: procedures, drills, escape, first aid, warning systems.
Reg 9Give employees information, instruction and training on the substances and the controls.
Reg 10Mark containers and pipework carrying dangerous substances.

An assessment that only covers Regulation 5 and stops is the most common failing we see. Zoning and emergency arrangements are where inspections tend to land.

The zones, and what they mean for your equipment

Once you know where an explosive atmosphere can form, you classify those places. Zoning is what tells your electrician which equipment is legal to install.

ZoneGas, vapour or mistEquipment category
Zone 0Present continuously, for long periods, or frequentlyCategory 1
Zone 1Likely to occur occasionally in normal operationCategory 2
Zone 2Not likely in normal operation, and only briefly if it doesCategory 3
ZoneCombustible dustEquipment category
Zone 20Dust cloud present continuously, for long periods, or frequentlyCategory 1
Zone 21Likely to occur occasionally in normal operationCategory 2
Zone 22Not likely in normal operation, and only briefly if it doesCategory 3

More on hazardous area classification and zoning drawings →

Ignition sources people forget

Questions we get asked

What does DSEAR stand for?

The Dangerous Substances and Explosive Atmospheres Regulations 2002.

Who enforces DSEAR?

The HSE on most industrial sites, and the local authority in some retail and warehousing settings. Fire and rescue authorities also take an interest where DSEAR overlaps with the Regulatory Reform (Fire Safety) Order 2005.

Does DSEAR apply to small businesses?

Yes. The regulations do not set a threshold quantity. A small joinery shop with a dust extractor, or a garage with a parts washer, is in scope in exactly the same way a refinery is. What changes is the depth of assessment that is reasonable.

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