OSHA CONFINED SPACE REG INTERPRETED FOR STORAGE TANK OPERATIONS

Philip E. Myers
Chevron Research & Technology Co.
Richmond, Calif.

A description of OSHA's recent confined space regulation explains its requirements and implications for aboveground storage tank operations.

A flow diagram has been designed to help determine which spaces qualify for regulation under the rule.

BACKGROUND

On Jan. 14, 1993, the U.S. Occupational Safety, & Health Administration (OSHA) adopted the final confined space entry rules, promulgated in 58 FR 4462. Compliance with these requirements began on Apr. 1%, 1993 (see 29 CFR 1910.146).

These regulations require employers to set up at all facilities a comprehensive program that includes, anion, other things:

Identification
Testing
Permitting
Training
Emergency response
Rescue.

Activities and areas associated with storage tanks that may be affected by this rule are:

Trenches for underground piping connections to tank
Tank inspection
Tank cleaning
Tank entrance, in the interior or at the top
Tank lining
Excavation in or around tanks
Secondary containment areas
Natural depression areas and other areas that could trap vapors or present other hazards.

Perhaps one of the most difficult problems is the determination of what constitutes a confined space. Is a secondary containment area, for example, or the roof of a tank a confined space? Designating such an area a confined space would alter current procedures and manpower associated with entering the area for inspection or other purposes.

For large companies with comprehensive safety and compliance staffs, only minor modifications to current company practices may be required. But for smaller companies without the benefit of these types of corporate staffs, major procedural changes may have to be adopted to achieve compliance with the intent of the regulation.

Another problem associated with confined space entry is visitors entering these areas. The regulation requires that persons must have had training before entering a confined space. Most companies will have to institute a brief training program so that personnel needing to enter a confined space may do so.

DETERMINATION

The regulation requires that employers evaluate the workplace to determine when confined space permits are required. The definition of a confined space is the simultaneous occurrence of three criteria:

The space is not designed for continuous employee occupancy
The human body can fit entirely within tile space 0 Access to the space is limited.

Once a space is determined to be confined, it must determine whether the confined space is permitted or nonpermitted. If any of the following criteria apply, it is a permitted space:

The space could contain hazardous atmosphere
The space could contain material that could engulf person
The space has a configuration that could trap or asphyxiate a person
The space contains any other recognized serious safety hazard.

A hazardous atmosphere is any condition that presents flammable, explosive, asphyxiating, or toxic vapors in a confined space. Entry is not allowed when the Oxygen concentration is less than 19.5% or greater than 23.5%, when the atmosphere is greater than 10% of the lower explosive limit, or when concentrations of toxic substances are greater than the permissible exposure limit.

Once confined spaces are identified, employers must alert employees to these locations by posting warning signs, or by other appropriate means. If employees will not be entering identified, permit required spaces in the course of their duties, the employer must take "effective measures" to prevent employees from doing so.

NONPERMITTED SPACES

The regulation may not require a permit when a space meets the following criteria: It is a mechanically ventilated, permitted space with only the first of the four hazards listed previously (the atmospheric hazard), and the permitted space has been reclassified as a nonpermitted space after the elimination of other hazards.

The employer is required to show that ventilation is adequate to prevent the accumulation of a hazardous atmosphere. This requires monitoring and inspection data to support this conclusion.

Before an employee can enter a ventilated confined space, the atmosphere must be tested for oxygen concentration, flammable gases and vapors, and other potential hazards. Before entry, the employer must certify in writing that the space is safe for entry.

ENTRY PROGRAM

Once confined spaces are identified, a written confined space entry program must be established. The program must include:

Prevention of unauthorized entry of permitted spaces
Procedures for safe entry, including identification of safe entry into confined spaces, ventilation requirements, and monitoring during entry
Provisions for use and maintenance of protective, testing, communications, and rescue equipment
Personnel with designated roles in confined space training and other responsibilities
An attendant outside the permitted space during entry operations
Procedures for summoning rescue and emergency services
Coordination of contractors involved in confined space entry
Provisions for concluding authorized entry
Review of confined space operations at least annually
Revisions to the program to correct deficiencies.

