STANDARD OPERATING PROCEDURE

4Core Energy & Maintenance Ltd.

Standard Operating Procedures

CS-001: Confined Space Entry Permit

Effective Date: December 2025 Review Date: December 2026 Approved By: [Management Title] Revision: 1.0

Purpose

This procedure ensures safe entry into confined spaces by following WorkSafe BC requirements and preventing atmospheric hazards, engulfment, and other confined space dangers.

Scope

Use this procedure for ALL confined space entries at any work site. Includes tanks, vessels, boilers, pits, manholes, vaults, and any enclosed space meeting the confined space definition.

Definitions

Required Equipment and PPE

Equipment:

PPE:

Permits/Forms:

Roles and Responsibilities

Entry Supervisor:

Entrant:

Attendant:

Procedure

BEFORE YOU START

Hazards for this task:

[W020] Confined Space Hazards: - Restricted entry/exit, limited air circulation, not designed for continuous occupancy

[W016] Atmospheric Hazards: - Oxygen deficiency, toxic gases (H₂S, CO), flammable atmosphere (LEL)

[W021] Engulfment: - Liquids, solids, or free-flowing materials that can trap or bury workers

[W017] Physical Hazards: - Temperature extremes (hot surfaces or cold), noise, moving parts, sharp edges

[W012] Energy Hazards: - Unexpected release of electrical, mechanical, hydraulic, or process energy

Controls: - Complete isolation and lockout of all energy sources - Continuous atmospheric monitoring - Forced air ventilation - Rescue equipment ready and tested - Trained and equipped attendant - Emergency response plan in place

