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Method Statement 2.24 - Working in Category "O" (Low Risk) Confined Space

Document Information

Field Value
Document Reference MS 2.24
Issue Number 2
Issue Date 1 June 2026
Next Review 1 June 2027
Prepared By Sean Ashton
Approved By Aaron Mason, Director
Task No Task PPE to be worn Plant required Reference is made to the Team Pack risk assessment
2.24 Working in Category "O" (Low Risk) Confined Space As defined by on-site risk assessment Calibrated 4-gas monitor, Communications equipment, Ventilation equipment, Emergency escape sets N/A

Hazards

  • Oxygen deficiency
  • Toxic gases (H₂S, CO)
  • Restricted escape
  • Flooding
  • Heat stress

Environmental Impacts

  • Ventilation exhaust
  • Emergency discharge

Customer Impacts

  • Service interruption
  • Access restrictions

Training Required

  • Confined space training (low risk)
  • Gas monitor use
  • Emergency procedures

Additional Plant and Equipment

  • Personal gas monitors
  • Safety harness if required
  • Adequate lighting
  • Rescue equipment on standby

Permits Required

Confined space entry permit required for all entries

COSHH Assessment Required

  • Assessment of potential atmospheric hazards
  • Cleaning chemical assessments

Sequence of Operations and Control Methods

Pre-Entry Procedures

  • Complete confined space permit
  • Identify all hazards
  • Isolate all services
  • Test atmosphere from outside
  • Leave monitor in space for minimum 5 minutes
  • Check readings:
    • Oxygen: 19.5% - 23.5%
    • LEL: 0%
    • H₂S: <5ppm
    • CO: <30ppm

Permit Requirements

  • Authorized person to complete permit
  • Define work scope clearly
  • List all precautions
  • Specify emergency arrangements
  • Set time limits
  • Display at entry point

Entry Procedures

  • Never work alone - minimum two persons
  • Continuous gas monitoring throughout
  • Maintain communication with surface
  • Secure safe access/egress route
  • Ventilation running continuously
  • Emergency plan understood by all

During Work

  • Monitor for condition changes
  • Watch for water ingress
  • Check gas monitor regularly
  • Evacuate immediately if alarm sounds
  • Take regular breaks outside
  • No petrol/diesel equipment inside
  • Only intrinsically safe electrical equipment

Emergency Procedures

  • Self-rescue is priority
  • Evacuate on any alarm
  • Raise alarm immediately
  • Never enter to rescue without proper equipment
  • Follow specific rescue plan
  • Call emergency services if required

Post-Work

  • Remove all equipment
  • Conduct final gas test
  • Sign off permit
  • Secure space against entry
  • Review any incidents
  • Confined Spaces Regulations 1997
  • HSE Guidance L101 - Safe work in confined spaces