The most significant impact of this portion of the rule is the requirement that an attendant be posted outside the permitted confined space area.

PERMIT SYSTEM

The permit must identify:

The purpose of the entry
The identity, location, and hazards of the entry
The measures taken to control or eliminate the hazards
The date and duration of the permit
A system for tracking authorized entrants
The names of the current attendant and entry supervisor
Acceptable entry conditions
Recorded test results supporting entry conditions
Rescue and emergency services that can be summoned
Communication procedures to be used between attendant and entrants
A list of equipment used to comply with the requirements
Additional permits issued to authorize work in the permitted space.

TRAINING, DUTIES

The employer must provide appropriate training for all employees involved in confined space entry before assigning them to this work. Training must address the duties and responsibilities of each employee involved (typically authorized entrants, attendants, and entry supervisors).

The change that will cause the most impact on current practices is the requirement that all employees whose actions are regulated by the OSHA standard, including any, entrant, must have been trained.

Entrants must be aware of the exposure hazards, including symptoms and consequences. They must be in constant communication with the attendant so that the attendant can be alerted to any potential warning signs of exposure.

Permitted spaces must have posted at the edge of the confined area an attendant who is aware of all the potential hazards. He or she must maintain a record of all entrants and remain in communication the entire time the entrants are in the permitted area. Any condition, or potential condition, that poses a hazard requires the attendant to alert or evacuate the entrants.

The rule permits an attendant to enter the confined space only if the permit program allows: for example, during a rescue attempt for which the attendant has been equipped and trained and has backup relief.

Employers are required to ensure that adequate rescue and emergency services are available. If the employer performs these services, the personnel executing them must be properly trained and equipped. Training and practice sessions are required for these personnel at least annually.

The appendix to the new rule includes a flowchart to assist in understanding the rule. Fig, 1 is a version of that flow chart, modified to apply specifically to tanks.

STORAGE TANKS

Because the first step of the confined space rule requires the identification of confined spaces, several recommendations can be made to help remove some of the gray areas associated with storage tanks.

Each situation, however, is unique and every employer must be sure not to threaten the integrity of the confined space program by using "cook book" procedures, recommendations, or "armwaving" communication techniques.

RECOMMENDATIONS

Recommendations for storage tanks, as illustrated in Fig. 2, are:

The interior of all tanks should be considered a confined space. If, however, a large section of the tank shell called a "door sheet" cut out to enable personnel and equipment access to the tank interior could be considered a nonpermitted confined space, provided that the space is free of any of the hazards covered earlier.
The roof of external floating roof tanks should be considered a confined space unless it is within 5 ft of the top of the tank shell. Experience has shown that, although typical hydrocarbon gases emitting from external floating roof tank seals are heavier than air, they do not accumulate sufficiently to create a hazardous atmosphere when the roof is within 5 ft of the top of the shell. This, however, does not necessarily apply to extremely toxic chemical vapors.
The vapor space above the floating roof inside an internal floating roof tank should be considered a confined space.
The area surrounding a tank should be evaluated to determine whether it is a confined space when dikes or retaining walls enclose the tank, and when the height of secondary containment walls is greater than 5 ft.

CAVEAT

The new confined space rules do not assure that tank cleaning or tank entry will be safe. Cleaning a tank and removing it from service involves numerous hazards not covered in the OSHA rules.

Currently, the American Petroleum Institute is revising its API 2015 Standard "Safe Entry and Cleaning of Petroleum Storage Tanks," to provide the comprehensive guidance and considerations needed to ensure the health and well being of employees involved in this kind of work.

The OSHA program essentially formalizes and documents practices that many companies already follow. It also places liability for any incidents on the employer. The regulation is comprehensive enough that, had it been in force, it may have prevented some of the recent accidents relating to confined spaces in tanks.