STEP-BY-STEP INSTRUCTIONS

  1. Review the work scope
    • What work needs to be done?
    • How long will it take?
    • How many workers need to enter?
    • What tools and materials are needed?
  2. Identify the space as confined space
    • Is it fully or partially enclosed?
    • Is it NOT designed for continuous human occupancy?
    • Does it have restricted entry or exit?
    • Is it large enough for a worker to bodily enter?
    • If YES to all four → It’s a confined space, use this procedure
  3. Complete hazard assessment
    • Review previous entry records for this space
    • Check equipment history and process information
    • Talk to client/owner about space contents and history
    • Identify ALL hazards (atmospheric, physical, process, configuration)
    • Determine what controls are needed
  4. Isolate all energy sources (See LO-001: Lockout/Tagout)
    • Electrical: Locked out at disconnect or panel
    • Mechanical: Equipment locked, de-energized, motion stopped
    • Process: Valves closed, locked, and tagged
    • Thermal: Cooled or heated to safe temperature
    • Hydraulic/Pneumatic: Depressurized, locked out
    • Gravity: Blocked or supported
    • Verify zero energy - attempt to start equipment, confirm it won’t move
  5. Isolate process connections
    • Close and lock all valves leading to space
    • Install physical blanks or blind flanges where possible
    • Verify isolation is complete
    • Tag all isolation points
  6. Purge and ventilate
    • Remove any residual atmosphere or contaminants
    • Flush space with fresh air (NOT oxygen, NOT inert gas)
    • [P001] Position blower intake in fresh air (not near exhaust, idling engines, or smoking areas)
    • Direct airflow to reach all areas of space
    • Continue ventilation throughout entry
    • Minimum 15 minutes ventilation before initial testing
  7. [M018] Test atmosphere (See GM-003: Confined Space Testing)
    • Bump test gas monitor BEFORE use (verify it responds to test gas)
    • Test at top, middle, and bottom of space (gases stratify)
    • Test in this specific order:
      1. Oxygen: Must be 19.5% to 23%
      2. Flammability (LEL): Must be less than 10%
      3. Carbon Monoxide: Must be less than 35 ppm
      4. Hydrogen Sulfide: Must be less than 10 ppm
    • Record all readings on permit
    • If ANY reading fails → DO NOT ENTER
    • Re-ventilate and re-test if readings are not acceptable
  8. Complete Confined Space Entry Permit
    • Fill out ALL sections (no blanks allowed)
    • Document hazards identified
    • List controls in place
    • Record atmospheric test results
    • Specify authorized entrants and attendant
    • Entry supervisor reviews and signs
    • Post permit at entry point where attendant can see it
    • Permit valid for ONE SHIFT ONLY (8-12 hours maximum)
  9. Position attendant
    • Attendant stationed at entry BEFORE anyone enters
    • Equipped with communication device (radio or phone)
    • Has copy of permit and emergency contacts
    • Equipped with continuous gas monitor if IDLH atmosphere possible
    • Attendant NEVER leaves position while someone is inside
    • Attendant maintains count of entrants
  10. Set up rescue equipment
    • For vertical entries: Tripod/davit positioned and secured
    • Retrieval line attached to entrant’s harness D-ring
    • Winch or retrieval device tested (lift test with weight)
    • Fire department or rescue team notified if required by permit
    • Emergency contact numbers confirmed and readily available
    • All rescue equipment inspected and ready to use
  11. Final verification before entry
    • Permit complete and posted? ✓
    • Atmosphere acceptable? ✓
    • Ventilation running? ✓
    • Lockout verified? ✓
    • Attendant in position? ✓
    • Communication established? ✓
    • Rescue equipment ready? ✓
    • ALL YES? → Entry authorized
  12. Enter the space
    • Entrant dons required PPE and harness
    • Attach retrieval line to harness D-ring
    • Test atmosphere immediately at entry point
    • Establish communication with attendant
    • Enter slowly, monitoring for symptoms (dizziness, nausea, difficulty breathing)
    • If you feel unwell AT ALL → Exit immediately
  13. During work inside space
    • Maintain continuous or periodic communication with attendant
    • Continuous atmospheric monitoring (personal monitor on entrant)
    • Record readings every 15 minutes minimum
    • Keep ventilation running at all times
    • Exit immediately if:
      • Atmosphere readings change
      • You feel dizzy, nauseous, or “off”
      • Ventilation fails or stops
      • You hear/smell anything unusual
      • Attendant orders evacuation
      • Any alarm sounds
  14. Monitor conditions outside space
    • Attendant watches for changing weather (rain could flood space)
    • Watch for activities that could affect space (nearby welding, chemical use)
    • Monitor ventilation blower operation
    • Keep unauthorized people away from entry
    • Maintain accurate count of entrants
  15. Exit and close-out
    • Remove all tools, equipment, and materials from space
    • Verify space is clean (no debris, rags, or foreign objects)
    • All entrants sign out on permit
    • Entry supervisor signs permit close-out
    • Restore equipment to service if applicable (remove lockouts per LO-001)
    • Review any issues, near-misses, or lessons learned
    • File completed permit (retain for minimum 2 years)

Warning STOP WORK CONDITIONS

Stop work immediately and exit the space if: - Atmospheric readings change (any parameter out of range) - Gas monitor alarms activate - You feel dizzy, nauseous, lightheaded, or “off” - You have difficulty breathing - Ventilation system fails or stops - You hear or smell anything unusual - You see unexpected liquid, vapor, or material - Attendant orders evacuation - Emergency alarm sounds - Weather conditions change (lightning, heavy rain) - Unauthorized work starts nearby

DO NOT re-enter until Entry Supervisor investigates, resolves the issue, and approves re-entry.

[E003] Emergency Response

If someone is in distress inside the confined space:

  1. [P003] DO NOT ENTER TO RESCUE
    • Most confined space fatalities are would-be rescuers
    • Untrained rescue attempts kill more people than the original incident
    • Dead heroes don’t save anyone
  2. [E009] Attendant: Activate emergency response immediately
    • Call 911 or site emergency number
    • Provide location and nature of emergency
    • State “Confined space rescue needed”
    • Give space description and number of victims
  3. Attempt non-entry rescue if possible
    • If retrieval line is attached: Use winch to pull entrant out
    • Do this only if you can do it from outside the space
    • Do not enter the space yourself
  4. If non-entry rescue not possible: Wait for trained rescue team
    • Do not attempt entry
    • Keep everyone away from the opening
    • Be ready to provide information to rescue team
  5. Attendant: Account for all personnel
    • Confirm who is inside, who is out
    • Provide names to emergency responders
    • Prevent anyone else from entering
  6. Entry Supervisor: Manage the scene
    • Take control of the emergency
    • Keep area clear for rescue team
    • Provide permit and hazard information to responders
    • Notify management immediately
    • Preserve scene for investigation (after rescue complete)

Remember: The best rescue is the one that never needs to happen. Follow procedures.

