Safe Work Procedure: Confined Space Entry into Acid Tank

Document Number: [SWP-NUMBER] Revision Date: [DATE] Next Review Date: [NEXT REVIEW DATE] Department: [DEPARTMENT NAME]

1. Scope

This Safe Work Procedure (SWP) outlines the necessary safety precautions and procedures to be followed when entering acid tanks that are considered confined spaces. It applies to all personnel who are required to enter, work in, or supervise work activities within acid tanks. This procedure aims to minimize the risks associated with confined space entry, including exposure to hazardous atmospheres, engulfment, and other potential hazards [1]. This SWP is to be used in conjunction with the site's Confined Space Entry Program and all other relevant safety procedures.

2. Definitions

Confined Space: An enclosed or partially enclosed space that is not primarily designed or intended for human occupancy, has restricted means of entrance and exit, and may contain or produce hazardous conditions or atmospheres [2].

Hazardous Atmosphere: An atmosphere that may expose employees to the risk of death, incapacitation, impairment of ability to self-rescue, injury, or acute illness due to the presence of flammable, explosive, toxic, corrosive, asphyxiating, or otherwise harmful air contaminants, or an oxygen level outside the safe range of 19.5% to 23.0% 2, 13.

Entry Permit: A written document that authorizes entry into a confined space, verifies that pre-entry requirements have been met, and specifies the conditions under which entry is allowed [3].

Attendant/Tending Worker: A competent person stationed outside the confined space who monitors the authorized entrants, ensures their safety, and summons rescue services if needed [4].

IDLH (Immediately Dangerous to Life or Health): Any condition that poses an immediate or delayed threat to life or that would cause irreversible adverse health effects or interfere with an individual's ability to escape unaided from a permit space [5].

3. Responsibilities

3.1 Supervisors

• Ensure that a Confined Space Entry Permit is completed and signed before any entry is allowed [3].
• Ensure that all workers involved are adequately trained and competent to perform their assigned tasks [6].
• Provide workers with the necessary personal protective equipment (PPE) and ensure its proper use [3].
• Ensure that the atmosphere within the confined space is tested and monitored before and during entry [7].
• Ensure that adequate ventilation is provided to maintain a safe atmosphere [6].
• Ensure that emergency procedures and rescue plans are in place and readily available [8].

3.2 Workers

• Participate in required training and understand the hazards associated with confined space entry [6].
• Follow all safety procedures and instructions outlined in the Confined Space Entry Permit and this SWP [3].
• Use the provided PPE properly and report any defects or damage [3].
• Monitor the atmosphere and immediately evacuate the confined space if any hazardous conditions are detected [8].
• Maintain communication with the attendant and report any concerns or emergencies [4].

3.3 Health and Safety Representative

• Assist in the development and review of confined space entry procedures and programs [6].
• Conduct regular audits of confined space entry activities to ensure compliance with safety regulations 17, 6.
• Investigate incidents and near-misses related to confined space entry and recommend corrective actions [9].

4. Potential Hazards and Risks

Hazard	Risk	Control Measures
Oxygen deficiency or enrichment	Asphyxiation, fire, or explosion	Test atmosphere before entry; provide continuous ventilation; use air-supplied respirators 2, 13, 19
Toxic gases or vapors (e.g., acid fumes)	Acute or chronic health effects, irritation, corrosion	Test atmosphere before entry; provide continuous ventilation; use appropriate respirators and PPE 17, 19
Flammable or explosive substances	Fire or explosion	Test atmosphere before entry; eliminate ignition sources; use intrinsically safe equipment [10]
Chemical exposure (acids)	Skin burns, eye damage, respiratory irritation	Use appropriate PPE (gloves, eye protection, aprons); provide deluge shower and eyewash station [1]
Engulfment (liquids or free-flowing solids)	Drowning or suffocation	Remove liquids or solids before entry; implement lockout/tagout procedures to prevent entry of materials [11]
Physical hazards (e.g., moving parts, sharp edges)	Cuts, lacerations, crushing injuries	Lockout/tagout equipment; use appropriate tools and equipment; ensure proper lighting [11]
Poor communication	Delayed response in emergencies	Establish and maintain two-way communication between entrant and attendant [4]

5. Personal Protective Equipment (PPE)

Proper PPE is essential for protecting workers from the hazards associated with confined space entry. All PPE must be inspected before use to ensure it is in good working condition [3].

