Installing new production equipment, relocating chemical storage or changing a factory layout can affect fire and explosion risks. During planning, engineering teams can still adjust equipment positions, ventilation and storage arrangements. Reviewing those risks at this stage can help identify problems before specifications are finalised and work begins on site.
Employers must review an existing DSEAR assessment when significant changes affect the workplace, work processes or organisation of work. They must also assess new work involving dangerous substances and put the necessary safety measures in place before it starts. An early review can identify potential releases, ignition sources and changes needed to existing controls.
If you are planning new machinery, process modifications or different storage arrangements, you need to understand how the proposals affect your current safety measures. This article explains when an existing assessment may need reviewing, how the findings can inform design choices and why hazardous area classification matters for equipment selection.
What Should You Know About DSEAR When Planning Site Changes?
- Significant changes to processes, equipment or storage may require the existing assessment to be reviewed and revised.
- Changes affecting potential explosive atmospheres can also affect hazardous area classification and equipment suitability.
- Reviewing risks during project planning can help teams incorporate suitable controls before new arrangements become operational.
Do Planned Site Changes Require a New DSEAR Assessment?
Not always. When significant changes affect the workplace, work processes or organisation of work, employers must review the existing assessment and revise it where necessary. The HSE Approved Code of Practice (L138) explains how plant and process modifications can affect previous findings.
A new activity involving dangerous substances must be assessed before it starts, with the necessary safety measures implemented. Not every modification requires a completely new assessment or revised hazardous area classification drawing. However, even minor changes should be checked for their potential effect on existing safety arrangements, with the assessment updated where necessary.
Which Site Changes Can Affect DSEAR Risks?
New equipment or changes to site operations can affect the release, accumulation or ignition of dangerous substances. Project teams should focus on modifications that could alter risks covered by the existing assessment.
Common examples include:
- New machinery: Installing or replacing equipment can introduce potential ignition sources or change how dangerous substances are handled, affecting equipment suitability.
- Changes to production processes: Modified operating conditions can affect the likelihood or extent of dangerous substance releases.
- Relocated chemical or fuel storage: Moving storage areas or changing stored quantities may affect containment, ventilation and proximity to ignition sources.
- Modified ventilation or extraction: Changes to airflow can influence how flammable gases, vapours or combustible dust disperse or accumulate.
- Revised workplace layouts: Altering the arrangement of equipment and work areas can affect ignition source management and existing hazardous area classifications.
At Safety First Group, our DSEAR risk assessment service can help you understand how proposed changes affect existing risks and where controls may need reviewing before installation.
How Can a DSEAR Assessment Inform Your Site Design?
An assessment can help project teams establish how a proposed change affects existing fire and explosion risks. The findings can identify potential releases of dangerous substances, possible ignition sources and controls that may need attention under the new arrangements.
Project teams can use this information to review equipment specifications, site layout, containment and ventilation. Any necessary changes can then be built into the design before equipment is purchased or installed.
Can Site Changes Affect Hazardous Area Classification?
Yes. Hazardous area classification identifies places where explosive atmospheres may occur, taking account of how frequently they could arise and how long they might persist. Where classification is necessary, it forms part of the wider risk assessment.
Changes to release points, enclosures or ventilation can affect the extent of a hazardous zone. A specialist review can establish if existing classifications remain suitable and inform the selection and positioning of electrical and non-electrical equipment. Not every modification requires a new zoning drawing; the findings should determine if an update is needed.
At What Stage of a Site Change Project Should DSEAR Be Reviewed?
The planning stage offers the greatest scope to act on assessment findings, while equipment locations, operating methods and design specifications can still be adjusted. Project teams can then consider necessary changes before procurement and installation decisions are finalised.
Before a new work activity involving dangerous substances begins, the necessary risk assessment and safety measures must be in place. This legal requirement is distinct from the practical benefit of involving a specialist earlier in the design process.
Installation and modification work can also create temporary risks. Hot work, maintenance or alterations to equipment that contains, or previously contained, dangerous substances may introduce fire or explosion hazards. These activities need suitable assessment and precautions before work begins.
What Should You Share with a DSEAR Specialist?
When contacting a specialist, it helps to have your current assessment and any hazardous area drawings available. Proposed site plans, equipment specifications, substance inventories and safety data sheets can also help establish what is changing. Details of planned operating conditions and ventilation arrangements can support an initial discussion about the review scope.
Do You Need to Review COSHH Alongside DSEAR?
Not automatically. Site changes affecting workers’ exposure to hazardous substances may also require a COSHH review. DSEAR addresses safety risks from dangerous substances, including fire, explosion and substances corrosive to metals. COSHH addresses risks to health from substances hazardous to health. For example, changes to flammable solvent handling can affect both ignition risks and employee exposure.
If the change affects exposure to hazardous substances, the existing COSHH risk assessment may also need reviewing. Looking at both sets of duties during planning helps project teams consider employee health alongside fire and explosion precautions.
Plan Site Changes with the Right DSEAR Information
Site changes involving dangerous substances should be checked against existing assessment findings before new arrangements become operational. Specialist advice during planning can help project teams make informed decisions about proposed equipment, working arrangements and safety controls.
At Safety First Group, we provide DSEAR risk assessments and hazardous area classification services for businesses planning site changes. If your project involves new equipment, process modifications or altered storage, contact our team to discuss your assessment requirements.