Ventilation Requirements and Calculations

All confined space entries require continuous forced-air ventilation. The volume of air required depends on the size of the space and the work being performed.

Calculating Required Air Flow

Basic Formula:

Required Air Flow (CFM) = (Space Volume in ft³ × Air Changes per Hour) ÷ 60 minutes

Where: - CFM = Cubic Feet per Minute - Space Volume = Length × Width × Height (or calculated volume for cylindrical vessels) - Air Changes per Hour = Number of times entire air volume is replaced each hour

Air Change Rates by Activity Level

Activity Type Air Changes/Hour When to Use
Inspection Only (No Work) 6 ACH Visual inspection, no tools, no dust generation
Light Work 10 ACH Hand tools, minimal dust, no cutting/grinding
Medium Hazard Work 20 ACH Grinding, cutting, welding fume generation, dusty work
Heavy Contamination 30+ ACH Hot work, heavy grinding, chemical cleaning

Example Calculations

Example 1: Inspection Only - Small Thermal Oil Heater

Space: Combustion chamber 4 ft wide × 4 ft deep × 3 ft high = 48 ft³

Activity: Visual inspection, no work performed

Calculation:

Required CFM = (48 ft³ × 6 ACH) ÷ 60 min
Required CFM = 288 ÷ 60
Required CFM = 4.8 CFM (round up to 5 CFM minimum)

Blower Selection: Use minimum 200 CFM blower (standard confined space blower provides excess ventilation for safety margin)

Example 2: Medium Hazard Work - Boiler Tube Cleaning with Grinding

Space: Firetube boiler 6 ft diameter × 12 ft long

Volume Calculation (cylindrical):

Volume = π × r² × L
Volume = 3.14 × (3 ft)² × 12 ft
Volume = 3.14 × 9 × 12
Volume = 339 ft³

Activity: Grinding refractory, generates dust (Medium Hazard)

Calculation:

Required CFM = (339 ft³ × 20 ACH) ÷ 60 min
Required CFM = 6,780 ÷ 60
Required CFM = 113 CFM

Blower Selection: Use 200+ CFM blower, positioned to create cross-ventilation (intake at one end, natural exhaust at other)

Additional Controls for Medium Hazard: - Personal continuous atmospheric monitoring on entrant - Respiratory protection if dust exceeds exposure limits - More frequent atmospheric testing (every 10-15 minutes) - Enhanced communication (maintain constant contact)

Practical Blower Sizing

4Core Standard Equipment: - Small confined space blower: 200-300 CFM (suitable for most inspection work and small spaces) - Large confined space blower: 500-1000 CFM (for larger vessels or medium/heavy hazard work)

Selection Guidelines: - Always oversize - more ventilation is safer - Minimum 200 CFM for ANY confined space entry - Double the calculated CFM for spaces with complex geometry (baffles, tubes, dead zones) - If space has internal obstructions, use high-velocity blower and ducting to reach all areas

Ventilation Positioning: - Position blower intake in clean, fresh air (not near exhaust, engines, or contaminants) - Direct airflow to sweep across entire space - For vertical entries: blow air DOWN to bottom, exhaust naturally rises - For horizontal entries: blow air to far end, exhaust at entry point - Never recirculate air from inside the space

Continuous Operation Required: - Ventilation MUST run continuously during entire entry - Do not turn off blower “to hear better” or “to reduce noise” - If blower fails: evacuate immediately, investigate, restart ventilation, re-test atmosphere before re-entry

Revision History

Version Date Changes Approved By
1.0 December 2025 Initial release [Management Title]

QUESTIONS? ASK YOUR SUPERVISOR BEFORE STARTING WORK.

4Core SOPs | Updated: December 2025

CONTROLLED DOCUMENT: Always verify you have the current version.

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