• Respirator: Use a supplied-air respirator (SAR) or self-contained breathing apparatus (SCBA) when the atmosphere is IDLH or cannot be adequately ventilated 5, 11. Ensure proper fit testing and training.
• Eye Protection: Wear chemical splash goggles or a full-face shield to protect against acid splashes or fumes [1].
• Gloves: Use chemical-resistant gloves (e.g., nitrile, neoprene) to prevent skin contact with acids [1].
• Protective Clothing: Wear a chemical-resistant suit or apron to protect the body from acid splashes or spills [1].
• Boots: Use rubber or chemical-resistant boots to protect feet from acid exposure [1].
• Hard Hat: Wear a hard hat to protect against head injuries from falling objects or low clearances [12].
• Harness and Lifeline: Use a full-body harness with a lifeline for retrieval in case of emergency, if feasible and does not create additional hazards 4, 11.

Inspect PPE for damage before each use. Clean and store PPE according to manufacturer's instructions.

6. Equipment and Tools

Ensure all equipment and tools are in good working condition and appropriate for the task. Inspect equipment before each use.

• Atmospheric Monitoring Equipment: Use calibrated multi-gas meters to test for oxygen levels, flammable gases, and toxic substances (e.g., hydrogen sulfide, carbon monoxide) 9, 13.
• Ventilation Equipment: Use portable fans or blowers to ventilate the confined space and maintain a safe atmosphere 3, 7.
• Communication Equipment: Use two-way radios or other communication devices to maintain constant contact between the entrant and attendant [4].
• Lighting: Use explosion-proof lighting to provide adequate illumination within the confined space [10].
• Retrieval System: Use a tripod and winch system or other mechanical retrieval device to facilitate non-entry rescue 5, 10.
• Lockout/Tagout Equipment: Use locks, tags, and other devices to isolate energy sources and prevent accidental activation of equipment [12].

7. Pre-Job Requirements

7.1 Training and Competency

• All personnel involved in confined space entry must be trained in accordance with regulatory requirements and the site's Confined Space Entry Program [6].
• Training must include hazard recognition, atmospheric monitoring, PPE use, entry procedures, rescue procedures, and the duties of entrants and attendants [13].
• Workers must demonstrate competency in performing their assigned tasks before being allowed to participate in confined space entry activities [6].

7.2 Pre-Job Briefing

• Conduct a pre-job briefing with all personnel involved to discuss the scope of work, potential hazards, control measures, and emergency procedures [3].
• Review the Confined Space Entry Permit and ensure that all requirements are understood and followed [3].
• Confirm that all necessary equipment and PPE are available and in good working condition [3].
• Establish clear communication signals and procedures between the entrant and attendant [4].

7.3 Work Area Preparation

• Isolate the acid tank by disconnecting or blanking off all pipelines and energy sources [11].
• Implement lockout/tagout procedures to prevent accidental activation of equipment or entry of materials [12].
• Ensure that the confined space is thoroughly cleaned and purged of any residual chemicals or materials [14].
• Provide adequate ventilation to remove hazardous atmospheres and maintain a safe oxygen level 3, 7.
• Set up a retrieval system and ensure that it is properly anchored and rigged 5, 10.
• Establish a clear and unobstructed entry and exit path [15].
• Barricade or cordon off the work area to prevent unauthorized entry [7].

8. Safe Work Procedure Steps

Step 1: Atmospheric Testing and Monitoring

Before entry, a competent person must test the atmosphere inside the acid tank using calibrated instruments 9, 13.

• Test for oxygen levels, flammable gases, and toxic substances 9, 13.
• Ensure that the oxygen level is between 19.5% and 23.0% by volume 2, 13.
• Ensure that the concentration of flammable gases is below 10% of the lower explosive limit (LEL) [10].
• Ensure that the concentration of toxic substances is below the permissible exposure limit (PEL) 2, 13.
• Continuously monitor the atmosphere during entry, especially if conditions may change unpredictably 13, 19.

