How to identify and manage explosive substances – Part 1

How to identify and manage explosive substances – Part 1

Tristan Pulford, Principal Consultant at Finch Consulting, delves into the core elements of how to identify and manage potentially explosive substances, emphasising how employers can recognise and mitigate hazards associated with explosive substances and atmospheres, with a primary focus on safeguarding the health and safety of workers.



Written by

Tristan Pulford

Many industries around the world operate using potentially explosive substances ranging from the ingredients that go into foods, to plastics that are handled as part of manufacturing products. In some cases, the bulk material handled may not be potentially explosive, but through handling it or manipulating it the properties such as particle size, moisture content, or composition change so that it becomes potentially explosive.

In the UK the regulations enforcing safety for explosive substances is called the Dangerous Substances and Explosive Atmosphere Regulations (DSEAR) which were published in 2002. These regulations attempt to control the creation of any potential explosive atmospheres (where there is fuel, oxygen, and an ignition source) to as low as reasonably practicable, through various organisational methods.

Potentially Explosive Substances and DSEAR

Some of the substances used, whether they be dusts, liquids, vapours, or gases may fall under the Dangerous Substances and Explosive Atmosphere Regulations. Obviously to comply with these regulations the first step is to identify that the substances being handled are potentially explosive.

So how can you tell whether a substance is potentially explosive? The HSE define a dangerous substance (with regards to DSEAR) as:

“Dangerous substances are any substances used or present at work that could, if not properly controlled, cause harm to people as a result of a fire or explosion or corrosion of metal.”

If a MSDS is created properly then Section 2 (Hazards Identification) should be the only section that is required to identify whether the substance may fall under DSEAR. Any substance which is listed as flammable, very flammable, oxidising or corrosive falls under DSEAR, if it is a dust or fluid. In my experience however section 2 can be badly filled in or may include a note at the bottom stating “May be explosive when in powder form” or equivalent.

The properties of the substance can also be confirmed within section 9 of the MSDS (Physical and Chemical Properties) which includes details including the potentially explosive properties. It should be noted that any liquid with a flash point above 60 °C does not fall under DSEAR unless it is handled above this temperature.

Understanding the process

One of the largest risks for any site which handles potentially explosive substances, particularly when mixing or process these substances, is understanding of the process. There are many examples of explosions occurring across various industries where misunderstanding reactions, pressures or release points has led to severe explosions.

Dependant on the industry, good practice to understand the process is to analyse the Piping & Instrumentation Diagrams (P&IDs) and carrying out a Hazard and Operability (HAZOP) study. With an independent competent chair and the appropriate team, this process will identify any areas where a process deviation may lead to a reaction or leak which affects the hazardous area classification or ignition assessment associated with DSEAR.

If there is any uncertainty in the assessment process it is recommended that you approach an independent consultancy to assist in carrying this out, as any uncertainty can cause potential hazardous scenarios, hazardous consequences, and protective systems to be missed, leading to unidentified explosion risks.

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