Confined Space Entry: Alternatives Technologies and Avoiding Entry

Confined Space Entry Part 2 by Robert Brown

confined space entry

Introduction

As you may recall, in Part 1 of this article we looked at the definition of a confined space and discussed why NOT to enter and the various hazards associated with confined space entries. Part 2 of the article will focus on alternative and creative approaches to avoid confined space entries.

What Are My Alternatives?

So, you ask, if I have tasks to perform, and yet, I have all of these risks and reasons not to enter, what are my alternatives? Let’s consider several specialized pieces of equipment as well as common, and not so common, techniques.

Product/Material Handling Equipment: High Power Vacuum Systems

In order to remove material from a confined space without entry, one option might be a high power vacuum system (Vactor or Guzzler). These systems can be truck or trailer mounted, can achieve air flows of 500 to 7000 cfm, and are capable of establishing 15 to 30 inches of Hg vacuum. The units can be equipped with suction lines of up to 8” in diameter, allowing for removal of even large debris, and will move material up to 1000 feet laterally. They can be operated in wet or dry mode, and may be further equipped with HEPA filtration. Other special options include explosion vents, special interior coatings, internal wash down systems, swing out cyclone collection, and specially designed drop-out collection containers. With a high power vacuum system you can move abrasives, brick, catalysts, cement, chemicals, oil, sludge/slurries, clay, coke, and virtually any other debris from virtually any confined space.

Specialized Cleaning Equipment

There are several options available for cleaning without entry. These may include water jet cleaning, abrasive blasting, and chemical cleaning.

Water jet Cleaning

The typical water jet system (also known as hydro-blasting equipment), depending upon the pump and configuration, can produce a water jet of 1000 to 100000 psi, at volumes of 1 to 100 gpm. This pressure can literally cut steel or concrete, and certainly, with the minimal volumes of water used, can be a creative cleaning solution. Water jet systems are in extensive use within a variety of industries, including pharmaceutical, chemical, petroleum, food processing, and transportation. In addition to “shotgun” cleaning wands, the units can be equipped with lances (for cleaning long portions of piping), and with cleaning heads that can operate at variable speeds, and can further clean three-dimensionally over 360 degrees of coverage. Specialized applications include telescoping booms, retractable units for cleaning railcars or horizontal tanks and skid mounted units for cleaning large diameter pipes. Water jet systems can even be included in a new engineering design to automate or semi-automate the cleaning process.

Abrasive Blasting

When someone mentions abrasive blasting, most people think of sandblasting. There are, however, several other options, the most intriguing being CO2 pellet blasting. The obvious advantage of CO2 as a cleaning media is that during the blasting process the “abrasive material” sublimes, leaving only the residue of the material previously in the space, now ready for easy removal.

Chemical Cleaning

There are a number of companies that specialize in chemical cleaning, using caustic or solvent cleaning materials to clean vessels, tanks, and other containers. Some of the cleaning materials are “off-the-shelf”, but experienced companies can develop customized cleaning solutions as well. Another chemical cleaning method is simple neutralization, which can be used quite effectively with acids and bases.

Repair Equipment

The increase in the use and availability of specialized robotics has created a wide variety of opportunities for avoiding entry into confined spaces. Mechanical cutting heads, remote welding capabilities, and guidelines combined with cameras allow for safer methods for repair and maintenance within confined spaces.

Inspection Equipment

While the use of IR and X-ray inspection or testing methods have been in use for many years, the increased sensitivity and improved methods are creating rapid advancements in the use of these techniques as opposed to direct visual inspection. An added bonus, of course, is that the results of these types of inspection actually yield more accurate results allowing for better decision making. Another inspection technique that continues to advance is the use of opto-electronic equipment use to inspect ducts, pipelines, drains and sewers from 6” to 80” in diameter. This equipment allows for inspection of live water and live gas lines, which eliminates the need for downtime; it is joystick controlled and resembles a technical version of a modern video game.

Non-Entry by Design

Regardless of whether some of the specialized equipment described above is used, or an alternative approach is taken, the best time to consider the prevention of the need to enter confined spaces is at the design stage. Consideration of approaches such as: removable agitators; fixed cleaning systems; oversized inspection plates/windows; and or clean-outs (such as bottom take offs) can simplify cleaning, repair and inspection, and eliminate or at least minimize the need for confined space entry.

Case Study

As an example of how creative approaches can improve task performance, consider the cleaning of a very large heavy oil storage tank. One approach, of course, is the “old method” of direct entry, which can be time consuming and more than a bit messy. One company specializing in this type of cleaning developed a very new approach, utilizing steam lancing with a “fluff and stir” technology. A complex manifold system allows for a faster, cleaner process which also results in a cleaner tank. How creative can you get when considering your options for dealing with confined spaces?

Safety Considerations

Every modified approach, of course, has the potential to create new hazards that did not previously exist. High pressure water blasting introduce the possibility of liquid injection injuries; high power vacuum systems introduce new sources of physical injury and noise; solvent cleaning processes may create flammable atmospheres, while other cleaning agents present new chemical hazards; and, CO2 blasting will likely result in oxygen deficient atmospheres. A process safety review should be performed whenever changes in approach occur.

Summary

Specialized equipment, changes to procedures, non-entry by design, and customized/creative approaches, can all eliminate or reduce the frequency of the need to enter confined spaces. Plan now for later and be creative. Just because it has always been done this way, does not mean it must be done this way in the future. Consider the new safety hazards that may be created, but always remember: the safest entry is no entry at all! Think about it.

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