A winter shutdown can bring welding, cutting and intensive cleaning into parts of a site where those activities seldom take place. Extraction systems are sometimes isolated for repairs while contractors work nearby. A COSHH assessment written for routine production will not always reflect these conditions.
Before work starts, compare the maintenance schedule with the existing assessment. This should reveal which precautions still apply and where information about employee exposure is missing.
If that review identifies an exposure question that existing evidence cannot answer, air sampling can help investigate it during the task. The assessment must establish suitable precautions first; monitoring provides supporting evidence and cannot take their place.
Why Can Winter Maintenance Change Workplace Exposure?
Maintenance work sometimes interrupts normal ventilation. Repairs can require extraction to be isolated, or dust-generating tasks to move beyond their usual capture points.
Closed doors and temporary enclosures also change airflow within a work area. Winter conditions alone do not establish a greater exposure risk. What matters is the activity taking place and the protection available to the people doing it.
Which Maintenance Tasks Can Release Dust, Fumes or Vapours?
The contaminants released depend on the material as well as the operation. Grinding metal produces particles from the metal and any coating, while welding generates fume and, depending on the process, gases. Cutting or drilling silica-containing concrete releases respirable dust that can contain crystalline silica.
Cleaning creates different exposures. Chemical products can release vapours or mists; work inside ducts or machinery can disturb accumulated dust. Before choosing a cleaning method, check the chemicals and deposits involved, rather than assuming the normal housekeeping arrangements will be suitable.
Check the available asbestos information before disturbing old insulation or coatings. If asbestos-containing materials are present or suspected, the work needs assessment under the relevant asbestos requirements. General workplace air sampling is not an alternative to identifying asbestos and applying the appropriate controls.
When Is Air Sampling Needed for Temporary Maintenance Work?
A maintenance task does not require monitoring simply because it generates dust or fume. The Control of Substances Hazardous to Health Regulations (COSHH) require employers to assess risks and prevent or adequately control exposure.
Monitoring becomes relevant when existing evidence is insufficient to establish adequate control or measurements are needed to assess exposure against a workplace exposure limit. The assessment must establish suitable precautions before work starts; sampling can then investigate a defined exposure question without delaying those precautions.
When the COSHH Assessment Does Not Cover the Planned Task
A COSHH assessment focused on routine production might not cover a one-off welding repair or intensive machinery clean. Check the planned substances, work methods and exposure conditions against its scope, then update any missing risks and controls before work begins.
Our COSHH risk assessment service can help businesses assess the work, review proposed controls and identify any gaps in exposure evidence.
When Ventilation or Extraction Arrangements Change
Isolating an extractor, opening an enclosure or moving welding away from its usual workstation changes how contaminants are captured. Suitable alternative controls need to be in place before work begins. If their effectiveness remains uncertain, exposure monitoring can provide further evidence.
Existing local exhaust ventilation (LEV) also needs to work properly. Our guide to how often local exhaust ventilation should be tested explains the separate examination and testing requirements for those systems.
When Several Contractors Work in the Same Area
Grinding beside welding or chemical cleaning can expose one team to substances generated by another. Assess the shared working area and airflow before deciding how to control that exposure. In some cases, separating activities or changing their timing will be more effective than relying on each team’s arrangements in isolation.
When Previous Monitoring No Longer Represents the Work
Results from routine production remain useful during a shutdown only when the materials, task duration and ventilation are comparable. Significant differences can justify further measurements.
Get the Right Exposure Evidence Before a Shutdown
When the assessment leaves a specific gap in exposure evidence, targeted monitoring helps investigate what workers inhale during the maintenance task.
Our occupational exposure monitoring service includes air sampling for dust, fumes and other airborne contaminants. We can plan measurements around the tasks and workers involved, so results reflect the conditions during maintenance.
How Should Workplace Air Sampling Be Planned?
Start with the exposure question the measurements need to answer. Welding repairs and machinery cleaning release different contaminants and take place over different periods, so the sampling plan needs to reflect the actual activity. This guides the choice of method, workers and timing.
What Is the Difference Between Personal and Static Air Sampling?
Personal sampling collects air near a worker’s breathing zone to estimate inhalation exposure. Static sampling operates at a fixed location, helping investigate airborne concentrations or contaminant movement in that area. Conditions at the fixed point can differ from those at the worker’s breathing zone, so the results are not interchangeable.
How Can Samples Represent Short Maintenance Tasks?
A welding sample collected mainly while tools are being prepared tells you little about exposure during active welding. The sampling period should capture the relevant work and take account of nearby activities. Short samples help characterise individual tasks, but they do not automatically represent exposure across a full shift.
Workplace exposure limits have specified reference periods, which must be considered when interpreting results. A measurement below a limit does not, on its own, demonstrate adequate control under COSHH.
What Should You Check Before a Winter Maintenance Shutdown?
Site managers should explain existing hazards and ventilation arrangements, while contractors confirm their equipment and work methods. Use these checks to identify gaps before work begins:
- Identify materials: Check metals, coatings, insulation, chemicals and accumulated deposits.
- Review tasks: Establish where cutting, welding, grinding or cleaning could release contaminants.
- Identify people at risk: Include contractors and others working nearby.
- Confirm controls: Check extraction, containment, segregation and respiratory protection where appropriate.
- Review the evidence: Decide if existing assessments are representative or further monitoring is needed.
What Can Air Sampling Results Tell Employers?
Interpret air sampling results alongside the activities and controls in place when the measurements were taken. Elevated dust exposure during machinery cleaning, for example, could lead to changes in extraction, cleaning methods or separation from nearby workers. The findings can also inform precautions for future shutdowns.
Are Your Maintenance Exposure Controls Ready for the Work?
Before maintenance begins, check that the existing assessments cover the substances, tasks and conditions involved. If an important exposure question remains unanswered, we can help identify the further assessment or monitoring that would be appropriate.
Contact our team to discuss the substances involved, your maintenance schedule and the controls already in place.