Safety considerations: If the atmosphere is not safe, do not enter the confined space. Implement additional ventilation or other control measures until a safe atmosphere is achieved 7, 19.

Step 2: Entry and Work

Once a safe atmosphere is confirmed, workers may enter the acid tank to perform the necessary tasks [3].

• Ensure that the entrant is wearing the required PPE, including a respirator, eye protection, gloves, and protective clothing 4, 11.
• Use a full-body harness with a lifeline if feasible and does not create additional hazards 4, 11.
• Maintain constant communication with the attendant outside the confined space [4].
• Perform work in a safe and controlled manner, following established procedures [6].
• Avoid creating ignition sources if flammable substances may be present [10].

Safety considerations: If any hazardous conditions are detected during entry, immediately evacuate the confined space and reassess the situation [8].

Step 3: Exit and Closure

After completing the work, workers must exit the acid tank safely and the confined space must be properly closed [3].

• Ensure that all personnel and equipment are removed from the confined space [6].
• Remove any lockout/tagout devices and restore equipment to its normal operating condition, if applicable [12].
• Close and secure the confined space to prevent unauthorized entry [7].
• Document the completion of the work and any relevant observations on the Confined Space Entry Permit [3].

Safety considerations: Ensure that the confined space is left in a safe condition before closing it [16].

9. Precautions and Safety Measures

• Entry Permit: Always obtain a signed entry permit before entering the confined space [3].
• Atmospheric Monitoring: Continuously monitor the atmosphere for hazardous conditions 13, 19.
• Ventilation: Ensure adequate ventilation to maintain a safe atmosphere 3, 7.
• PPE: Use appropriate personal protective equipment, including respiratory protection 4, 11.
• Communication: Maintain constant communication between the entrant and attendant [4].
• Emergency Procedures: Be familiar with emergency procedures and rescue plans [8].
• Lockout/Tagout: Follow lockout/tagout procedures to isolate energy sources [12].
• No Unauthorized Entry: Prevent unauthorized entry into the confined space [7].
• Fall Protection: Use fall protection equipment when working at heights 4, 11.
• Hot Work: Avoid hot work (welding, cutting, etc.) unless the confined space is free of flammable materials and vapors [14].

10. Emergency Procedures

10.1 General Emergency Response

• In the event of an emergency, immediately activate the site's emergency response plan [8].
• Evacuate the confined space and the surrounding area [8].
• Contact emergency services (e.g., fire department, medical personnel) [13].
• Provide first aid and medical assistance to injured personnel [6].
• Secure the area and prevent further entry [7].

10.2 Specific Emergency Scenarios

• Atmospheric Hazard: If a hazardous atmosphere is detected, evacuate immediately and ventilate the space 7, 19.
• Entrapment: If a worker becomes entrapped, use the retrieval system to remove them from the confined space 5, 10.
• Chemical Exposure: If a worker is exposed to chemicals, flush the affected area with water and seek medical attention [1].
• Injury: If a worker is injured, provide first aid and arrange for medical transport [6].

10.3 Emergency Contact Information

• Emergency Services: 911
• Site Security: [PHONE NUMBER]
• First Aid: [PHONE NUMBER]
• Supervisor: [PHONE NUMBER]
• Health and Safety: [PHONE NUMBER]

11. Incident Reporting and Investigation

• All incidents, near-misses, and hazards related to confined space entry must be reported to the supervisor and health and safety department [9].
• An investigation will be conducted to determine the root cause of the incident and implement corrective actions to prevent recurrence [9].

12. References and Related Documents

• Occupational Health and Safety Regulations 2, 3, 4, 7, 8, 10, 11, 12, 13, 14, 15, 18, 19, 20
• Site-Specific Confined Space Entry Program
• Confined Space Entry Permit
• Lockout/Tagout Procedure
• Emergency Response Plan
• SDS (Safety Data Sheets) for Acids and Other Chemicals

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Approved by: [NAME AND POSITION] Date: [APPROVAL DATE]

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