Hazards and Solutions

Hazards encountered in petroleum and petrochemical storage tanks include, fire or explosion, asphyxiation, toxicity, entrapment, falls, and physical and chemical hazards including steam, heat, noise, cold and electrical shock. These hazards can be a result of the presence of hazardous gases, vapors, fumes, cleaning chemicals, dusts, improper or insufficient lockout-tagout, or excessive heat or cold. Additionally, the creation of an oxygen-deficient or oxygen-rich atmosphere may cause serious injury or death.

Most storage tanks have restricted means of entry and egress and are not intended for continuous human occupancy. Because they may contain hazards when taken out of service, most storage tanks will be considered Permit-Required Confined Spaces (PRCS). PRCSs are recognized by OSHA and the industry as presenting specific hazards that require special safety procedures in order to prevent accidents and injuries during entry. OSHA's permit-required confined spaces standard (29 CFR 1910.146) must be followed whenever employees enter permit spaces.

In addition, petroleum and petrochemical storage tanks present a unique classification of confined spaces. The American Petroleum Institute (API) and the National Fire Protection Association (NFPA) have developed a number of standards and codes that specifically address safe work practices while cleaning and entering petrochemical storage tanks. They are:

• ANSI/API Standard 2015, Requirements for Safe Entry and Cleaning of Petroleum Storage Tanks (August 2001).
• ANSI/API Recommended Practice 2016, Guidelines and Procedures for Entering and Cleaning Petroleum Storage Tanks, First Edition, (August 2001).
• NFPA 326 – Standard for the Safe Guarding of Tanks and Containers for Entry, Cleaning or Repair

More specific guidance is provided for the following Major Work Activities for Tank Cleaning Operations.

• Preplanning
• Training and Rescue
• Setting up equipment for tank entry and cleaning
• Removing Recoverable Product from Tanks using Fixed Connections and Piping (Decommissioning)
• Removing remaining product and tank bottoms through an entryway (without entry)
• Tank Isolation
• Vapor and Gas Freeing the Tank (Degassing)
• Atmospheric Testing the Tank Interior
• Cleaning the Tank
• Working Inside and Around the Tank
• De-isolation and Returning the Tank to Service
• Recommissioning